CA1169816A - Process using detectable marking compounds to sort particles - Google Patents
Process using detectable marking compounds to sort particlesInfo
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- CA1169816A CA1169816A CA000365877A CA365877A CA1169816A CA 1169816 A CA1169816 A CA 1169816A CA 000365877 A CA000365877 A CA 000365877A CA 365877 A CA365877 A CA 365877A CA 1169816 A CA1169816 A CA 1169816A
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Abstract
Reg. No. 013/729-80 ABSTRACT OF THE DISCLOSURE
A process for separating one type of particle (e.g., ore particles) from a second type of particle (e.g., gangue particles) comprises the steps of (1) conditioning the particles with an agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively coat one type of particle (i.e.
either the ore particles or the gangue particles), to the substantial exclusion of the other; (2) detecting the coated particles; and (3) separating the detected coated particles from the substantially uncoated particles. In one embodiment, the detectable moiety is fluorescent and detecting is performed under ultraviolet radiation. The process is especially useful for separating higher grade limestone from lower grade limestone and/or gangue or for separating oil shale or coal of high BTU value from lower BTU materials or for concentrating valuable minerals, such as silver or copper ores.
A process for separating one type of particle (e.g., ore particles) from a second type of particle (e.g., gangue particles) comprises the steps of (1) conditioning the particles with an agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively coat one type of particle (i.e.
either the ore particles or the gangue particles), to the substantial exclusion of the other; (2) detecting the coated particles; and (3) separating the detected coated particles from the substantially uncoated particles. In one embodiment, the detectable moiety is fluorescent and detecting is performed under ultraviolet radiation. The process is especially useful for separating higher grade limestone from lower grade limestone and/or gangue or for separating oil shale or coal of high BTU value from lower BTU materials or for concentrating valuable minerals, such as silver or copper ores.
Description
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This invention relates to compounds which contain both a surface-selective functional group and a detectable moiety, such as one which will fluoresce under ultraviolet light, and the use of such compounds in selectively marking, as by coating, certain components of a mixture of ore particles to the substantial exclusion of other particles. The detectable portion can have a visible color, can fluoresce, can emit radiation, or can be induced (as by further chemical reaction or exposure -to electro-magnetic radiation or sub-atomic particles~ to exhibit a charac-teristic property. The invention is particularly well suited foruse with a mechanical apparatus for sorting ore particles, such as an electro-optical separator.
A known method describes concentrating ore which involves preferentially coating the desired particles with a li~uid fluore-scent material, subjecting the ore to electromagnetic radiation so that at least the coated portion will fluoresce, and sensing the - ~l16~
characteristic fluorescent wavelength emitted by the irradiated particles.
An apparatus is known which senses the emitted fluorescent radiation from gangue or ore particles, especially coated particles, and separates by selectively directing streams of a fluid to cause those fluorescent particles to be removed from the remaining quantity of undesired ore.
A further process and apparatus are known which are similar to those previously described. Successful operation of a mechanical sorting device in such known apparatus is dependent upon the ability to selectively coat ~or otherwise mark) either gangue or ore particles which contain a particular mineral component, while not coating (or marking) the other particles to a significant extent. The surface chemical properties of a specific ore or gangue particle depend upon the minerals which are present in that particle and, since the composition of individual particles can show a wide variation, the surface chemical properties of the particles will also vary.
To utilize a difference in surface chemical properties in the separation of ore particles, it is necessar~ to contact the mixture of particles with a surface-selective agent which will selectively react with certain mineral species present in the particles, due to the selectivity of the reagent in distinguishing between surface chemical properties. The reaction may be chemical, physical or a combination of those types. This process is referred to herein as "conditioning". An especially useful apparatus for such "conditioning" involves applying the conditioning agent to the particles while they are on a horizontally extending vibrating surface which contains a vertical extending barrier to form a pool of the conditioning agent.
Methods of particle separation in which it is necessary to condition the particles include flotation separation and optical separation. In flotation separation, the particles to be separat-ed are conditioned with a flotation agent, which coats the ore particles with which it is reactive and creates a hydrophobic mineral surface. When air bubbles are attached to this hydrophobic surface, the coated particles can be floated away from uncoated particlesO
For an optical separation, the mixture of particles can be conditioned with a suitable surface-selective reagent and either a coloring agent or a fluorescent material, depending upon the nature of the separation process.
The procedure for applying a coating to ore particles for an optical separation usually involves application of the fluorescent or coloring agent iIl one of three forms: pre-cipitated in an aqueous or non-aqueous slurry, dissolved in an organic conditioning reagent (which may be then dispersed in an aqueous medium prior to application)~ or direct application of the agent (either alone, in solution, or dispersed in an aqueous medium) after a conditioning reagent has been applied to the particles.
A further known method describes the rendering of asbestos contained in a host rock diff~rentially fluorescent in relation to the rock. A fluorescent dye is precipitated to form a gelatinous sl~rry, into which the asbestos-containing par-ticles are dipped. Some quantity of the suspension is entrained in exposed asbestos fibers, giving those particles which contain more asbestos a higher fluorescene than the particles with less asbestos.
Various methods are known for selectively coating lime-stone particles, or gangue particles which do not contain major amounts of limestone, with a fluorescent dye. For selectively coating limestone, a carboxylic acid such as oleic acid or caprylic acid is used as the coupling agent. I~ it is desirable to coat the siliceous gangue particles, an aliphatic amine is used as the coupling agent. It is contemplated to either combine a fluorescent dye with the coupling agent prior to conditioning the ore particles or apply a fluorescent dye to the conditioned particles. However, a preferred method is to physically combine the coupling agent and fluorescent dye (e.g., by dissolving the dye in tall oil) prior to conditioning, both to realize a lower gye consumption and to simplify the process.
Examples of processes for the separation of oil shale particles are known. An example of a process for the separation of coal particles is also known.
A three-step process is known for applying a fluorescent coating to mineral particles, involving a preconditioning by wash-ing with water plus a wetting and a scouring agent, treating with a collector ("second conditioning"), and finally applying the fluorescent reagent.
The selection of conditioning agents and coloring or fluorescing agents is o~ utmost importance in developing a sorting process for a particular ore, utilizing one or the previously described system.
Excluding one known method which is a purely mechanical entrainment of fluorescent dye suspension by asbestos fibers, other known methods use mixtures of coupling agents (which select-ively bond to the desired ore particles) with Eluorescent or color-ing agents or sequentially apply a coupling agent and a mutually compatible fluorescent or coloring agent. When mixtures are contem-plated, they comprise either solutions or dispersions (including emulsions) of coupling agent and fluorescent or coloring agent in an aqueous or organic carrier, depending upon the nature of the components.
Ordinarily, the coupling agent and the fluorescent or coloring agent are both insoluble in water so that subsequent steps, such as rinsing to remove the wea~ly adhering coating from undesired ore particles, will not greatly remove the coating from desired particles. The control of rinsing or washing conditions can significantly improve the selectivity of a separation. How-eve, if it is desired to provide a dye to particles which are selectively non-coated with the coupling agent to the substantial -- 5 ~
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exclusion of the coated particles, a water insoluble coupling agent and a water soluble dye, or a water soluble coupling agent and a water insoluble dye can be used.
Such contact between aqueous media and water-insoluble materials can result in the unwanted formation of emulsions.
Emulsions which ~orm can be particularly difficult to remove, since the fine ore particles which are produced during crushing to the desired size range cannot always be completely removed by pre-washing, and these particles are incorporated into the emulsions, thereby in-creasing the emulsion stability. This has the effect of causingdifficulties in the handling of process streams and preventing the recycling of materials in the process.
The preparation of the choleretics having the formula Ar-CO-~CH2~nCOOH, in which Ar is either fluoranthyl or tetrahydro-fluoranthyl, and n is 2 or 3 is known. Similar derivatives of fluoranthene in which the ~C~2)n function is expanded to include bivalent, aliphatic hydrocarbon radicals containing up to 8 carbon atoms are also known. These are examples of fluorescent molecules ~fluoranthene and tetrahydrofluoranthene) which have been provided with specific functional ~roups (carboxy and oxocarboxy)~ Such compounds, and the processes for their preparation, can be useful in the practice of the present invention.
The present invention relates to separation of at least one type of particle from a mixture of particles and especially comprises a process for separating a first type of particle ~L~6~
1 (e.g. ore particles) from a second type (e.g. gangue particles), comprising the steps of:
a. conditioning the particles with a conditioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively mark (e.g., coat) either i. at least a portion of ~he first type of particle or ii. at least a portion of the second type of particle to the substantial exclusion of the other;
b. detecting the marked particles; and c. separating the detected, marked particles from the substantially unmarked particles.
As used herein the term "particle" includes any solid object of a size which can be separated by manpower or by machine from other similarly sized objects. This process includes separating relatively higher grade ore particles rom relatively lower grade ore particles (wherein the relatively lower grade particles are considered as "gangue"~.
The ~erm 'Isubstantial exclusion", as used herein, means a sufficient difference in the degree or nature of the marking (e.g., coa~ing) on the relative types of particle (e.g., ore or gangue) to enable a difference in detection, either visually or by a detection device (e.g~ photo-multiplier, Geiger-counter etc.), of the detectable moiety sufficient to be useful in separating the types of marked particle.
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l The term "substantially non-fluorescing" as used herein means tha~ at a particular wavelength or waveband - there is a sufficiently lower degree of fluorescence (e.g~, intensity of radiation or luminous flux) from a given particle to enable separation of said particle from particles having a higher degree of fluorescence at said wavelength or waveband.
Rccording to the present invention, there is provided a process for the separation of higher grade ore particles from lower grade ore particles and/or gangue particles, in which the particles are subjected to a conditioning step wherein the conditioning agent comprises a comp~und having both a surface-selective functional group and a detectable (e.g., fluorescent), moiety, causing the desired frac~ion of the particles to become selectively marked (e.g., coated) with the agent to the substantial exclusion of the other fraction or fractions, irradiating the mixture of particles to cause fluorescence in the marked particles so that they may be distinguished from the unmarked particles, and separating the fluorescing, marked particles from the substantially unmarked particles. The invention also comprises certain novel compositions of matter and the processes for their preparation.
~5 The fraction of particles which is selectively coated can be either the higher grade material or the lower grade material, as determined by the choice of conditioning agent.
Instead of fluorescence, other detectable properties may be imparted to the coated particles, including radio-activity, visible color, or the ability to exhibit charac-teristics properties upon stimulation by external electro-magnetic radiation, subatomic particles or chemical reactions, by choice of a detectable m~iety having the desired property.
A process and apparatus is known for the separation of a mixture of particles containiny differing concentrations of a selected component into first, second and third fractions.
The known process comprises the steps of:
a. conditioning the mixture of particles with at least one surface-active agent selected from compounds providing hydrophobic coatings and compounds providing hydrophilic coatings and having an affinity toward a selected component in the particles such that the surface-active agent selectively adheres to the selected component in the particles for providing a coating on the particles dependent upon the concentration of the selected component in the particles to the substantial exclusion of coating particles containing no appreciable concentration of the selected component, in combination with providing at least one fluorescent dye selected from hydrophobic and hydrophilic fluorescent dyes to said particles, which fluorescent dye couples with the surface-active agent coating when the fluorescent dye and the surface-active agent have the same hydrophobic or hydro-philic character and which fluorescent dye coats the particles in areas not coated by the surface-active agent when the fluorescent dye and surface-active agent have different hydrophobic or hydrophilic character;
b. irradiating the conditioned particles to excite and induce fluorescence of the fluorescent dye to a degree sufficient to distinguish among the intensities of fluorescence (or luminous flux) of the coatings on the particles; and c. separating the particles into three fractions by distinguishins- among the intensities of fluorescence of the provided fluorescent dye on the particles, with a first _ g _ ~6~
1 fraction comprising particles exhibiting a relatively high intensity of fluorescence, a second fraction comprising particles exhibiting a relatively lower intensity of fluorescence than particles in the first fraction and a third fraction comprising particles exhibiting a relative by lower intensity of fluorescence than particles in the second fraction.
The word "intensity", as used herein includes not only the scientific meaning of magnitude per unit (e.g., area) but also the broader concept of degree of strength of a property (such as photon emission) including detection of luminous flux.
The present invention includes separation of a mixture of particles (especially ore particles) containing differing surface concentrations of a selected component ~e.g., a particular mineral or ion) into first, second and third fractions, by a process comprising the steps of: 0 a~ conditioning the mixture of particles with at least one surface-active agent comprising a compound having both a selective functional group and a detectable moiety and having an affinity toward a selected component in the particles such that the surface-active agent selectively adheres to the selected componen~ in the particles to provide a coating on the particles dependent upon the concentration of the selected component in the particles to the substantial exclusion of coating particles containing no appreciable concentration of the selected component; and b. separating the conditioned particles into three fractions by distinguishing ~he degree of the detectable moiety on the surface of the conditioned particles, with a first fraction comprising particles exhibiting a relatively 1~6~
1 high surface content of said moiety, a second fraction comprising particles exhibiting a relatively lower surface content of said moiety than particles in the first fraction and a third fraction comprising particles exhibiting a relatively lower content of said moiety than particles in the second fraction.
When each of two particles being compared have a face of similar total area, the term "surface content" refers to that portion of the surface area of each such face upon which the surface active agent has adhered. When the faces being compared have greatly differing surface area, the "relative surface content" of each is generally determined as the relative fraction of the surace area of the face upon which the surface active agent adhered.
In any event either a detectable difference in the marked surface area of at least one face of each of two particles can be used to effect separation or with par-ticles of greatly differing surface area (and thus greatlydiffering mass) the proportion of marked area to unmarked area can be used to detect differing con`centration of a desired substance.
Detail ~ ion of the Invention The process of the present invention is based upon those differences which exist in the surface chemical properties of the various components present in ores.
Due to these differences, there can be selected a surface-selective agent or a mixture o surface-selective agents which will effectively and selectively coat only certain components present in an ore. A separation based upon providing a distinctive marking based on surface chemical properties provides relatively more consistent separation ~6~
1 ~esults than do separation methods based upon other naturally-occurring properties, such as color, reflectance - and conductivity. Such other properties in nature, generally -tend to be substantially similar for the various components of an ore, such that a fine degree of resolution is required in order to distinguish between these properties for the various materials present in an ore. Such a fine degree of resolution may be difficult to obtain and, for this reason, the efficiency of separation based upon these naturally occurring properties suffers.
In the practice of the method of this invention with regard to a particular mineral ore, the ore is first subjected to a cr~shing step. In this crushing step, the lS ore is crushed to physically separate the components present within the ore. For example, some ores exist with stratifications and/or pockets of various components and crushing of the ore as mined is a means for physically separating these stratifications and/or pockets. Crushing also increases the surface area of the particles, thereby providing a greater reactive site with which the surface-selective agent can react. The ore is crushed, typically to a par~icle size of from about one-quarter inch to about eight inches. Particle sizes of less than one-quarter inch can be ~sed in the practice of this invention.
However, such sizes require greater amounts of surface agent and are more difficult to separate, requiring greater amounts of time for separation for a given mass of ore.
Particle sizes of greater than eight inches can be used in -30 the practice of this invention but generally such particle sizes entrain such a substantial mixture of components that separation efficiency decreasesO It is preferred to use ore particles of a size rom about one-half inch to about three inches. Following the crushing and sizing steps, the ore particles can be deslimed to remove soluble impurities and surface fines which can be present on the particulate ore.
The ore is conditioned following sizing with a surface-selective agen-t or a mixture of surface-selective agents that sel-ectively adheres to one of the components present in the ore to the substantial exclusion of adhering to the other components pres-ent or which undergoes characteristic chemical reaction with a given component of the ore, as does 8-hydroxyquinoline with magne-sium ores (such as talc). The surface-selective agent is used in sufficient quantity to provide a thin film on the components of the ore towards which the surface-selective agent is reactive. Due to the surface chemical property of the components the surface-selective agent only coats or only reacts with the selected com-ponents within the ore.
The ore is conditioned with the surface-selective agent by mixing the surface-selective agent in a surface reactive rel-ationship with the particulate ore. Conditioning of the ore with the agent is accomplished by contacting the particulate ore with the surface-selective agent. Many techniques are available for contacting a particulate solid with a liquid reagent. Such tech-niques include dipping the solid particles into a liquid bath con-taining the surface-selective agent, spraying the surface-select-ive agent onto the solid particles, mixing the solid particles with the surface-selective agen-t, and the like. It is preferred to spray the sized ore with the liquid reagent. Spraying tech~
niques include, but are not limited to, spraying onto the ore as the ore passes the spray nozzle on a vibrating screen or belt, or spraying the ore as it passes through a ring sprayer or a series of ring sprayers.
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l The surface-selective agent can be used in any suit-able manner such as in solution, suspension, dispersion, or by itself. It is preferred to form a solution or dispersion of the surface selective agent in water. Such a solution or dispersion can be readily coated on the ore particles and water is an economical and readily available carrier. The particulate ore is passed through such an aqueous bath to condition the ore with the surface-selective agent. In the bath the surface-selective agent interacts with those particles of the ore having surface chemical properties that are receptive to the surface-selective agent. Following the a~euous bath, the particu-late ore is washed with an aqueous wash to remove excess surface-selective agent, weakly adhering surface-selective agent and any surface-selective agent entrained within the particulate ore. In some cases, it is possible to eliminate the washing step if the conditioning bath is sufficiently dilute.
Some gradation in the amount of coating on the par-ticles is normally observed, due to the nonhom~geneity which is common to naturally occurring ore deposits. Typically, the crushing operation will not completely free the desired ore component from the gangue: particles will range in composition from nearly pure ore to nearly pure gangue material, including various mixtures of the components.
If the surface-selective agent is chosen for ore coating, the higher grade ore particles will be more heavily coated than the lower grade ore particles, and the more pure gangue particles will be substantially uncoated.
Conversely, should the surface-selective agent be chosen to coat the gangue, the gangue particles will be more heavily coated than the lower grade ore particles, and the higher grade ore particles ~ill remain ~ubstantially uncoated.
- 15 - Reg. No. 013/729-80 1 The relative degree of particle coating is usually related to the surface area in a given particle attribut-able to that component which is reactive toward the chosen surface-selective agent A particle having a relatively higher percentage of the desired component will generally also have a relatively higher percentage of exposed surface area of that component, and will therefore accept a rela-tively larger amount of surface-selective agent.
To distinguish between the coated particles and the uncoated particles, the surface-selective agent chosen con-tains a detectable component such as a radioactive atom, a chromophore or a fluorescent moiety. The detectable com-ponent can also comprise a moiety which can be detected after further chemical reaction, as by exposure to radia-tion such as heat or light, pH changes, or redox reaction.
The ore can then be sorted by radiation detection, by visible optical means or by irradiation with electromagnetic radiation to induce fluorescence. In the latter case, the ~luorescent surface-selective agent which coats some of the particles fluoresces, while the uncoated material does not fluoresce to any substantial degree. The different materials can be separated, based upon this property. It is also possible to separate various grades of ore, based upon the knowledge that the more heavily coated particles will possess a more intense color or fluorescence than will the less heavily coated particles. Conversely, a sur~ace-selective agent can be used which will block ultraviolet radiation or which will absorb rather ~han reflec$ light.
If a mechanical device is used to effect the separation, adjustment Qf the machine's sensitivity will alter the grade of ore product which is obtained.
1 The term "gangue" is used herein to include any mineral or assemblage of minerals other than that which is considered to be "ore" in a given separation procedure.
- In many instances, the gangue material contains minerals of economic interest, and therefore is not a discarded waste material, but may be subjected to a subsequent separation process which uses an agent having the ability to selec-tively coat an additional component. Should the recovery of other components be desired, futher separations using different reagents may be used. From this, it can be seen that the terms "ore" and "gangue" have meaning only in terms of a specific separation to be performed: ore in a separation may be a component of the gangue from a previous separation.
Similarly, subsequent separation steps may be used to further separate the components of an "ore" fraction resulting from a procedure. This technique is useful in cases where a very pure ore mineral is desired and the additional expense of repeated processing to remove various impurities in a step-wise manner is not prohibitive, or in cases where a single surface active agent does not provide the required selectivity for the desired separation to be conducted in one step. The term "ore" may be applied, therefore, to material which yields an ore fraction and a gangue fraction in a later separation.
Generally, fluorescence refers to the property of absorbing radiation at one particular wave-length and simultaneously re-emitting light of a different waveleng~h so long as the stimulus is active. It is intended in the present method to use the term "fluorescence" to indicate that property of absorbing at one par~icular wavelength and re-emitting it at a different wavelength, whether or not visible, during exposure to an active stimulus or after exposure or during both these time periods.
1 Thus, fluorescence is used generically herein to include fluorescence, phophorescence, and envisions the emission of electromagnetic waves whether or not within the visible - spectrum.
Electromagnetic radiation generally referes to the emission of energy waves of all the various wavelengths encompassed by the entire electreomagnetic spectrum. It is intended in the present method to use the term electro-magnetic radiation to indicate any and all stimuli thatwill excite and induce fluorescence of the fluorescent dye.
Thus, electromagnetic radiation is ~sed generically herein and envisions other stimuli that will excite and induce fluorescence of the fluorescent marking agent. If a property other than fluorescence is to be detected, external influences such as heat, radioactivity, or chemical stimuli, including oxidation, reduction, pH changes or salt formation can be utilized in producing a detectable property in the surface-selective agent.
If is preferable, but not essential, that the surface selective marking agent be soluble in water to avoid the potential problems of emulsion formation within the system.
This can be accomplished ~ith the normally water insolu~le longer-chain organic compo~nds by utilizing their salts, especially alkali-metal salts, as surface-selective agents.
If the marking agent is not water soluble (or only slightly water soluble) it can be applied as an aqueous dispersion (or emulsion) or in a non-aqueous solvent.
A further embodiment, which is considered to be within the scope of this invention, is the application of the fl~ore-scent surface-selective agent to the particles in a dry state, e.g. "dusting" the particl~s with the agent. This can be accomplished either with or without an external driving force which facilitates the desired reaction - i ~6~
1 between ~he agent and the surface of the particles, s~ch as a techniq~e analogous to electrostatic spray painting, in which an electrical charge would be imparted to the agent - and an electrical charge of the opposite polarity given the particles, prior to the coatin~ operationO
The selection of the surface-selective functional group in a fluorescent surface-selective agent is directed by the properties of the mineral species which are to be selectively coated by the agent, and the properties of the other species which are present in the mixture of particles.
Reaction of the surface-selective functional group with a mineral surface, resulting in a physical adsorption or the formation of a new surface compound by chemical bonding is a likely mechanism by which the fluorescent moiety is attached to the surface of a particle.
The following table lists typical surface-selective compounds:
Type Formula phenol R-ONa xanthate ROCSSNa 25 dithiophosphate IRO)2PSSNa dithiocarbamate R2NCSSNa thiol (mercaptan) RSH
thiocarbanilide (RNH)2CS
carboxylic acid salt RCOONa 30 arenesulfonate or alkylarenesulfonate RSO3Na alkyl or aryl sulfate ROSO3Na primary amine salt RNH3+X-quaternary ammonium ~al~ RN(CH3)3~x 35 alkylpyridinium salt RCsH4N.H+X~
amine and amine salts RnNH3-n, where n = 1, 2 or 3 6~ L6 -- lg ~
1 In the above table, the free acid, or hydrogen, form can be used, but in most cases (especially with the dithiophosphates, phenols, xanthates and dithiocarbamates) - the salt form is preferred and is so indicated in the table.
Wherein Na appears in the above formulae, it may be replaced by any of the alkali metals (e.g., K) if water solubility is desired, by an alkaline earth metal if oil solubility is needed, or by a transition metal such as aluminum or iron if a more insoluble compound is required for use in a dispersion. X~, as used in the table above is an anionic group, such as halide (e.g., Cl), sulfate, sulfonate, carboxylate, etc.
The R in the above formulae is a group which contains a detectable moiety. The table provides a representative, though not exhaustive, list of the useful surface-selective groups which are contemplated in the present invention.
R can be selected from such types of groups as poly-nuclear aromatics (including fluoranthene), the groups in xanthene dyes (fluorescein, rhodamine, etcO) in dyes used for fabric whitening (coumarin derivatives, diamino-stilbenedisulfonic acid-cyanuric chloride, distyrylbiphenyl, naphthotriazolystilbene, pyrazoline) and many other fluore-scent groups.
An especially useful class of pheno~s is the hydroxy-quinolines of general formula Na~~0 ~ ~ where the oxygen can be on any carbon atom, but preferably is in the8-position (e.g~, 8-hydroxyquinoline, which is especially useful for marking magnesium compounds) and where additional substituents (e.g., halide, carboxylate, sulfate, sulfonate, -- ~o --1 alkyl, aryl, etc.~ and similar condensed ring heterocyclic compounds (including 3,4 or 5 condensed rings) containing at least one heteronitrogen atom and at least one hydroxyl - group (e.g., the hydroxyquinazolines and hydroxyquinoxalines such as the sodium salt of 3-hydroxy-2-quinoxylinecarboxylic acid). The use of 8-hydroxyquinoline to mark magnesium-containing minerals on the surface of an ore is an example of the use of a chemically reactive, bifunctional marking agent, i.e., one containing a surface-selective group (e.g., the oxygen anion) and a detectable moiety which undergoes a chemical transformation which aids in detecting the marking agent when combined with a specific component of an ore (e.g., a magnesium compound). That is, the 8-hydroxyquinoline can be induced to fluoresce at a charac-teristic waveband or wavelength when it is combined with amagnesium mineral. In-general, the hydroxyquinol~ines are useful in marking polyvalent metal ions in a mineral (especially divalent and trivalent ions).
In some cases, the fluorescent moiety may be separated from the surface selective group by a alkylene chain or other linking group. Since it is known that the structural features of such a linking group can influence the surface-selective properties of the surface-selective end groups, the linking group could be considered as part of the surface selective group, Unsaturation in such a group could also contribute to the fluorescent properties and thereby be considered part of the fluorescent moiety. Thus the alkali metal salts (e.g., potassium) of fluorescent unsaturated carboxylic acids are contemplated as useful.
The fluorescent moiety might also contain the surface selective groups, as in 7-diethyamino-4-methylcoumarin salts. The practice of the invention does not necessitate that the detectable and surface-selective moieties be separate and readily distinguishable, al~hough that may be the case in a large number of fluoresc~nt surfactants.
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For the practice of this invention, the primary requirement is that the detectable surface-selective agent attaches to the surface of a particle~ Such surfactant types as cationics, anionics, nonionics, amphoterics, chelates, etc. can be used to advantage.
A variety of techniques are known in the practice of separations for increasing the selectivity of a collector. These techniques usually involve the use vf modifying agents in combin-ation with the collector, to influence the attachment of the collector onto the mineral surface. This invention relates to the selective attachment of surface-selective agents to mineral surfaces, and those techniques are included within the scope of this invention.
The use of pH regulating agents, activators, depressants, disper-sants, flocculants, and the like in combination with detectable surface-selective agents to achieve a desired selectivity is contemplated.
A further explanation of the invention is made by means of the followin~ examples, which are not intended to be limiting, the scope of this invention being defined by the appended claims.
Example I
After being informed that coworkers had discovered that limestone in the presence of silicate minerals can be selectively coated with a mixture of a carboxylic acid and a fluorescent dye;
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carboxylic acid derivatives of fluoranthene were prepared using the following reaction I:
/ C l. AlCl 1l I F - H + (CE~2)n o 3> F - C(cH2)n COOH
\ C / 2. ag.H+
o in which F - H is fluoranthene, Cl6Hlo, and n is 2, 4 or ~-Portions o~ each product were reduced with hydrazine according to the following reaction II:
II F C (C 2)n 2 4 ~ F ~ (CH2)n+l COOH + N2 Since the free carboxylic acids as formed are insoluble in wa-ter,each product from I and II was converted to its sodium salt by reaction with sodium hydroxide.
Each of the six salts was dissolved in water and pieces of limestone ore were dipped into the solutions, then the pieces were irradiated with ultraviolet light. All of the compounds were found to coat the limestone in the particles, bu-t the salts corres-ponding to -the formulae where n equals two were found to be the more selective in not coating silicate minerals. In each case, the reduced compounds derived from reaction II exhibited a higher rluorescence intensity estimated visually, than the precursor from reaction I.
Based upon the above, and the superior solubility and rinsing characteristics exhibited, 4-(fluoranthyl)-butanoic acid, F ~ (CH2)3 COOH, was selected for further testing in the separa-tion of lime~tone from siliceous gangue.
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1 The example is typical of the procedure which is followed in selecting a fluorescent surface-active agent for use in selectively coating a given component of a - mixture of ore particles.
Example II
A 2000 ml round bottom flask was charged with lOOg of fluoranthene, 529 or succinic anhydride and 1 liter of 2-nitropropane. The mixture was stirred and 157 9 of aluminum chloride was added slowly, whereupon the tempera-ture rose to about 50C, then cooled to room temperature and stirred over a weekend.
The reaction mixture was hydrolyzed by pouring slowly into about 1 liter of about 3N hydrochloric acid. Steam distillation was used to remove the solvent, and the solid residue was isolated by filtration with water washing. After transferring to a Soxhlet extractor, the solid was extracted into acetone.
The acetone extract was concentrated by distillation and 250 ml of deionized water was added, forming a slurry which dissolves after 800 ml of 2.5% sodium hydroxide was added. Upon acidification, the 4-(fluoranthyl)-4-oxobut anoic acid product precipitated and was collected by filtration. The product was partially dried under vacuum.
A 1000 ml flask was charged with 1189 of the partially dried product, above, and 43.79 of potassium hydroxide, 39 ml of hydrazine hydrate, and 375 ml of diethylene glycol were added. The mixture was stirred and heated, during which excess water and hydr~zine were collected and removed by means of a Dean-Stark trap, to a final temperature of ~6~ 6 1 about 195C, and maintained at that temperature for about eight hours. After cooling and slurrying with 1500 ml of about 1.5N hydrochloric acid, the 4-(fluoranthyl)-butanolc acid product was isolated by filtration and dried in a desiccator.
Example III
A portion of the product from Example II was used, in a pilot plant based upon the apparatus of U.S. Patent 3,472,375, for the separation of limestone from siliceous gangue. The 4-(fluoranthyl)-butanoic acid was converted to its sodium salt, which was dissolved in water to form a 0.1% by weight solution, and applied to the mixed ore and gangue particles by spraying. Following a rinse to remove excess reagent, the particles were passed through an electro-optical sorter which ejected the selectively coated ore particles to separate them from the substantially un-coated particles.
Six runs, totalling 1655 lb. of a limestone feed, weremade using the fluorescent surface-active agent. The feed material was obtained from a manufacturer of portland cement, and consisted o reject material from a hand sorting of limestone ore, having the average analysis 87D40% CaCO3, 7. 38~ MgCO3, 0.45% Fe2O3 and 5.17~ SiO~.
The following results were obtained from these six runs, showing the concentrating of limestone feed by impurity removal:
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1 As shown above, the limestone concentrate in each r~n was upgraded to between 88.51 and 90.90% CaCO3. Significant amounts of iron and silica remained in the waste stream particles. Considerable variability was noted in the results between runs, attributable to the inhomogeneous nature of the ore particles and the relatively small (186 to 359 lb.) quantities of material which were processed in each run.
Example IV
To prepare a fluorescent surface-selective agent for use in further separation testing, the procedure of Example II was repeated on a larger scale, as follows:
a 12 liter reactor was placed in an ice bath, and 5 liters of 2-nitropropane, 7009 of fluoranthene and 3659 of succinic anhydride were added. After cooling the mixture to about 10C, small portions of anhydrous aluminum chloride (totalling 1194g, over a one hour period) and an additional
This invention relates to compounds which contain both a surface-selective functional group and a detectable moiety, such as one which will fluoresce under ultraviolet light, and the use of such compounds in selectively marking, as by coating, certain components of a mixture of ore particles to the substantial exclusion of other particles. The detectable portion can have a visible color, can fluoresce, can emit radiation, or can be induced (as by further chemical reaction or exposure -to electro-magnetic radiation or sub-atomic particles~ to exhibit a charac-teristic property. The invention is particularly well suited foruse with a mechanical apparatus for sorting ore particles, such as an electro-optical separator.
A known method describes concentrating ore which involves preferentially coating the desired particles with a li~uid fluore-scent material, subjecting the ore to electromagnetic radiation so that at least the coated portion will fluoresce, and sensing the - ~l16~
characteristic fluorescent wavelength emitted by the irradiated particles.
An apparatus is known which senses the emitted fluorescent radiation from gangue or ore particles, especially coated particles, and separates by selectively directing streams of a fluid to cause those fluorescent particles to be removed from the remaining quantity of undesired ore.
A further process and apparatus are known which are similar to those previously described. Successful operation of a mechanical sorting device in such known apparatus is dependent upon the ability to selectively coat ~or otherwise mark) either gangue or ore particles which contain a particular mineral component, while not coating (or marking) the other particles to a significant extent. The surface chemical properties of a specific ore or gangue particle depend upon the minerals which are present in that particle and, since the composition of individual particles can show a wide variation, the surface chemical properties of the particles will also vary.
To utilize a difference in surface chemical properties in the separation of ore particles, it is necessar~ to contact the mixture of particles with a surface-selective agent which will selectively react with certain mineral species present in the particles, due to the selectivity of the reagent in distinguishing between surface chemical properties. The reaction may be chemical, physical or a combination of those types. This process is referred to herein as "conditioning". An especially useful apparatus for such "conditioning" involves applying the conditioning agent to the particles while they are on a horizontally extending vibrating surface which contains a vertical extending barrier to form a pool of the conditioning agent.
Methods of particle separation in which it is necessary to condition the particles include flotation separation and optical separation. In flotation separation, the particles to be separat-ed are conditioned with a flotation agent, which coats the ore particles with which it is reactive and creates a hydrophobic mineral surface. When air bubbles are attached to this hydrophobic surface, the coated particles can be floated away from uncoated particlesO
For an optical separation, the mixture of particles can be conditioned with a suitable surface-selective reagent and either a coloring agent or a fluorescent material, depending upon the nature of the separation process.
The procedure for applying a coating to ore particles for an optical separation usually involves application of the fluorescent or coloring agent iIl one of three forms: pre-cipitated in an aqueous or non-aqueous slurry, dissolved in an organic conditioning reagent (which may be then dispersed in an aqueous medium prior to application)~ or direct application of the agent (either alone, in solution, or dispersed in an aqueous medium) after a conditioning reagent has been applied to the particles.
A further known method describes the rendering of asbestos contained in a host rock diff~rentially fluorescent in relation to the rock. A fluorescent dye is precipitated to form a gelatinous sl~rry, into which the asbestos-containing par-ticles are dipped. Some quantity of the suspension is entrained in exposed asbestos fibers, giving those particles which contain more asbestos a higher fluorescene than the particles with less asbestos.
Various methods are known for selectively coating lime-stone particles, or gangue particles which do not contain major amounts of limestone, with a fluorescent dye. For selectively coating limestone, a carboxylic acid such as oleic acid or caprylic acid is used as the coupling agent. I~ it is desirable to coat the siliceous gangue particles, an aliphatic amine is used as the coupling agent. It is contemplated to either combine a fluorescent dye with the coupling agent prior to conditioning the ore particles or apply a fluorescent dye to the conditioned particles. However, a preferred method is to physically combine the coupling agent and fluorescent dye (e.g., by dissolving the dye in tall oil) prior to conditioning, both to realize a lower gye consumption and to simplify the process.
Examples of processes for the separation of oil shale particles are known. An example of a process for the separation of coal particles is also known.
A three-step process is known for applying a fluorescent coating to mineral particles, involving a preconditioning by wash-ing with water plus a wetting and a scouring agent, treating with a collector ("second conditioning"), and finally applying the fluorescent reagent.
The selection of conditioning agents and coloring or fluorescing agents is o~ utmost importance in developing a sorting process for a particular ore, utilizing one or the previously described system.
Excluding one known method which is a purely mechanical entrainment of fluorescent dye suspension by asbestos fibers, other known methods use mixtures of coupling agents (which select-ively bond to the desired ore particles) with Eluorescent or color-ing agents or sequentially apply a coupling agent and a mutually compatible fluorescent or coloring agent. When mixtures are contem-plated, they comprise either solutions or dispersions (including emulsions) of coupling agent and fluorescent or coloring agent in an aqueous or organic carrier, depending upon the nature of the components.
Ordinarily, the coupling agent and the fluorescent or coloring agent are both insoluble in water so that subsequent steps, such as rinsing to remove the wea~ly adhering coating from undesired ore particles, will not greatly remove the coating from desired particles. The control of rinsing or washing conditions can significantly improve the selectivity of a separation. How-eve, if it is desired to provide a dye to particles which are selectively non-coated with the coupling agent to the substantial -- 5 ~
5~
6~
exclusion of the coated particles, a water insoluble coupling agent and a water soluble dye, or a water soluble coupling agent and a water insoluble dye can be used.
Such contact between aqueous media and water-insoluble materials can result in the unwanted formation of emulsions.
Emulsions which ~orm can be particularly difficult to remove, since the fine ore particles which are produced during crushing to the desired size range cannot always be completely removed by pre-washing, and these particles are incorporated into the emulsions, thereby in-creasing the emulsion stability. This has the effect of causingdifficulties in the handling of process streams and preventing the recycling of materials in the process.
The preparation of the choleretics having the formula Ar-CO-~CH2~nCOOH, in which Ar is either fluoranthyl or tetrahydro-fluoranthyl, and n is 2 or 3 is known. Similar derivatives of fluoranthene in which the ~C~2)n function is expanded to include bivalent, aliphatic hydrocarbon radicals containing up to 8 carbon atoms are also known. These are examples of fluorescent molecules ~fluoranthene and tetrahydrofluoranthene) which have been provided with specific functional ~roups (carboxy and oxocarboxy)~ Such compounds, and the processes for their preparation, can be useful in the practice of the present invention.
The present invention relates to separation of at least one type of particle from a mixture of particles and especially comprises a process for separating a first type of particle ~L~6~
1 (e.g. ore particles) from a second type (e.g. gangue particles), comprising the steps of:
a. conditioning the particles with a conditioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively mark (e.g., coat) either i. at least a portion of ~he first type of particle or ii. at least a portion of the second type of particle to the substantial exclusion of the other;
b. detecting the marked particles; and c. separating the detected, marked particles from the substantially unmarked particles.
As used herein the term "particle" includes any solid object of a size which can be separated by manpower or by machine from other similarly sized objects. This process includes separating relatively higher grade ore particles rom relatively lower grade ore particles (wherein the relatively lower grade particles are considered as "gangue"~.
The ~erm 'Isubstantial exclusion", as used herein, means a sufficient difference in the degree or nature of the marking (e.g., coa~ing) on the relative types of particle (e.g., ore or gangue) to enable a difference in detection, either visually or by a detection device (e.g~ photo-multiplier, Geiger-counter etc.), of the detectable moiety sufficient to be useful in separating the types of marked particle.
- ~6~
l The term "substantially non-fluorescing" as used herein means tha~ at a particular wavelength or waveband - there is a sufficiently lower degree of fluorescence (e.g~, intensity of radiation or luminous flux) from a given particle to enable separation of said particle from particles having a higher degree of fluorescence at said wavelength or waveband.
Rccording to the present invention, there is provided a process for the separation of higher grade ore particles from lower grade ore particles and/or gangue particles, in which the particles are subjected to a conditioning step wherein the conditioning agent comprises a comp~und having both a surface-selective functional group and a detectable (e.g., fluorescent), moiety, causing the desired frac~ion of the particles to become selectively marked (e.g., coated) with the agent to the substantial exclusion of the other fraction or fractions, irradiating the mixture of particles to cause fluorescence in the marked particles so that they may be distinguished from the unmarked particles, and separating the fluorescing, marked particles from the substantially unmarked particles. The invention also comprises certain novel compositions of matter and the processes for their preparation.
~5 The fraction of particles which is selectively coated can be either the higher grade material or the lower grade material, as determined by the choice of conditioning agent.
Instead of fluorescence, other detectable properties may be imparted to the coated particles, including radio-activity, visible color, or the ability to exhibit charac-teristics properties upon stimulation by external electro-magnetic radiation, subatomic particles or chemical reactions, by choice of a detectable m~iety having the desired property.
A process and apparatus is known for the separation of a mixture of particles containiny differing concentrations of a selected component into first, second and third fractions.
The known process comprises the steps of:
a. conditioning the mixture of particles with at least one surface-active agent selected from compounds providing hydrophobic coatings and compounds providing hydrophilic coatings and having an affinity toward a selected component in the particles such that the surface-active agent selectively adheres to the selected component in the particles for providing a coating on the particles dependent upon the concentration of the selected component in the particles to the substantial exclusion of coating particles containing no appreciable concentration of the selected component, in combination with providing at least one fluorescent dye selected from hydrophobic and hydrophilic fluorescent dyes to said particles, which fluorescent dye couples with the surface-active agent coating when the fluorescent dye and the surface-active agent have the same hydrophobic or hydro-philic character and which fluorescent dye coats the particles in areas not coated by the surface-active agent when the fluorescent dye and surface-active agent have different hydrophobic or hydrophilic character;
b. irradiating the conditioned particles to excite and induce fluorescence of the fluorescent dye to a degree sufficient to distinguish among the intensities of fluorescence (or luminous flux) of the coatings on the particles; and c. separating the particles into three fractions by distinguishins- among the intensities of fluorescence of the provided fluorescent dye on the particles, with a first _ g _ ~6~
1 fraction comprising particles exhibiting a relatively high intensity of fluorescence, a second fraction comprising particles exhibiting a relatively lower intensity of fluorescence than particles in the first fraction and a third fraction comprising particles exhibiting a relative by lower intensity of fluorescence than particles in the second fraction.
The word "intensity", as used herein includes not only the scientific meaning of magnitude per unit (e.g., area) but also the broader concept of degree of strength of a property (such as photon emission) including detection of luminous flux.
The present invention includes separation of a mixture of particles (especially ore particles) containing differing surface concentrations of a selected component ~e.g., a particular mineral or ion) into first, second and third fractions, by a process comprising the steps of: 0 a~ conditioning the mixture of particles with at least one surface-active agent comprising a compound having both a selective functional group and a detectable moiety and having an affinity toward a selected component in the particles such that the surface-active agent selectively adheres to the selected componen~ in the particles to provide a coating on the particles dependent upon the concentration of the selected component in the particles to the substantial exclusion of coating particles containing no appreciable concentration of the selected component; and b. separating the conditioned particles into three fractions by distinguishing ~he degree of the detectable moiety on the surface of the conditioned particles, with a first fraction comprising particles exhibiting a relatively 1~6~
1 high surface content of said moiety, a second fraction comprising particles exhibiting a relatively lower surface content of said moiety than particles in the first fraction and a third fraction comprising particles exhibiting a relatively lower content of said moiety than particles in the second fraction.
When each of two particles being compared have a face of similar total area, the term "surface content" refers to that portion of the surface area of each such face upon which the surface active agent has adhered. When the faces being compared have greatly differing surface area, the "relative surface content" of each is generally determined as the relative fraction of the surace area of the face upon which the surface active agent adhered.
In any event either a detectable difference in the marked surface area of at least one face of each of two particles can be used to effect separation or with par-ticles of greatly differing surface area (and thus greatlydiffering mass) the proportion of marked area to unmarked area can be used to detect differing con`centration of a desired substance.
Detail ~ ion of the Invention The process of the present invention is based upon those differences which exist in the surface chemical properties of the various components present in ores.
Due to these differences, there can be selected a surface-selective agent or a mixture o surface-selective agents which will effectively and selectively coat only certain components present in an ore. A separation based upon providing a distinctive marking based on surface chemical properties provides relatively more consistent separation ~6~
1 ~esults than do separation methods based upon other naturally-occurring properties, such as color, reflectance - and conductivity. Such other properties in nature, generally -tend to be substantially similar for the various components of an ore, such that a fine degree of resolution is required in order to distinguish between these properties for the various materials present in an ore. Such a fine degree of resolution may be difficult to obtain and, for this reason, the efficiency of separation based upon these naturally occurring properties suffers.
In the practice of the method of this invention with regard to a particular mineral ore, the ore is first subjected to a cr~shing step. In this crushing step, the lS ore is crushed to physically separate the components present within the ore. For example, some ores exist with stratifications and/or pockets of various components and crushing of the ore as mined is a means for physically separating these stratifications and/or pockets. Crushing also increases the surface area of the particles, thereby providing a greater reactive site with which the surface-selective agent can react. The ore is crushed, typically to a par~icle size of from about one-quarter inch to about eight inches. Particle sizes of less than one-quarter inch can be ~sed in the practice of this invention.
However, such sizes require greater amounts of surface agent and are more difficult to separate, requiring greater amounts of time for separation for a given mass of ore.
Particle sizes of greater than eight inches can be used in -30 the practice of this invention but generally such particle sizes entrain such a substantial mixture of components that separation efficiency decreasesO It is preferred to use ore particles of a size rom about one-half inch to about three inches. Following the crushing and sizing steps, the ore particles can be deslimed to remove soluble impurities and surface fines which can be present on the particulate ore.
The ore is conditioned following sizing with a surface-selective agen-t or a mixture of surface-selective agents that sel-ectively adheres to one of the components present in the ore to the substantial exclusion of adhering to the other components pres-ent or which undergoes characteristic chemical reaction with a given component of the ore, as does 8-hydroxyquinoline with magne-sium ores (such as talc). The surface-selective agent is used in sufficient quantity to provide a thin film on the components of the ore towards which the surface-selective agent is reactive. Due to the surface chemical property of the components the surface-selective agent only coats or only reacts with the selected com-ponents within the ore.
The ore is conditioned with the surface-selective agent by mixing the surface-selective agent in a surface reactive rel-ationship with the particulate ore. Conditioning of the ore with the agent is accomplished by contacting the particulate ore with the surface-selective agent. Many techniques are available for contacting a particulate solid with a liquid reagent. Such tech-niques include dipping the solid particles into a liquid bath con-taining the surface-selective agent, spraying the surface-select-ive agent onto the solid particles, mixing the solid particles with the surface-selective agen-t, and the like. It is preferred to spray the sized ore with the liquid reagent. Spraying tech~
niques include, but are not limited to, spraying onto the ore as the ore passes the spray nozzle on a vibrating screen or belt, or spraying the ore as it passes through a ring sprayer or a series of ring sprayers.
.
l The surface-selective agent can be used in any suit-able manner such as in solution, suspension, dispersion, or by itself. It is preferred to form a solution or dispersion of the surface selective agent in water. Such a solution or dispersion can be readily coated on the ore particles and water is an economical and readily available carrier. The particulate ore is passed through such an aqueous bath to condition the ore with the surface-selective agent. In the bath the surface-selective agent interacts with those particles of the ore having surface chemical properties that are receptive to the surface-selective agent. Following the a~euous bath, the particu-late ore is washed with an aqueous wash to remove excess surface-selective agent, weakly adhering surface-selective agent and any surface-selective agent entrained within the particulate ore. In some cases, it is possible to eliminate the washing step if the conditioning bath is sufficiently dilute.
Some gradation in the amount of coating on the par-ticles is normally observed, due to the nonhom~geneity which is common to naturally occurring ore deposits. Typically, the crushing operation will not completely free the desired ore component from the gangue: particles will range in composition from nearly pure ore to nearly pure gangue material, including various mixtures of the components.
If the surface-selective agent is chosen for ore coating, the higher grade ore particles will be more heavily coated than the lower grade ore particles, and the more pure gangue particles will be substantially uncoated.
Conversely, should the surface-selective agent be chosen to coat the gangue, the gangue particles will be more heavily coated than the lower grade ore particles, and the higher grade ore particles ~ill remain ~ubstantially uncoated.
- 15 - Reg. No. 013/729-80 1 The relative degree of particle coating is usually related to the surface area in a given particle attribut-able to that component which is reactive toward the chosen surface-selective agent A particle having a relatively higher percentage of the desired component will generally also have a relatively higher percentage of exposed surface area of that component, and will therefore accept a rela-tively larger amount of surface-selective agent.
To distinguish between the coated particles and the uncoated particles, the surface-selective agent chosen con-tains a detectable component such as a radioactive atom, a chromophore or a fluorescent moiety. The detectable com-ponent can also comprise a moiety which can be detected after further chemical reaction, as by exposure to radia-tion such as heat or light, pH changes, or redox reaction.
The ore can then be sorted by radiation detection, by visible optical means or by irradiation with electromagnetic radiation to induce fluorescence. In the latter case, the ~luorescent surface-selective agent which coats some of the particles fluoresces, while the uncoated material does not fluoresce to any substantial degree. The different materials can be separated, based upon this property. It is also possible to separate various grades of ore, based upon the knowledge that the more heavily coated particles will possess a more intense color or fluorescence than will the less heavily coated particles. Conversely, a sur~ace-selective agent can be used which will block ultraviolet radiation or which will absorb rather ~han reflec$ light.
If a mechanical device is used to effect the separation, adjustment Qf the machine's sensitivity will alter the grade of ore product which is obtained.
1 The term "gangue" is used herein to include any mineral or assemblage of minerals other than that which is considered to be "ore" in a given separation procedure.
- In many instances, the gangue material contains minerals of economic interest, and therefore is not a discarded waste material, but may be subjected to a subsequent separation process which uses an agent having the ability to selec-tively coat an additional component. Should the recovery of other components be desired, futher separations using different reagents may be used. From this, it can be seen that the terms "ore" and "gangue" have meaning only in terms of a specific separation to be performed: ore in a separation may be a component of the gangue from a previous separation.
Similarly, subsequent separation steps may be used to further separate the components of an "ore" fraction resulting from a procedure. This technique is useful in cases where a very pure ore mineral is desired and the additional expense of repeated processing to remove various impurities in a step-wise manner is not prohibitive, or in cases where a single surface active agent does not provide the required selectivity for the desired separation to be conducted in one step. The term "ore" may be applied, therefore, to material which yields an ore fraction and a gangue fraction in a later separation.
Generally, fluorescence refers to the property of absorbing radiation at one particular wave-length and simultaneously re-emitting light of a different waveleng~h so long as the stimulus is active. It is intended in the present method to use the term "fluorescence" to indicate that property of absorbing at one par~icular wavelength and re-emitting it at a different wavelength, whether or not visible, during exposure to an active stimulus or after exposure or during both these time periods.
1 Thus, fluorescence is used generically herein to include fluorescence, phophorescence, and envisions the emission of electromagnetic waves whether or not within the visible - spectrum.
Electromagnetic radiation generally referes to the emission of energy waves of all the various wavelengths encompassed by the entire electreomagnetic spectrum. It is intended in the present method to use the term electro-magnetic radiation to indicate any and all stimuli thatwill excite and induce fluorescence of the fluorescent dye.
Thus, electromagnetic radiation is ~sed generically herein and envisions other stimuli that will excite and induce fluorescence of the fluorescent marking agent. If a property other than fluorescence is to be detected, external influences such as heat, radioactivity, or chemical stimuli, including oxidation, reduction, pH changes or salt formation can be utilized in producing a detectable property in the surface-selective agent.
If is preferable, but not essential, that the surface selective marking agent be soluble in water to avoid the potential problems of emulsion formation within the system.
This can be accomplished ~ith the normally water insolu~le longer-chain organic compo~nds by utilizing their salts, especially alkali-metal salts, as surface-selective agents.
If the marking agent is not water soluble (or only slightly water soluble) it can be applied as an aqueous dispersion (or emulsion) or in a non-aqueous solvent.
A further embodiment, which is considered to be within the scope of this invention, is the application of the fl~ore-scent surface-selective agent to the particles in a dry state, e.g. "dusting" the particl~s with the agent. This can be accomplished either with or without an external driving force which facilitates the desired reaction - i ~6~
1 between ~he agent and the surface of the particles, s~ch as a techniq~e analogous to electrostatic spray painting, in which an electrical charge would be imparted to the agent - and an electrical charge of the opposite polarity given the particles, prior to the coatin~ operationO
The selection of the surface-selective functional group in a fluorescent surface-selective agent is directed by the properties of the mineral species which are to be selectively coated by the agent, and the properties of the other species which are present in the mixture of particles.
Reaction of the surface-selective functional group with a mineral surface, resulting in a physical adsorption or the formation of a new surface compound by chemical bonding is a likely mechanism by which the fluorescent moiety is attached to the surface of a particle.
The following table lists typical surface-selective compounds:
Type Formula phenol R-ONa xanthate ROCSSNa 25 dithiophosphate IRO)2PSSNa dithiocarbamate R2NCSSNa thiol (mercaptan) RSH
thiocarbanilide (RNH)2CS
carboxylic acid salt RCOONa 30 arenesulfonate or alkylarenesulfonate RSO3Na alkyl or aryl sulfate ROSO3Na primary amine salt RNH3+X-quaternary ammonium ~al~ RN(CH3)3~x 35 alkylpyridinium salt RCsH4N.H+X~
amine and amine salts RnNH3-n, where n = 1, 2 or 3 6~ L6 -- lg ~
1 In the above table, the free acid, or hydrogen, form can be used, but in most cases (especially with the dithiophosphates, phenols, xanthates and dithiocarbamates) - the salt form is preferred and is so indicated in the table.
Wherein Na appears in the above formulae, it may be replaced by any of the alkali metals (e.g., K) if water solubility is desired, by an alkaline earth metal if oil solubility is needed, or by a transition metal such as aluminum or iron if a more insoluble compound is required for use in a dispersion. X~, as used in the table above is an anionic group, such as halide (e.g., Cl), sulfate, sulfonate, carboxylate, etc.
The R in the above formulae is a group which contains a detectable moiety. The table provides a representative, though not exhaustive, list of the useful surface-selective groups which are contemplated in the present invention.
R can be selected from such types of groups as poly-nuclear aromatics (including fluoranthene), the groups in xanthene dyes (fluorescein, rhodamine, etcO) in dyes used for fabric whitening (coumarin derivatives, diamino-stilbenedisulfonic acid-cyanuric chloride, distyrylbiphenyl, naphthotriazolystilbene, pyrazoline) and many other fluore-scent groups.
An especially useful class of pheno~s is the hydroxy-quinolines of general formula Na~~0 ~ ~ where the oxygen can be on any carbon atom, but preferably is in the8-position (e.g~, 8-hydroxyquinoline, which is especially useful for marking magnesium compounds) and where additional substituents (e.g., halide, carboxylate, sulfate, sulfonate, -- ~o --1 alkyl, aryl, etc.~ and similar condensed ring heterocyclic compounds (including 3,4 or 5 condensed rings) containing at least one heteronitrogen atom and at least one hydroxyl - group (e.g., the hydroxyquinazolines and hydroxyquinoxalines such as the sodium salt of 3-hydroxy-2-quinoxylinecarboxylic acid). The use of 8-hydroxyquinoline to mark magnesium-containing minerals on the surface of an ore is an example of the use of a chemically reactive, bifunctional marking agent, i.e., one containing a surface-selective group (e.g., the oxygen anion) and a detectable moiety which undergoes a chemical transformation which aids in detecting the marking agent when combined with a specific component of an ore (e.g., a magnesium compound). That is, the 8-hydroxyquinoline can be induced to fluoresce at a charac-teristic waveband or wavelength when it is combined with amagnesium mineral. In-general, the hydroxyquinol~ines are useful in marking polyvalent metal ions in a mineral (especially divalent and trivalent ions).
In some cases, the fluorescent moiety may be separated from the surface selective group by a alkylene chain or other linking group. Since it is known that the structural features of such a linking group can influence the surface-selective properties of the surface-selective end groups, the linking group could be considered as part of the surface selective group, Unsaturation in such a group could also contribute to the fluorescent properties and thereby be considered part of the fluorescent moiety. Thus the alkali metal salts (e.g., potassium) of fluorescent unsaturated carboxylic acids are contemplated as useful.
The fluorescent moiety might also contain the surface selective groups, as in 7-diethyamino-4-methylcoumarin salts. The practice of the invention does not necessitate that the detectable and surface-selective moieties be separate and readily distinguishable, al~hough that may be the case in a large number of fluoresc~nt surfactants.
~69~
For the practice of this invention, the primary requirement is that the detectable surface-selective agent attaches to the surface of a particle~ Such surfactant types as cationics, anionics, nonionics, amphoterics, chelates, etc. can be used to advantage.
A variety of techniques are known in the practice of separations for increasing the selectivity of a collector. These techniques usually involve the use vf modifying agents in combin-ation with the collector, to influence the attachment of the collector onto the mineral surface. This invention relates to the selective attachment of surface-selective agents to mineral surfaces, and those techniques are included within the scope of this invention.
The use of pH regulating agents, activators, depressants, disper-sants, flocculants, and the like in combination with detectable surface-selective agents to achieve a desired selectivity is contemplated.
A further explanation of the invention is made by means of the followin~ examples, which are not intended to be limiting, the scope of this invention being defined by the appended claims.
Example I
After being informed that coworkers had discovered that limestone in the presence of silicate minerals can be selectively coated with a mixture of a carboxylic acid and a fluorescent dye;
~698~L~
carboxylic acid derivatives of fluoranthene were prepared using the following reaction I:
/ C l. AlCl 1l I F - H + (CE~2)n o 3> F - C(cH2)n COOH
\ C / 2. ag.H+
o in which F - H is fluoranthene, Cl6Hlo, and n is 2, 4 or ~-Portions o~ each product were reduced with hydrazine according to the following reaction II:
II F C (C 2)n 2 4 ~ F ~ (CH2)n+l COOH + N2 Since the free carboxylic acids as formed are insoluble in wa-ter,each product from I and II was converted to its sodium salt by reaction with sodium hydroxide.
Each of the six salts was dissolved in water and pieces of limestone ore were dipped into the solutions, then the pieces were irradiated with ultraviolet light. All of the compounds were found to coat the limestone in the particles, bu-t the salts corres-ponding to -the formulae where n equals two were found to be the more selective in not coating silicate minerals. In each case, the reduced compounds derived from reaction II exhibited a higher rluorescence intensity estimated visually, than the precursor from reaction I.
Based upon the above, and the superior solubility and rinsing characteristics exhibited, 4-(fluoranthyl)-butanoic acid, F ~ (CH2)3 COOH, was selected for further testing in the separa-tion of lime~tone from siliceous gangue.
1~L6~
1 The example is typical of the procedure which is followed in selecting a fluorescent surface-active agent for use in selectively coating a given component of a - mixture of ore particles.
Example II
A 2000 ml round bottom flask was charged with lOOg of fluoranthene, 529 or succinic anhydride and 1 liter of 2-nitropropane. The mixture was stirred and 157 9 of aluminum chloride was added slowly, whereupon the tempera-ture rose to about 50C, then cooled to room temperature and stirred over a weekend.
The reaction mixture was hydrolyzed by pouring slowly into about 1 liter of about 3N hydrochloric acid. Steam distillation was used to remove the solvent, and the solid residue was isolated by filtration with water washing. After transferring to a Soxhlet extractor, the solid was extracted into acetone.
The acetone extract was concentrated by distillation and 250 ml of deionized water was added, forming a slurry which dissolves after 800 ml of 2.5% sodium hydroxide was added. Upon acidification, the 4-(fluoranthyl)-4-oxobut anoic acid product precipitated and was collected by filtration. The product was partially dried under vacuum.
A 1000 ml flask was charged with 1189 of the partially dried product, above, and 43.79 of potassium hydroxide, 39 ml of hydrazine hydrate, and 375 ml of diethylene glycol were added. The mixture was stirred and heated, during which excess water and hydr~zine were collected and removed by means of a Dean-Stark trap, to a final temperature of ~6~ 6 1 about 195C, and maintained at that temperature for about eight hours. After cooling and slurrying with 1500 ml of about 1.5N hydrochloric acid, the 4-(fluoranthyl)-butanolc acid product was isolated by filtration and dried in a desiccator.
Example III
A portion of the product from Example II was used, in a pilot plant based upon the apparatus of U.S. Patent 3,472,375, for the separation of limestone from siliceous gangue. The 4-(fluoranthyl)-butanoic acid was converted to its sodium salt, which was dissolved in water to form a 0.1% by weight solution, and applied to the mixed ore and gangue particles by spraying. Following a rinse to remove excess reagent, the particles were passed through an electro-optical sorter which ejected the selectively coated ore particles to separate them from the substantially un-coated particles.
Six runs, totalling 1655 lb. of a limestone feed, weremade using the fluorescent surface-active agent. The feed material was obtained from a manufacturer of portland cement, and consisted o reject material from a hand sorting of limestone ore, having the average analysis 87D40% CaCO3, 7. 38~ MgCO3, 0.45% Fe2O3 and 5.17~ SiO~.
The following results were obtained from these six runs, showing the concentrating of limestone feed by impurity removal:
13l6981G
--~5--_ C~ CO ~ ~ _ o l-. ~0 ~ ~r u~ Lr) Lr~ ~n ~ o o a: ~ O
a~ r- G~ ~D cn u~ ~ ~r ~ In o r h dP ) I_ o~ r` c~ r-- c7~ r-- c~ r- ~ ~_ .. __ _ _ .___ _ O~ _ C~ ~ ~ ~ C~ ~ ~ I_ ~D
aJ O . . . . . . . . . .
a) ,, er u~ ~ ul o~ . O a~ ~ o u~ u~ ~ ~ u~ ~ m ~D ~ n ~r ~ ~D
C
.
~ O a~ ~ co ~ u~ u~ ~D ~ In n ~ ~
~ ~ cc) - o a~ ~ ~ ~ ~ ~D ~ ~
O ~ ~ I~ _ co ~r u7 ~ ~ ~ ~ oo O
d~
_ O ~ I_ a~ ~ r- ~ ~ cn ~ I_ U ~ ~D ~ C~ ~ O ~ O r~ ~ ~-- ~
O ~: r- ~ ~ ~ ~ I_ ~ r~ ~ u~ ~r .
:~
Q
~ ~ ~ a:~ a~ . o o ~ tD cn ~ , V O . . o ~
~n c~ a~ o ~ ,~ ~ r~ a~ _ ~n ~r ~ co ~1 ~ r~ ~ ~ C~ ~ X _ c~ . I_ U
_ __ . . . .
v E c c c V
c) a o o o o o o :~ ~ U U ~ U U U U
v ~ ~ ~ ~ aJ a o u, aJ ~ ~ ~ ~ ~ a) ~ ~ ~ ~ 1 )J E u~ E~ u~ E u~ E ~n E ~n E~ u~
P~ W .,~ ~ rl ~ .,.~ ~ ~1 ~ rl ~ r~ ~
O ~ 3 ~ 3 ~ 3 ~:1 3 ~ ~1 3 _ , .
C o ~ - ~ ~ ~ ~o ~ O o o o o o o o; Z ~ ~ ~ ~ ~
. ~ _ __ ~ J
1 As shown above, the limestone concentrate in each r~n was upgraded to between 88.51 and 90.90% CaCO3. Significant amounts of iron and silica remained in the waste stream particles. Considerable variability was noted in the results between runs, attributable to the inhomogeneous nature of the ore particles and the relatively small (186 to 359 lb.) quantities of material which were processed in each run.
Example IV
To prepare a fluorescent surface-selective agent for use in further separation testing, the procedure of Example II was repeated on a larger scale, as follows:
a 12 liter reactor was placed in an ice bath, and 5 liters of 2-nitropropane, 7009 of fluoranthene and 3659 of succinic anhydride were added. After cooling the mixture to about 10C, small portions of anhydrous aluminum chloride (totalling 1194g, over a one hour period) and an additional
2 liters of 2-nitropropane were added. The temperature rose to about 20C during the ensuing reaction. After addition of the aluminum chloride, the bath was removed and the mixture stirred overnight. The mixture was hydrolyzed by the addition of one liter of 3N hydrochloric acid, and the solids recovered by filtration. Acetone was used to extract the solids in a Soxhlet extractor~ and the acetone solution was removed. ~fter the addition of 3.6 liters of deionized water, acetone was removed by distillation, and the remaining 4~(fluoranthyl~-4-oxobutanoic acid was removed by filtration, yielding a 1.8 Kg wet cake.
A 9059 portion of the wet cake was placed in a three-neck flask with 1.1 liter of diethylene glycol, 2.5 equi-valents of potassium hydroxide and 2.8 equivalents of 1 hydrazine hydrate. The mixture was heated to remove water and excess hydrazine, then the temperature was raised to 190C. After cooling, the mixture was poured into 3 liters of cold, lN hydrochloric acid, and the product, 4-(fluoranthyl)-butanoic acid dissolved in dilute sodium hydroxide solution, re-precipitated with aqueous hydro-chloric acid, and collected by filtration.
Example V
Pilot plant testing of the product from Example IV
yielded unsatisfactory results, apparently because the fluorescent compound did not properly coat the ore parti-cles. This was considered to be a result of significantlygreater than normal impurity levels in the compound.
A 200 g portion of the product from Example IV~was dissolved in 600 ml of toluene at a temperature near the boiling point of the solution. After decanting the solu-tion away from the dark, tar-like insolubles, it was cooled, and a small amount of a dark oil was removed.
The solution was contracted with two liters of 2.5% by weight sodium hydroxide solution in a separatory funnel, and the oryanic layer was discarded. The aqueous layer was acidified and the purified product was collected as a wet cake by filtration.
The pilot plant test of Example III was repeated, using the 4-~fluoranthyl)-butanoic acid purified above and feed material from the same lot as was prPviously used, yielding the following results for a total of 1228 lb. of limestone feed:
~6~ 6 J~ r~) [- ~ r~ c~ 1~ Q ~D ~ O
O . . . . . . . . . .
C~.--C~ : ~ ~ O ~ ~ ~ ~ O
CO 1~C~)~D 0 ~D ~ ~_Cr~ ~O` 1-h 5P
= ~ _._ _ N e~ ~~11`~ ~ t~ c~ ~ ~ ~ D
aJ O. . . .
~ ~ ~ O ~ ~ CO .-, CO ~ ~D O O~
ILI U~Il'~r ~ Iel~ Ln ~ t~ t7) ~D
~:
,~
. ~ _ o~ O O r~ ~ O Oa~ .
O . . . . . . . . . . .
N ~D ~)I_ ~ O~ . a~ O e~ ~Da~ ,_ O 1~ ~ ~D ~1 ~ 1`~ U~ O~ O~ a~
O
dP
_. ~1 ~ D CO N O O Lt') Il') (~ N 1~
O . . . . . . . . . ~ .
~,) o~ o a~ o o~ N ~ Ll~ u`) ~r l_ ~
O ~ 1-- N CO -- ~ ~ u~ ~ N t~ ~ ~D
.
:~
Q
s~ ~ ~ I_ I~ ~ r~ ~ a~ ~ ~ ~ ~
. . .
u~ ~ ~n ~ ~ I~ a~ o tn ~ ~ ~D t`
~_1 ~~ ~ O~ 1- ~ ~ ~ U~ u~ ~r C~ ~
.
E t.) u u u t) u C C C C C C
O O O O O O
t~ C~ C_~ ~, a~
O U~Q) ~~ ~ ~ ~Q~ ~ ~ ~ ~ ~
E ~q ~ ~o~ u~ E~ m E~ m .~1 ~.,~ ~ rl ~~ ~ .~ ~.,,1 O ~ :~ .:1 3 ~ 3 ~ 3 ~ S
~ ~ Ln ~D r~ c~
:S O N ~1 ~ N N N
~: Z _ _ _ ~ ~
__ 1~6~
1 This demonstrates that impurities in the fluorescent surface selective agent can influence its usefulness in selectively coating ore particles.
Example VI
Large-scale production of 4-(fluoranthyl3-butanoic acid was undertaken in a 1000 gallon glass-lined jacketed reactor, equipped with an agitator, into which 550 lb. of fluoranthene, 660 gallons of 2-nitropropane and 275 lb. of succinic anhydride was placed. A temperature of about 10C
was obtained by circulating cooling brine through the jacket, and then 811 lb. of aluminum chloride was added in 50 to 100 lb. aliquots over a period of about 3.5 hours, such that the temperature did not exceed 20C. A slight vacuum was used to remove oxides of nitrogen. The mixture was stirred overnight.
A quench solution was prepared in a 2500 gallon agitated, resin-lined vessel by adding 200 gallons of lON
hydrochloric acid to 200 gallons of water and 2000 lb. of ice. The reaction mixture, above, was added to the quench ~olution at a rate of about 10 to 15 gallons per minute, and an additional 7no lb. of ice was also added, resulting in a final temperature of abou~ 30C. This mixture was stirred for about two hours, forming a three phase slurry of solids dispersed in organic and agueous liquid phases.
About one-third o ~he solids were isolated by a slow filtration, yielding a very wet cake. Due to the highly unsatisfactory filtering rate, the solids and filtrate were returned to the quench vessel, and the organic solvent was removed by steam distillati~n. The remaining aqueous slurry filtered rapidly, yielding 958 lb. of wet solids.
, .
1 The solids were stirred into a solution containing two parts acetone to one part water, and sufficient sodium hydroxide to provide about 10~ in excess over that needed - to dissolve the 4-(fluoranthyl)-4-oxobutanoic acid prod~ct.
Insoluble tars were removed by filtration, and dilute hydrochloric acid was used to re-precipitate the acid prod~ct~ After filtration, the solids were subjected to an additional dissolution in base and precipitation with acid, as described above, resulting in a purified material.
A 109 lb. portion of the purified material was placed in the 1000 gallon jacketed reactor with about 45 gallons of diethylene glycol. The mixture was stirred and 46 lb.
of potassium hydroxide and 43 lb. of hydrazine hydrate were added. Steam was passed through the jacket to obtain a temperature of about 120C, and then the temperature was increased to 155C. A nitrogen purge was used to maintain an oxygen content less than about 1% and a distillation receiver was used to collect the water and excess hydrazine which distilled from the reactor.
After cooling to about 25C, the mixture was diluted with 110 gallons of water and acidified with 12 gallons of lON hydrochloric acid in about 50 gallons of water.
The solid 4-(fluoranthyl)-butanoic acid which formed was collected on a filter.
A sample of this product was tested in a pilot plant, as in Example III, using a different limestone ore feed material, and yielding the following results for a total of 406 lb. of feed:
.
o r~
o ~V o ~ ~ _ ~ o O ~ O~ CO ~ 0 O~ ~D
~ V
p~ dP
_ QJ ~ O O O O ~ ~
~ O ~ CO er ~D O a~
t U~ N 1` ~ 1-- 1~ 1`
.~
r~
O
O
~0 dP
~ c O
C ~ o cn O ~ ~ D
U~ O . . . . . .
o LO ~r a ~ ~D ~ U') Lr) V
_ _ _ t) CU
O o o U V
o v ~ ~ a u~
w o ~ 3 ~ 3 ~ ~
_ .
c ~
~; O ~ ~ ~r . _ .
A 9059 portion of the wet cake was placed in a three-neck flask with 1.1 liter of diethylene glycol, 2.5 equi-valents of potassium hydroxide and 2.8 equivalents of 1 hydrazine hydrate. The mixture was heated to remove water and excess hydrazine, then the temperature was raised to 190C. After cooling, the mixture was poured into 3 liters of cold, lN hydrochloric acid, and the product, 4-(fluoranthyl)-butanoic acid dissolved in dilute sodium hydroxide solution, re-precipitated with aqueous hydro-chloric acid, and collected by filtration.
Example V
Pilot plant testing of the product from Example IV
yielded unsatisfactory results, apparently because the fluorescent compound did not properly coat the ore parti-cles. This was considered to be a result of significantlygreater than normal impurity levels in the compound.
A 200 g portion of the product from Example IV~was dissolved in 600 ml of toluene at a temperature near the boiling point of the solution. After decanting the solu-tion away from the dark, tar-like insolubles, it was cooled, and a small amount of a dark oil was removed.
The solution was contracted with two liters of 2.5% by weight sodium hydroxide solution in a separatory funnel, and the oryanic layer was discarded. The aqueous layer was acidified and the purified product was collected as a wet cake by filtration.
The pilot plant test of Example III was repeated, using the 4-~fluoranthyl)-butanoic acid purified above and feed material from the same lot as was prPviously used, yielding the following results for a total of 1228 lb. of limestone feed:
~6~ 6 J~ r~) [- ~ r~ c~ 1~ Q ~D ~ O
O . . . . . . . . . .
C~.--C~ : ~ ~ O ~ ~ ~ ~ O
CO 1~C~)~D 0 ~D ~ ~_Cr~ ~O` 1-h 5P
= ~ _._ _ N e~ ~~11`~ ~ t~ c~ ~ ~ ~ D
aJ O. . . .
~ ~ ~ O ~ ~ CO .-, CO ~ ~D O O~
ILI U~Il'~r ~ Iel~ Ln ~ t~ t7) ~D
~:
,~
. ~ _ o~ O O r~ ~ O Oa~ .
O . . . . . . . . . . .
N ~D ~)I_ ~ O~ . a~ O e~ ~Da~ ,_ O 1~ ~ ~D ~1 ~ 1`~ U~ O~ O~ a~
O
dP
_. ~1 ~ D CO N O O Lt') Il') (~ N 1~
O . . . . . . . . . ~ .
~,) o~ o a~ o o~ N ~ Ll~ u`) ~r l_ ~
O ~ 1-- N CO -- ~ ~ u~ ~ N t~ ~ ~D
.
:~
Q
s~ ~ ~ I_ I~ ~ r~ ~ a~ ~ ~ ~ ~
. . .
u~ ~ ~n ~ ~ I~ a~ o tn ~ ~ ~D t`
~_1 ~~ ~ O~ 1- ~ ~ ~ U~ u~ ~r C~ ~
.
E t.) u u u t) u C C C C C C
O O O O O O
t~ C~ C_~ ~, a~
O U~Q) ~~ ~ ~ ~Q~ ~ ~ ~ ~ ~
E ~q ~ ~o~ u~ E~ m E~ m .~1 ~.,~ ~ rl ~~ ~ .~ ~.,,1 O ~ :~ .:1 3 ~ 3 ~ 3 ~ S
~ ~ Ln ~D r~ c~
:S O N ~1 ~ N N N
~: Z _ _ _ ~ ~
__ 1~6~
1 This demonstrates that impurities in the fluorescent surface selective agent can influence its usefulness in selectively coating ore particles.
Example VI
Large-scale production of 4-(fluoranthyl3-butanoic acid was undertaken in a 1000 gallon glass-lined jacketed reactor, equipped with an agitator, into which 550 lb. of fluoranthene, 660 gallons of 2-nitropropane and 275 lb. of succinic anhydride was placed. A temperature of about 10C
was obtained by circulating cooling brine through the jacket, and then 811 lb. of aluminum chloride was added in 50 to 100 lb. aliquots over a period of about 3.5 hours, such that the temperature did not exceed 20C. A slight vacuum was used to remove oxides of nitrogen. The mixture was stirred overnight.
A quench solution was prepared in a 2500 gallon agitated, resin-lined vessel by adding 200 gallons of lON
hydrochloric acid to 200 gallons of water and 2000 lb. of ice. The reaction mixture, above, was added to the quench ~olution at a rate of about 10 to 15 gallons per minute, and an additional 7no lb. of ice was also added, resulting in a final temperature of abou~ 30C. This mixture was stirred for about two hours, forming a three phase slurry of solids dispersed in organic and agueous liquid phases.
About one-third o ~he solids were isolated by a slow filtration, yielding a very wet cake. Due to the highly unsatisfactory filtering rate, the solids and filtrate were returned to the quench vessel, and the organic solvent was removed by steam distillati~n. The remaining aqueous slurry filtered rapidly, yielding 958 lb. of wet solids.
, .
1 The solids were stirred into a solution containing two parts acetone to one part water, and sufficient sodium hydroxide to provide about 10~ in excess over that needed - to dissolve the 4-(fluoranthyl)-4-oxobutanoic acid prod~ct.
Insoluble tars were removed by filtration, and dilute hydrochloric acid was used to re-precipitate the acid prod~ct~ After filtration, the solids were subjected to an additional dissolution in base and precipitation with acid, as described above, resulting in a purified material.
A 109 lb. portion of the purified material was placed in the 1000 gallon jacketed reactor with about 45 gallons of diethylene glycol. The mixture was stirred and 46 lb.
of potassium hydroxide and 43 lb. of hydrazine hydrate were added. Steam was passed through the jacket to obtain a temperature of about 120C, and then the temperature was increased to 155C. A nitrogen purge was used to maintain an oxygen content less than about 1% and a distillation receiver was used to collect the water and excess hydrazine which distilled from the reactor.
After cooling to about 25C, the mixture was diluted with 110 gallons of water and acidified with 12 gallons of lON hydrochloric acid in about 50 gallons of water.
The solid 4-(fluoranthyl)-butanoic acid which formed was collected on a filter.
A sample of this product was tested in a pilot plant, as in Example III, using a different limestone ore feed material, and yielding the following results for a total of 406 lb. of feed:
.
o r~
o ~V o ~ ~ _ ~ o O ~ O~ CO ~ 0 O~ ~D
~ V
p~ dP
_ QJ ~ O O O O ~ ~
~ O ~ CO er ~D O a~
t U~ N 1` ~ 1-- 1~ 1`
.~
r~
O
O
~0 dP
~ c O
C ~ o cn O ~ ~ D
U~ O . . . . . .
o LO ~r a ~ ~D ~ U') Lr) V
_ _ _ t) CU
O o o U V
o v ~ ~ a u~
w o ~ 3 ~ 3 ~ ~
_ .
c ~
~; O ~ ~ ~r . _ .
3~
1 Example VII
Because of the rather low product yield obtained in the previous large-scale production run (Example VI), a further production of 4-(fluoranthyl)-butanoic acid was ~ndertaken using a different solvent system. A 1500 gallon jacketed reac$or was charged with 660 gal. of chlorobenzene, 550 lb. of fluoranthene and 275 lb. of succinic anhydride. To this was added ~05 lb. of aluminum chloride. The temperature was raised to about 60C and maintained at 55_5C or about 12 hours~
The reaction mixture was quenched by the slow addi-tion of 200 gal. of lON hydrochloric acid in 500 gal.
of cold water, and circulating cold water through the reactor jacket during the addition. By adjusting the addition rate, the reactor temperature was kept below about 80C.
Steam distillation was ued to remove the solvent.
After cooling the mixture to about 35C, the solid inter-mediate product was isolated by filtration, then transfer red to a 1000 gallon reactor.
To this product was added 312 gal. of diethylene glycol, 320 lb. of 91% potassium hydroxide, 308 lb. of 85~ hydrazine hydrate and 37.5 gal. of water. A nitrogen purge reduced the oxygen content of the reactor to less than 1%, and the mixture was heated to about 155~C. Excess hydrazine and water distilled from the reactor during the heating. The reaction mixture was maintained at about 155~C for eight hours, cooled to about 50C and diluted with about 750 gal. of water~
8~6 ~ 33 -1 A 100 gal. portion of lON hydrochloric acid was added and, after stirring for an hour, the mixture was filtered and washed with water, yielding 1623 lb. of wet cake.
A sample of this product was tested in a pilot plant, as in Example III, using a different limestone ore feed material, and yielding the following results for a total of 1808 lb. of feed:
~.
~69~3~l6 - _ --34 ~r O ~ 1~-- ~ r r ~
1~ ~~ r~ ~ r~ ~ r~ I~ r~ U~ r~ ~D O
~ ~o~ ~D~ r~~ ~_ a7 u~ ~~ ~D CD U~
iJ
o~
____ _= _ ~ ~D ~r CD ~ ~-- r~ r~ ~D ~er r- r~ ~ o O .. .- .- .. .. .- .-.~ ~ ~ r-r~ ~ ~ r~ oo u~ ~ ~_ cl~ ~ a~- ~1_ ~t~
_ cJ
C O
._~ Y
_l ~ r- u~ Ln a~ ~ L~ In ~ D ~ r- ~ er ~ i ~ ~ cr ,1 ~ u~ .- ~ O r~ ~D
O O ~ r- ~ cr~ r~ u~ CD--~ r~ --m O
_ ~
~ O. ~ ~ ~ u~ u~ ~ t~ O U~ U~ O O
D t.~ ~ r~ O r~ N ~ ~- ~
v sv~ ~~ ~ cr ~ m--~ ~ r u~ .
Ocr .-.r~ r-.- tn ~ ~D u l ~ r~ r~ ~ a:~
r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
_r~ r~~P ~u~ er ~ u~ ~ ~D ~ r~ O~ O
~ r ~ ~r ~ ~ r ~ ~ ~D ~ t~ ~
~ =
~ o ~
E ~ V tJ t~ V ~ t~
J ~ c C ~ e C C C
O O ~ C ~ ~ O
~J V t,) ~ ~ ~ ~.) t,~
v ~ n~ ~ ~ ~ ~ aJ
o u~ ~) ~ a~ J~ a~ v ~ J ~u ~ ~J JJ ~ V
~J E 0E~ u~ E u~ E u~ E~ u~ E U:l E
r~ .~ r~.~t ~U .~ I~~ 1~ ~ a r~
O ~ 3r_i 3 r~ r. l 3:r ~ ~a 3 ~ 3 _ _ _ __ . ~ ~D ~ _ ~ ~ r 0 u~ u~ ~ ~ ~ ~D
~z ~ ~ ~ .
___ .
- ~16~8~6 1 Example VIII
A fluorescent compound containing a cationic surfactant . group, 7-diethylamino-4-me~hylcoumarin, acid sulfate was prepared by dissolving the commercially available amine in sulfuric acid and diluting to a 0.24% by weight solution.
This solution was evaluated for its ability to selectively coat minerals by the immersion of a clean mineral specimen in the solution for about 15 seconds, followed by rinsing of the specimen under running water and visual examination of the specimen under an ultraviolet light. The results were as follows:
Mineral Fluorescen~ intensity Quartzite, SiO2 medium Albite, NaAlSi3O8 medium Wollastonite, CaSiO3 strong 20 Quartz, SiO2 medium Calcite, CaCO3 ~trong Pyrite, ~from coal), FeS2 strong Oil Shale (C10 gal/ton) medium Oil Shale (>25 gal/ton) none 25 Coal none Chert, SiO2 none Slate none The results show that the following economically significant separations can be made using this compound as a surface-selective agent with a technique as in Example III:
1 1. Coal can be separated from inorganic materials such as pyrite, calcite, dolomite or limestone; and coal of high BTU
content can be separated from lower BTU content material.
2. Higher grade oil shale can be separated from lower grade oil shale and from calcite, dolomite or limestone.
3. Wollastonite can be separated from other silicates, such as albite and quartz.
1~
1 Example VII
Because of the rather low product yield obtained in the previous large-scale production run (Example VI), a further production of 4-(fluoranthyl)-butanoic acid was ~ndertaken using a different solvent system. A 1500 gallon jacketed reac$or was charged with 660 gal. of chlorobenzene, 550 lb. of fluoranthene and 275 lb. of succinic anhydride. To this was added ~05 lb. of aluminum chloride. The temperature was raised to about 60C and maintained at 55_5C or about 12 hours~
The reaction mixture was quenched by the slow addi-tion of 200 gal. of lON hydrochloric acid in 500 gal.
of cold water, and circulating cold water through the reactor jacket during the addition. By adjusting the addition rate, the reactor temperature was kept below about 80C.
Steam distillation was ued to remove the solvent.
After cooling the mixture to about 35C, the solid inter-mediate product was isolated by filtration, then transfer red to a 1000 gallon reactor.
To this product was added 312 gal. of diethylene glycol, 320 lb. of 91% potassium hydroxide, 308 lb. of 85~ hydrazine hydrate and 37.5 gal. of water. A nitrogen purge reduced the oxygen content of the reactor to less than 1%, and the mixture was heated to about 155~C. Excess hydrazine and water distilled from the reactor during the heating. The reaction mixture was maintained at about 155~C for eight hours, cooled to about 50C and diluted with about 750 gal. of water~
8~6 ~ 33 -1 A 100 gal. portion of lON hydrochloric acid was added and, after stirring for an hour, the mixture was filtered and washed with water, yielding 1623 lb. of wet cake.
A sample of this product was tested in a pilot plant, as in Example III, using a different limestone ore feed material, and yielding the following results for a total of 1808 lb. of feed:
~.
~69~3~l6 - _ --34 ~r O ~ 1~-- ~ r r ~
1~ ~~ r~ ~ r~ ~ r~ I~ r~ U~ r~ ~D O
~ ~o~ ~D~ r~~ ~_ a7 u~ ~~ ~D CD U~
iJ
o~
____ _= _ ~ ~D ~r CD ~ ~-- r~ r~ ~D ~er r- r~ ~ o O .. .- .- .. .. .- .-.~ ~ ~ r-r~ ~ ~ r~ oo u~ ~ ~_ cl~ ~ a~- ~1_ ~t~
_ cJ
C O
._~ Y
_l ~ r- u~ Ln a~ ~ L~ In ~ D ~ r- ~ er ~ i ~ ~ cr ,1 ~ u~ .- ~ O r~ ~D
O O ~ r- ~ cr~ r~ u~ CD--~ r~ --m O
_ ~
~ O. ~ ~ ~ u~ u~ ~ t~ O U~ U~ O O
D t.~ ~ r~ O r~ N ~ ~- ~
v sv~ ~~ ~ cr ~ m--~ ~ r u~ .
Ocr .-.r~ r-.- tn ~ ~D u l ~ r~ r~ ~ a:~
r ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~
_r~ r~~P ~u~ er ~ u~ ~ ~D ~ r~ O~ O
~ r ~ ~r ~ ~ r ~ ~ ~D ~ t~ ~
~ =
~ o ~
E ~ V tJ t~ V ~ t~
J ~ c C ~ e C C C
O O ~ C ~ ~ O
~J V t,) ~ ~ ~ ~.) t,~
v ~ n~ ~ ~ ~ ~ aJ
o u~ ~) ~ a~ J~ a~ v ~ J ~u ~ ~J JJ ~ V
~J E 0E~ u~ E u~ E u~ E~ u~ E U:l E
r~ .~ r~.~t ~U .~ I~~ 1~ ~ a r~
O ~ 3r_i 3 r~ r. l 3:r ~ ~a 3 ~ 3 _ _ _ __ . ~ ~D ~ _ ~ ~ r 0 u~ u~ ~ ~ ~ ~D
~z ~ ~ ~ .
___ .
- ~16~8~6 1 Example VIII
A fluorescent compound containing a cationic surfactant . group, 7-diethylamino-4-me~hylcoumarin, acid sulfate was prepared by dissolving the commercially available amine in sulfuric acid and diluting to a 0.24% by weight solution.
This solution was evaluated for its ability to selectively coat minerals by the immersion of a clean mineral specimen in the solution for about 15 seconds, followed by rinsing of the specimen under running water and visual examination of the specimen under an ultraviolet light. The results were as follows:
Mineral Fluorescen~ intensity Quartzite, SiO2 medium Albite, NaAlSi3O8 medium Wollastonite, CaSiO3 strong 20 Quartz, SiO2 medium Calcite, CaCO3 ~trong Pyrite, ~from coal), FeS2 strong Oil Shale (C10 gal/ton) medium Oil Shale (>25 gal/ton) none 25 Coal none Chert, SiO2 none Slate none The results show that the following economically significant separations can be made using this compound as a surface-selective agent with a technique as in Example III:
1 1. Coal can be separated from inorganic materials such as pyrite, calcite, dolomite or limestone; and coal of high BTU
content can be separated from lower BTU content material.
2. Higher grade oil shale can be separated from lower grade oil shale and from calcite, dolomite or limestone.
3. Wollastonite can be separated from other silicates, such as albite and quartz.
1~
4. Quartz can be separated from calcite, dolomite or limestone.
5. Calcite, dolomite, or limestone can be separated from fluorospar, or from phosphate minerals such as phospha~e rock.
Example IX
To more quantitatiwely test the separation technique for oil shale, the following experiment was conducted:
a solution of 4.0 g of 7-diethylamino-4-methylcoumarin, acid sulfate was made in 2 liters of deioni~ed watert giving a pH of about 1.5. Oil shale particles having a size in the range of about one to about two inches were immersed in the clear yellow solution, rinsed with deionized water and visually examined under an ultraviolet light~
The more fl~orescent particles were separated from the less fluorescent particles, and the two fractions were crushed for oil analysis by the ~ischer assay.
Barrel 27 is a high grade oil shale with an oil analysis which averages about 25 ~al/ton. Barrel 187 is a low grade material which analyzes in the range of 8 to 11 gal/ton.
8~
1 The following results obtained from the experiment, showing the fraction weights, number of particles in the fraction, and oil content of each fraction:
Higher Fluorescence Weak Fluorescence Barrel Weight Particles gal/ton Weight Particles gal/ton 27 1073g 15 0.9 2589 5 46.1 187 8629 20 7.3 ~139 12 19.2 Another experiment was performed, using 644g (8 particles) from barrel 27 and 548g tlO particles) from barrel 187, which were mixed and treated as above. These were 12 particles (674g) with weak fluorescence, assaying 37.1 gal/ton, and 6 particles t519g) with higher fluore-scence which contained 8.8 gal/ton of oil.
Each of these experiments shows that a substantial upgrading can be obtained by selectively labeling oil shale particles.
Ex~ le X
A cationic derivative of 4-(fluoranthyl)-butanoic acid was prepared by reaction with diethylenetriamine, using diethylene glycol as a solvent, according to the following reaction:
2 F -- ~CH2 )3 COOH + (H2NCH2CH2 ) 2 NH ~ ~F -- (CR2 ) 3~NH (CH2 ) 2~ NH
That portion of the reaction product which was in-soluble in dilute sodium hydroxide was extracted with dilute acetic acid, and the resulting solution evaluated for coating minerals.
~1698~6 1 Mineral specimens were immersed in the solution for 20 to 30 seconds, rinsed with deionized water and visually examined under ultraviolet light, yielding the following - res~lts:
M _ ral Fluorescent intensity_ Chert, SiO2 moderate Microcline~ K~lsi38 moderate 10 Wollastonite, CaSiO3 strong Limestone, Ca,Mg,CO3 weak These results show utility of the compound as a surface-selective agent for sorting mixtures of silicate minerals. This type of surface-selective compound can be viewed as effective over the entire aqueous pH range, an important property due to the influence of pH on the adherence of collectors to ore surfaces, a phenomenon which has been observed in ~he ore flotation art. With cationic fluorescent compounds, a structure can be chosen for its usefulness in a given pH range, e.g. amine salts containing the -N~+ group will be useful in the pH range dictated by the basicity of the amine, while quarternary amine salts will be useful over the entire pH range.
Example XI
In a manner similar to that of Example IX, the com-pound F - (CH2)3 CONH~CH2~ NH2 was prepared by the reaction of 4-(fluoranthyl)-butanoic acid and ethylene diamine in a diethylene glycol solvent, and precipitated by dilute sodium hydroxide. The product was extracted with a toluene-isopropanol mixture, and the extract was concen-trated by distillation and, finally/ evaporated of the ~ 6~6 1 solvents. After dispersal in water, the product was fil-tered and dried over phosphorus pentoxide, then dissolved in dilute acetic acid for coating experiments.
A speciman of microcline was coated by immersion in the acetic acid solution, but its visual fluorescence appeared to be too weak for a practical separation process.
An activation step was conducted on a second specimen by immersion in a 0.4% solution of hydrofluoric acid for about 10 seconds, followed by a deionized water rinse.
After activation, the fluorescent surface-active agent coating yielded a more intense flourescence, indicating that the activating step could be used to advantage.
Several mineral specimen were immersed in the acetic acid solution (at about pH 5) for 10 to 15 seconds, rinsed with deionized water, and visually examined under ultra-violet light, giving the following results:
MineralFluorescent intens~y Quartzite, SiO2 moderate Albite, NaALsi38 moderate Wollastonite, CaSiO3 strong Gneiss m~derate Diopside, CaM9(si3)2 weak Chert, SiO2 weak A separate test was conducted by simultaneously immersing samples of quartzite and limestone in the acetic acid solution (at about pH 3). The samples were removed, rinsed and evaluated under ultraviolet light. Selectivity of the coating was shown by the somewhat ~ore intense fluorescence of quartzite relative to limestone.
` :
1~ 16 -- ~o --1 Example XII
_ _ _ _ _ . _ _ There are low grade refractory silver ores in which - the dilute silver values are associated with a much larger amount of iron and/or manganese minerals in a siliceous (e.g., quartz, serpentine) matrix (e.g. a limonitic ore).
An example of such an ore can be found in the Candelaria Mining District of Nevada. A sample, consisting of both limonitic and non-limonitic 2-3" ore particles having cross-sections of about 2 to 3 inches, was treated with 0.1% (wt.) FBA, sodium salt, rinsed and examined for fluorescence intensity. The limonitic ore was more fluore~
scent than the non-limonitic ore. This indicates that concentration of the silver could be achieved even though the difference in fluDrescence was small. Use of a more intense fluorescent moiety in the fluorescent surfactant and/or a more active surfactant moiety would increase the difference in the fluorescence. For example, a diamino-stilbene cyanuric chloride derived or a distyrylbiphenyl derived fluorescent moiety would be more fluorescent than the fluoranthene derived moiety. The example also indicates that anionic fluorescent surfacts can be useful in sorting limonitic ores.
Exarnple XIII
A Mexican silver (5.5 oz/ton) ore containing silver associated with galena and sphalerite in a siliceous matrix contaminated by limestone was concentrated by conditioning and ejecting ~with water jets in freefall) the selectively marked limestone. In this separation a 1~ dispersion in water of a 0.5% 7-diethylamino-4-methylcoumarin ~i.e. DMC) in tall oil was sprayed on 2~4 lb of ore and the ore -1 sorted. The results are sho~n below.
~'aste 1.2 oz/ton 9~5~ silver 43.4% wt.
- Concentrate 8.8 oz/ton 90.5% silver 56.6% wt.
These results demonstrate the concentration of more than 90% of the silver in 56~ of the ore. It is also possible to label and eject the siliceous minerals (e.g.
quartz) as in a second conditioning and separation procedure, thereby further concentrating the silver values (or, the siliceous separation could be made instead of separating the limestone). In general siliceous materials can be selec-tively marked with compounds containing an amino-group.
Although, in this example, the tall oil is probably the major influence on the surface selectivity, if the DMC
is dissolved in dilute, aqueous mineral acid to produce an acidic solution (e.g. below about pH 5, typically about p~
2 to about pH 3), the DMC can ~unction as both the surface selective agent and the detectable moiety (e.g. by induced fluorescence). Alternatively a water soluble salt of fluorescent unsaturated carboxylic acid, such as the Na or X salt of FBA, can be used in a~ueous solution in the concentration of silver ores which contain limestone as a diluent or impurity.
Although the above Examples XII and XIII are of silver ores where the silver mineral is associated with a gross mineral such as the limonitic quartz ore of Example XII or the quart2 of Example XIII and/or where there is also present a third mineral which can be considered a contami-nant such as the quartz in Example XII and the limestone in Example XIII and many other desirable minerals, such as those of gold, tungsten, uranium, boron, chromium, nickel, lead, 7inc, and antimony, can be concentrated in these examples and the other description in this application~
.
~L69~3~6 _ ~2 -1 These results demonstrate the concentration of more than 90% of the silver in 56% of the ore. It is also possible to label and eject the siliceo~s minerals (e.g.
- quartz) as in a second conditioning and separation pro~
S cedure, thereby further concentrating the silver values (or, the siliceous separation could be made instead of separating the limestone). In general siliceous materials can be selectively marked with compounds containing an amino-group.
Although, in this example, the tall oil is probably the major influence on the surface sélectivity, if the DMC
is dissolved in dilute, aqueous mineral acid to produce an acidic solution (e.g. below about pH 5, typically abou~ pH
2 to about pH 3), the DMC can function as both the surface selective agent and the detectable moiety ~e.g. by induced fluorescence). Alternatively a water soluble salt of fluorescent unsaturated carboxylic acid, such as the Na or K salt of FBA, can be used in aqueous solution in the concentration of silver ores which contain limestone as a diluent or impurity.
Although the above Examples XII and XIII are of silver ores where the silver mineral is associated with a gross mineral such as the limonitic quartz ore of Example XII or the quartz of Example XIII and/or where there is also present a third mineral which can he considered a contami nant such as the quartz in Example XII and the limestone in Example XIII and many other desirable minerals, such as ~0 those of gold, tungsten, uranium, boron, ~hromium, nickel, lead, zinc, an~ antimony, can be concentrated in these examples and the other description in this application.
~16~ 6 1 Of course, in an ore where the desirable mineral is concentrated in a limestone fraction, a limestone marking agent can be used to aid in concentrating the desired - mineral value by separating the limestone from other minerals in the ore.
Example XIV
A synthetic sample of maynesite, calcite and siliceous rock was formulated containing 26.8% magnesite, 30.4~ cal-cite and 42.8% siliceous rock in particles of about 1 inch to about 3 inch screen size. After washing, the material was conditioned with a 0.1% solution of 8-hydroxyquinoline in water, as the sodium salt. After conditioning, the material was rinsed and passed through an irradiation device to induce fluorescence.
Hand sorting of the conditioned, fluorescing particles produced the fractions shown below:
FRACTION % Separation % Magnesite ~ Dist.
Eject 25.1 88.0 82.3 Reject 74.9 12.0 17;7 Head 100.0 26.8 100.0 By "eject" is meant that in a Mathews-type separator, the particle would be deflected (or ejected) from its free-fall path.
Visible fluorescence is a desirable property for the rapid evaluation of a surface-selective agent, and is also convenient for plant operators to use in empirical quality control checks of a separation process. However, an agent having no visible-region fluorescenoe or only a 1~6~8~6 4~ --1 weak visible fluorescence can be quite useful in those processes which detect fluorescence by means of an electro-optical instrument, since the wavelength to which such - an instrument responds can be altered as required.
Example IX
To more quantitatiwely test the separation technique for oil shale, the following experiment was conducted:
a solution of 4.0 g of 7-diethylamino-4-methylcoumarin, acid sulfate was made in 2 liters of deioni~ed watert giving a pH of about 1.5. Oil shale particles having a size in the range of about one to about two inches were immersed in the clear yellow solution, rinsed with deionized water and visually examined under an ultraviolet light~
The more fl~orescent particles were separated from the less fluorescent particles, and the two fractions were crushed for oil analysis by the ~ischer assay.
Barrel 27 is a high grade oil shale with an oil analysis which averages about 25 ~al/ton. Barrel 187 is a low grade material which analyzes in the range of 8 to 11 gal/ton.
8~
1 The following results obtained from the experiment, showing the fraction weights, number of particles in the fraction, and oil content of each fraction:
Higher Fluorescence Weak Fluorescence Barrel Weight Particles gal/ton Weight Particles gal/ton 27 1073g 15 0.9 2589 5 46.1 187 8629 20 7.3 ~139 12 19.2 Another experiment was performed, using 644g (8 particles) from barrel 27 and 548g tlO particles) from barrel 187, which were mixed and treated as above. These were 12 particles (674g) with weak fluorescence, assaying 37.1 gal/ton, and 6 particles t519g) with higher fluore-scence which contained 8.8 gal/ton of oil.
Each of these experiments shows that a substantial upgrading can be obtained by selectively labeling oil shale particles.
Ex~ le X
A cationic derivative of 4-(fluoranthyl)-butanoic acid was prepared by reaction with diethylenetriamine, using diethylene glycol as a solvent, according to the following reaction:
2 F -- ~CH2 )3 COOH + (H2NCH2CH2 ) 2 NH ~ ~F -- (CR2 ) 3~NH (CH2 ) 2~ NH
That portion of the reaction product which was in-soluble in dilute sodium hydroxide was extracted with dilute acetic acid, and the resulting solution evaluated for coating minerals.
~1698~6 1 Mineral specimens were immersed in the solution for 20 to 30 seconds, rinsed with deionized water and visually examined under ultraviolet light, yielding the following - res~lts:
M _ ral Fluorescent intensity_ Chert, SiO2 moderate Microcline~ K~lsi38 moderate 10 Wollastonite, CaSiO3 strong Limestone, Ca,Mg,CO3 weak These results show utility of the compound as a surface-selective agent for sorting mixtures of silicate minerals. This type of surface-selective compound can be viewed as effective over the entire aqueous pH range, an important property due to the influence of pH on the adherence of collectors to ore surfaces, a phenomenon which has been observed in ~he ore flotation art. With cationic fluorescent compounds, a structure can be chosen for its usefulness in a given pH range, e.g. amine salts containing the -N~+ group will be useful in the pH range dictated by the basicity of the amine, while quarternary amine salts will be useful over the entire pH range.
Example XI
In a manner similar to that of Example IX, the com-pound F - (CH2)3 CONH~CH2~ NH2 was prepared by the reaction of 4-(fluoranthyl)-butanoic acid and ethylene diamine in a diethylene glycol solvent, and precipitated by dilute sodium hydroxide. The product was extracted with a toluene-isopropanol mixture, and the extract was concen-trated by distillation and, finally/ evaporated of the ~ 6~6 1 solvents. After dispersal in water, the product was fil-tered and dried over phosphorus pentoxide, then dissolved in dilute acetic acid for coating experiments.
A speciman of microcline was coated by immersion in the acetic acid solution, but its visual fluorescence appeared to be too weak for a practical separation process.
An activation step was conducted on a second specimen by immersion in a 0.4% solution of hydrofluoric acid for about 10 seconds, followed by a deionized water rinse.
After activation, the fluorescent surface-active agent coating yielded a more intense flourescence, indicating that the activating step could be used to advantage.
Several mineral specimen were immersed in the acetic acid solution (at about pH 5) for 10 to 15 seconds, rinsed with deionized water, and visually examined under ultra-violet light, giving the following results:
MineralFluorescent intens~y Quartzite, SiO2 moderate Albite, NaALsi38 moderate Wollastonite, CaSiO3 strong Gneiss m~derate Diopside, CaM9(si3)2 weak Chert, SiO2 weak A separate test was conducted by simultaneously immersing samples of quartzite and limestone in the acetic acid solution (at about pH 3). The samples were removed, rinsed and evaluated under ultraviolet light. Selectivity of the coating was shown by the somewhat ~ore intense fluorescence of quartzite relative to limestone.
` :
1~ 16 -- ~o --1 Example XII
_ _ _ _ _ . _ _ There are low grade refractory silver ores in which - the dilute silver values are associated with a much larger amount of iron and/or manganese minerals in a siliceous (e.g., quartz, serpentine) matrix (e.g. a limonitic ore).
An example of such an ore can be found in the Candelaria Mining District of Nevada. A sample, consisting of both limonitic and non-limonitic 2-3" ore particles having cross-sections of about 2 to 3 inches, was treated with 0.1% (wt.) FBA, sodium salt, rinsed and examined for fluorescence intensity. The limonitic ore was more fluore~
scent than the non-limonitic ore. This indicates that concentration of the silver could be achieved even though the difference in fluDrescence was small. Use of a more intense fluorescent moiety in the fluorescent surfactant and/or a more active surfactant moiety would increase the difference in the fluorescence. For example, a diamino-stilbene cyanuric chloride derived or a distyrylbiphenyl derived fluorescent moiety would be more fluorescent than the fluoranthene derived moiety. The example also indicates that anionic fluorescent surfacts can be useful in sorting limonitic ores.
Exarnple XIII
A Mexican silver (5.5 oz/ton) ore containing silver associated with galena and sphalerite in a siliceous matrix contaminated by limestone was concentrated by conditioning and ejecting ~with water jets in freefall) the selectively marked limestone. In this separation a 1~ dispersion in water of a 0.5% 7-diethylamino-4-methylcoumarin ~i.e. DMC) in tall oil was sprayed on 2~4 lb of ore and the ore -1 sorted. The results are sho~n below.
~'aste 1.2 oz/ton 9~5~ silver 43.4% wt.
- Concentrate 8.8 oz/ton 90.5% silver 56.6% wt.
These results demonstrate the concentration of more than 90% of the silver in 56~ of the ore. It is also possible to label and eject the siliceous minerals (e.g.
quartz) as in a second conditioning and separation procedure, thereby further concentrating the silver values (or, the siliceous separation could be made instead of separating the limestone). In general siliceous materials can be selec-tively marked with compounds containing an amino-group.
Although, in this example, the tall oil is probably the major influence on the surface selectivity, if the DMC
is dissolved in dilute, aqueous mineral acid to produce an acidic solution (e.g. below about pH 5, typically about p~
2 to about pH 3), the DMC can ~unction as both the surface selective agent and the detectable moiety (e.g. by induced fluorescence). Alternatively a water soluble salt of fluorescent unsaturated carboxylic acid, such as the Na or X salt of FBA, can be used in a~ueous solution in the concentration of silver ores which contain limestone as a diluent or impurity.
Although the above Examples XII and XIII are of silver ores where the silver mineral is associated with a gross mineral such as the limonitic quartz ore of Example XII or the quart2 of Example XIII and/or where there is also present a third mineral which can be considered a contami-nant such as the quartz in Example XII and the limestone in Example XIII and many other desirable minerals, such as those of gold, tungsten, uranium, boron, chromium, nickel, lead, 7inc, and antimony, can be concentrated in these examples and the other description in this application~
.
~L69~3~6 _ ~2 -1 These results demonstrate the concentration of more than 90% of the silver in 56% of the ore. It is also possible to label and eject the siliceo~s minerals (e.g.
- quartz) as in a second conditioning and separation pro~
S cedure, thereby further concentrating the silver values (or, the siliceous separation could be made instead of separating the limestone). In general siliceous materials can be selectively marked with compounds containing an amino-group.
Although, in this example, the tall oil is probably the major influence on the surface sélectivity, if the DMC
is dissolved in dilute, aqueous mineral acid to produce an acidic solution (e.g. below about pH 5, typically abou~ pH
2 to about pH 3), the DMC can function as both the surface selective agent and the detectable moiety ~e.g. by induced fluorescence). Alternatively a water soluble salt of fluorescent unsaturated carboxylic acid, such as the Na or K salt of FBA, can be used in aqueous solution in the concentration of silver ores which contain limestone as a diluent or impurity.
Although the above Examples XII and XIII are of silver ores where the silver mineral is associated with a gross mineral such as the limonitic quartz ore of Example XII or the quartz of Example XIII and/or where there is also present a third mineral which can he considered a contami nant such as the quartz in Example XII and the limestone in Example XIII and many other desirable minerals, such as ~0 those of gold, tungsten, uranium, boron, ~hromium, nickel, lead, zinc, an~ antimony, can be concentrated in these examples and the other description in this application.
~16~ 6 1 Of course, in an ore where the desirable mineral is concentrated in a limestone fraction, a limestone marking agent can be used to aid in concentrating the desired - mineral value by separating the limestone from other minerals in the ore.
Example XIV
A synthetic sample of maynesite, calcite and siliceous rock was formulated containing 26.8% magnesite, 30.4~ cal-cite and 42.8% siliceous rock in particles of about 1 inch to about 3 inch screen size. After washing, the material was conditioned with a 0.1% solution of 8-hydroxyquinoline in water, as the sodium salt. After conditioning, the material was rinsed and passed through an irradiation device to induce fluorescence.
Hand sorting of the conditioned, fluorescing particles produced the fractions shown below:
FRACTION % Separation % Magnesite ~ Dist.
Eject 25.1 88.0 82.3 Reject 74.9 12.0 17;7 Head 100.0 26.8 100.0 By "eject" is meant that in a Mathews-type separator, the particle would be deflected (or ejected) from its free-fall path.
Visible fluorescence is a desirable property for the rapid evaluation of a surface-selective agent, and is also convenient for plant operators to use in empirical quality control checks of a separation process. However, an agent having no visible-region fluorescenoe or only a 1~6~8~6 4~ --1 weak visible fluorescence can be quite useful in those processes which detect fluorescence by means of an electro-optical instrument, since the wavelength to which such - an instrument responds can be altered as required.
Claims (55)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for separating ore particles from gangue particles, com-prising the steps of:
a. conditioning the particles with a conditioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively coat either i. at least a portion of the ore particles or ii. at least a portion of the gangue particles to the substantial exclusion of the other;
b. detecting the coated particles; and c. separating the detected, coated particles from the substantially uncoated particles.
a. conditioning the particles with a conditioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively coat either i. at least a portion of the ore particles or ii. at least a portion of the gangue particles to the substantial exclusion of the other;
b. detecting the coated particles; and c. separating the detected, coated particles from the substantially uncoated particles.
2. A process for separating ore particles, which include relatively higher grade ore particles and relatively lower grade ore particles, from gangue particles comprising the steps of:
a. conditioning the particles with a conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety, which renders the compound fluorescent when exposed to external radia-tion, to selectively coat either i. at least a portion of the ore particles or ii. at least a portion of the gangue particles to the substantial exclusion of the other;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguishing the coated particles from the substantially uncoated particles; and c. separating the fluorescing, coating particles from the substan-tially uncoated particles.
a. conditioning the particles with a conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety, which renders the compound fluorescent when exposed to external radia-tion, to selectively coat either i. at least a portion of the ore particles or ii. at least a portion of the gangue particles to the substantial exclusion of the other;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguishing the coated particles from the substantially uncoated particles; and c. separating the fluorescing, coating particles from the substan-tially uncoated particles.
3. A process as in claim 2, in which coated higher grade ore particles are distinguished and separated from lesser coated lower grade ore particles and the substantially uncoated gangue particles.
4. A process as in claim 2, in which the coated gangue particles and lesser coated lower grade ore particles are distinguished and separated from substantially uncoated higher grade ore particles.
5. A process as in claim 2, in which the surface-selective group com-prises a cationic surfactant.
6. A process as in claim 2, in which the surface-selective group com-prises an anionic surfactant.
7. A process as in claim 2, in which the surface-selective group com-prises a nonionic surfactant.
8. A process as in claim 2, in which the surface-active group comprises an amphoteric surfactant.
9. A process as in claim 2, in which the fluorescent moiety comprises a polynuclear aromatic group.
10. A process as in claim 2, wherein the particles have a size in the range of from about one-fourth inch to about eight inches.
11. A process as in claim 2, wherein the particles have a size in the range of from about one-half to about four inches.
12. A process as in claim 2, wherein the conditioning agent is soluble in water.
13. A process as in claim 12, wherein the conditioning comprises immer-sion of the particles in an aqueous solution of the conditioning agent.
14. A process as in claim 12, wherein the conditioning comprises spray-ing the particles with an aqueous solution of the conditioning agent.
15. A process for separating higher grade ore particles from lower grade ore particles and gangue particles, comprising the steps of:
a. conditioning the particles by spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation thereby selectively marking the ore particles in a degree dependent upon the surface concentration of said component, or in a degree dependent upon the grade of the ore, to the substantial exclusion of the gangue particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent for distinguishing among marked particles and marked particles from the substantially unmarked particles; and c. separating fluorescing, higher grade ore particles from the lesser fluorescing, lower grade ore particles and the substantially unmarked gangue particles.
a. conditioning the particles by spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation thereby selectively marking the ore particles in a degree dependent upon the surface concentration of said component, or in a degree dependent upon the grade of the ore, to the substantial exclusion of the gangue particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent for distinguishing among marked particles and marked particles from the substantially unmarked particles; and c. separating fluorescing, higher grade ore particles from the lesser fluorescing, lower grade ore particles and the substantially unmarked gangue particles.
16. A process for separating higher grade ore particles from lower grade ore particles and gangue particles, comprising the steps of:
a. conditioning the particles by spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, thereby selectively coating the gangue particles and, to a lesser degree, the lower grade ore particles, to the substantial exclusion of the higher grade ore particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent for distinguishing among the coated particles and coated particles from the substantially uncoated particles; and c. separating the fluorescing gangue particles and the lesser fluorescing, lower grade ore particles from the substantially uncoated higher grade ore particles.
a. conditioning the particles by spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, thereby selectively coating the gangue particles and, to a lesser degree, the lower grade ore particles, to the substantial exclusion of the higher grade ore particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent for distinguishing among the coated particles and coated particles from the substantially uncoated particles; and c. separating the fluorescing gangue particles and the lesser fluorescing, lower grade ore particles from the substantially uncoated higher grade ore particles.
17. A process for separating higher grade oil shale particles from lower grade oil shale particles, comprising the steps of:
a. conditioning the oil shale particles by spraying with an aqueous solution of a conditioning agent comprising 7-diethylamino-4-methylcoumarin acid sulfate having both a surface-selective functional group and a fluorescent moiety which renders the conditioning agent fluorescent when exposed to external radiation, thereby selectively coating the lower grade oil shale particles and coating to a lesser degree the higher grade oil shale particles;
b. irradiating the conditioned oil shale particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for dis-tinguishing among the coated oil shale particles; and c. separating the fluorescing lower grade oil shale particles from lesser fluorescing higher grade oil shale particles.
a. conditioning the oil shale particles by spraying with an aqueous solution of a conditioning agent comprising 7-diethylamino-4-methylcoumarin acid sulfate having both a surface-selective functional group and a fluorescent moiety which renders the conditioning agent fluorescent when exposed to external radiation, thereby selectively coating the lower grade oil shale particles and coating to a lesser degree the higher grade oil shale particles;
b. irradiating the conditioned oil shale particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for dis-tinguishing among the coated oil shale particles; and c. separating the fluorescing lower grade oil shale particles from lesser fluorescing higher grade oil shale particles.
18. A process for separating higher grade coal particles from lower grade coal particles and pyrite particles, comprising the steps of:
a. conditioning the coal particles by spraying with an aqueous solu-tion of a conditioning agent comprising 7-diethylamino-4-methylcoumarin acid sulfate having both a surface-selective functional group and a fluorescent moiety which renders the conditioning agent fluorescent when exposed to external radia-tion, thereby selectively coating the pyrite particles and, to a lesser degree, lower grade coal particles containing pyrites to the substantial exclusion of the higher grade coal particles;
b. irradiating the conditioned coal particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles; and c. separating the fluorescing pyrite particles and the lesser fluorescing, lower grade coal particles from the substantially uncoated higher grade coal particles.
a. conditioning the coal particles by spraying with an aqueous solu-tion of a conditioning agent comprising 7-diethylamino-4-methylcoumarin acid sulfate having both a surface-selective functional group and a fluorescent moiety which renders the conditioning agent fluorescent when exposed to external radia-tion, thereby selectively coating the pyrite particles and, to a lesser degree, lower grade coal particles containing pyrites to the substantial exclusion of the higher grade coal particles;
b. irradiating the conditioned coal particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles; and c. separating the fluorescing pyrite particles and the lesser fluorescing, lower grade coal particles from the substantially uncoated higher grade coal particles.
19. A process for separating higher grade calcite particles from lower grade calcite particles and siliceous gangue particles, comprising the steps of:
a. conditioning the particles by spraying with an aqueous solution of a conditioning agent comprising 7-diethylamino-4-methylcoumarin acid sulfate having both a surface-selective functional group and a fluorescent moiety which renders the conditioning agent fluorescent when exposed to external radiation thereby selectively coating the calcite particles in a degree dependent upon the grade of the calcite particle, to the substantial exclusion of the siliceous gangue particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles; and c. separating the 1uorescing, higher grade calcite particles from the lesser fluorescing, lower grade calcite particles and the substantially uncoated siliceous gangue particles.
a. conditioning the particles by spraying with an aqueous solution of a conditioning agent comprising 7-diethylamino-4-methylcoumarin acid sulfate having both a surface-selective functional group and a fluorescent moiety which renders the conditioning agent fluorescent when exposed to external radiation thereby selectively coating the calcite particles in a degree dependent upon the grade of the calcite particle, to the substantial exclusion of the siliceous gangue particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles; and c. separating the 1uorescing, higher grade calcite particles from the lesser fluorescing, lower grade calcite particles and the substantially uncoated siliceous gangue particles.
20. A process for separating higher grade wollastonite ore particles from lower grade wollastonite ore particles and siliceous gangue particles, com-prising the steps of:
a. conditioning the particles by spraying with an aqueous solution of a conditioning agent comprising 7-diethylamino-4-methylcoumarin acid sulfate having both a surface-selective functional group and a fluorescent moiety which renders the conditioning agent fluorescent when exposed to external radiation thereby selectively coating the wollastonite ore particles in a degree dependent upon the grade of the wollastonite ore, to the substantial exclusion of the siliceous gangue particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguishing the coated particles from the substantially uncoated particles; and c. separating the fluorescing, higher grade wollastonite ore particles from the lesser fluorescing, lower grade wollastonite ore particles and the substantially uncoated siliceous gangue particles.
a. conditioning the particles by spraying with an aqueous solution of a conditioning agent comprising 7-diethylamino-4-methylcoumarin acid sulfate having both a surface-selective functional group and a fluorescent moiety which renders the conditioning agent fluorescent when exposed to external radiation thereby selectively coating the wollastonite ore particles in a degree dependent upon the grade of the wollastonite ore, to the substantial exclusion of the siliceous gangue particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguishing the coated particles from the substantially uncoated particles; and c. separating the fluorescing, higher grade wollastonite ore particles from the lesser fluorescing, lower grade wollastonite ore particles and the substantially uncoated siliceous gangue particles.
21. A process for separating limestone ore particles, which include relatively higher grade ore particles and relatively lower grade ore limestone ore particles, from gangue particles comprising the steps of:
a. conditioning the particles with a conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety, which renders the compound fluorescent when exposed to external radia-tion, to selectively coat either i. at least a portion of the ore particles, or ii. at least a portion of the gangue particles leaving the other particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles, and c. separating the fluorescing, coated particles from the substan-tially uncoated particles.
a. conditioning the particles with a conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety, which renders the compound fluorescent when exposed to external radia-tion, to selectively coat either i. at least a portion of the ore particles, or ii. at least a portion of the gangue particles leaving the other particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles, and c. separating the fluorescing, coated particles from the substan-tially uncoated particles.
22. A process as in claim 21, in which the higher grade ore particles are coated, the lower grade ore particles are coated to a lesser degree than the higher grade ore particles, and the gangue remains substantially uncoated, and the coated higher grade ore particles are distinguished and separated from lower grade ore particles coated to a lesser degree and the substantially un-coated gangue particles.
23. A process as in claim 21, in which gangue particles are coated and lower grade ore particles are coated to a lesser degree than the gangue particles, and the higher grade ore particles remain substantially uncoated, and wherein the coated gangue particles and lower grade ore particles coated to a lesser degree than the gangue particles are distinguished and separated from substan-tially uncoated higher grade ore particles.
24. A process as in claim 23, in which the surface-selective group com-prises a cationic surfactant.
25. A process as in claim 22, in which the surface-selective group com-prises an anionic surfactant.
26. A process as in claim 21, in which the fluorescent moiety comprises a polynuclear aromatic group.
27. A process as in claim 21, wherein the ore and gangue particles have a size in the range of from about one-fourth inch to about eight inches.
28. A process as in claim 21, wherein the ore and gangue particles have a size in the range of from about one-half inch to about four inches.
29. A process as in claim 21, wherein the conditioning agent is soluble in water.
30. A process as in claim 29, wherein the conditioning comprises immers-ing the particles in an aqueous solution of the conditioning agent.
31. A process as in claim 29, wherein the conditioning comprises spraying the particles with an aqueous solution of the conditioning agent.
32. A process for separating higher grade limestone ore particles from lower grade limestone ore particles and gangue particles, comprising the steps of:
a. conditioning the limestone ore particles by spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, thereby selectively coating the ore particles in a degree dependent upon the grade of the ore, leaving the gangue particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles; and c. separating the fluorescing, coated higher grade ore particles from the lesser fluorescing, lower grade ore particles and the substantially uncoated gangue particles.
a. conditioning the limestone ore particles by spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, thereby selectively coating the ore particles in a degree dependent upon the grade of the ore, leaving the gangue particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles; and c. separating the fluorescing, coated higher grade ore particles from the lesser fluorescing, lower grade ore particles and the substantially uncoated gangue particles.
33. A process for separating higher grade limestone ore particles from lower grade limestone ore particles and gangue particles, comprising the steps of:
a. conditioning the limestone ore particles by spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, thereby selectively coating the gangue particles and, to a lesser degree, the lower grade ore particles, leaving the higher grade ore particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles; and c. separating the fluorescing coated gangue particles and the lesser fluorescing, lower grade ore particles from the substantially uncoated higher grade ore particles.
a. conditioning the limestone ore particles by spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, thereby selectively coating the gangue particles and, to a lesser degree, the lower grade ore particles, leaving the higher grade ore particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing the coated particles from the substantially uncoated particles; and c. separating the fluorescing coated gangue particles and the lesser fluorescing, lower grade ore particles from the substantially uncoated higher grade ore particles.
34. A process for separating high grade ore particles from limestone ore particles, which include high grade ore particles, low grade ore particles and gangue particles, which comprises the steps of:
a. conditioning the limestone ore particles with a conditioning agent comprising at least one compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, and selected from the group consisting of 4-(fluoranthyl)-butanoic acid and a salt of 7-diethylamino-4-methylcoumarin, to selectively coat high grade ore particles, and coat low grade ore particles to a lesser degree than the high grade ore particles, and wherein the gangue particles remain substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing coated high grade ore particles from low grade ore particles coated to a lesser degree and substantially uncoated gangue particles; and c. separating the fluorescing, coated high grade ore particles from the relatively low grade ore particles coated to a lesser degree and the sub-stantially uncoated gangue particles.
a. conditioning the limestone ore particles with a conditioning agent comprising at least one compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, and selected from the group consisting of 4-(fluoranthyl)-butanoic acid and a salt of 7-diethylamino-4-methylcoumarin, to selectively coat high grade ore particles, and coat low grade ore particles to a lesser degree than the high grade ore particles, and wherein the gangue particles remain substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing coated high grade ore particles from low grade ore particles coated to a lesser degree and substantially uncoated gangue particles; and c. separating the fluorescing, coated high grade ore particles from the relatively low grade ore particles coated to a lesser degree and the sub-stantially uncoated gangue particles.
35. A process for separating high grade ore particles from limestone ore particles, which include high grade ore particles and low grade ore particles and gangue particles, which comprises the steps of:
a. conditioning the limestone ore particles with a conditioning agent comprising the reaction product of 4-(fluoranthyl)-butanoic acid with a polyamine to provide a compound having a surface-selective functional group and a fluorescent moiety, to selectively coat the gangue particles and low grade ore particles and leave the relatively high grade ore particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient to distinguish coated gangue particles and low grade ore particles from substantially uncoated high grade ore particles; and c. separating the fluorescing, coated gangue particles and low grade ore particles from the substantially uncoated high grade ore particles.
a. conditioning the limestone ore particles with a conditioning agent comprising the reaction product of 4-(fluoranthyl)-butanoic acid with a polyamine to provide a compound having a surface-selective functional group and a fluorescent moiety, to selectively coat the gangue particles and low grade ore particles and leave the relatively high grade ore particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient to distinguish coated gangue particles and low grade ore particles from substantially uncoated high grade ore particles; and c. separating the fluorescing, coated gangue particles and low grade ore particles from the substantially uncoated high grade ore particles.
36. A process for separating high grade ore particles from limestone ore particles, which include high grade ore particles, low grade ore particles and gangue particles, which comprises the steps of:
a. conditioning the limestone ore particles of a size in the range of from about one-fourth inch to about eight inches with a conditioning agent comprising at least one compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, and selected from the group consisting of 4-(fluoranthyl)-butanoic acid and a salt of 7-diethylamino-4-methylcoumarin, to selectively coat high grade ore particles and coat low grade ore particles to a lesser degree than the high grade ore particles, and wherein the gangue particles remain substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing coated high grade ore particles from low grade ore particles coated to a lesser degree and substantially uncoated gangue particles; and c. separating the fluorescing, coated high grade ore particles from the relatively low grade ore particles coated to a lesser degree and the sub-stantially uncoated gangue particles.
a. conditioning the limestone ore particles of a size in the range of from about one-fourth inch to about eight inches with a conditioning agent comprising at least one compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, and selected from the group consisting of 4-(fluoranthyl)-butanoic acid and a salt of 7-diethylamino-4-methylcoumarin, to selectively coat high grade ore particles and coat low grade ore particles to a lesser degree than the high grade ore particles, and wherein the gangue particles remain substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree sufficient for distinguish-ing coated high grade ore particles from low grade ore particles coated to a lesser degree and substantially uncoated gangue particles; and c. separating the fluorescing, coated high grade ore particles from the relatively low grade ore particles coated to a lesser degree and the sub-stantially uncoated gangue particles.
37. A process for separating high grade ore particles from limestone ore particles, which include high grade ore particles, low grade ore particles and gangue particles, which comprises the steps of:
a. conditioning the limestone ore particles of a size in the range of from about one-fourth inch to about eight inches with a conditioning agent comprising the reaction product of 4-(fluoranthyl)-butanoic acid with a polyamine to provide a compound having a surface-selective functional group and a fluorescent moiety, to selectively coat the gangue particles and low grade ore particles and leave the relative-ly high grade ore particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree suffic-ient to distinguish coated gangue particles and low grade ore par-ticles from substantially uncoated high grade ore particles; and c. separating the fluorescing, coated gangue particles and low grade ore particles from the substantially uncoated high grade ore particles.
a. conditioning the limestone ore particles of a size in the range of from about one-fourth inch to about eight inches with a conditioning agent comprising the reaction product of 4-(fluoranthyl)-butanoic acid with a polyamine to provide a compound having a surface-selective functional group and a fluorescent moiety, to selectively coat the gangue particles and low grade ore particles and leave the relative-ly high grade ore particles substantially uncoated;
b. irradiating the conditioned particles to excite and induce fluorescence of the conditioning agent to a degree suffic-ient to distinguish coated gangue particles and low grade ore par-ticles from substantially uncoated high grade ore particles; and c. separating the fluorescing, coated gangue particles and low grade ore particles from the substantially uncoated high grade ore particles.
38. A process for separating a first type of particle from a mixture of the first type of particles and a second type of parti-cle, comprising the steps of:
a. conditioning the mixture of particles with a condit-ioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively mark either:
i. at least a portion of the first type of particle, to the substantial exclusion of the second type of particle, or ii. at least a portion of the second type of particle to the substantial exclusion of the first type of particle;
b. detecting the marked particles; and c. separating the detected, marked particles from the substantially unmarked particles in the mixture.
a. conditioning the mixture of particles with a condit-ioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively mark either:
i. at least a portion of the first type of particle, to the substantial exclusion of the second type of particle, or ii. at least a portion of the second type of particle to the substantial exclusion of the first type of particle;
b. detecting the marked particles; and c. separating the detected, marked particles from the substantially unmarked particles in the mixture.
39. A process as in claim 2, in which ore particles are coated in a degree dependent upon the grade of the ore, and coated higher grade ore particles are distinguished and separated from lesser coated lower grade ore particles and the substantially uncoated gangue particles.
40. A process as in claim 2, in which the ore particles are coated in a degree dependent upon the grade of the ore and in which the coated gangue particles and lesser coated lower grade ore particles are distinguished and separated from substantially uncoated higher grade ore particles.
41. A process as in claim 39, wherein the particles have a mesh or screen size in the range of from about one-fourth inch to about eight inches.
42. A process for separating higher grade ore particles from lower grade ore particles and gangue particles, comprising the steps of:
a. conditioning the particles by immersion in or spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when an ore component conditioned with said compound is exposed to external radiation thereby selectively marking the ore particles containing said ore component in a degree dependent upon the surface concentration of said component, or in a degree dependent upon the grade of the ore, to the substantial exclusion of the gangue particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the agent to a degree sufficient for distinguishing the marked particles from the substantially umarked particles; and c. separating the fluorescing, higher grade ore particles from the lesser fluorescing, lower grade ore particles and the substantially non-fluorescing gangue particles.
*
a. conditioning the particles by immersion in or spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when an ore component conditioned with said compound is exposed to external radiation thereby selectively marking the ore particles containing said ore component in a degree dependent upon the surface concentration of said component, or in a degree dependent upon the grade of the ore, to the substantial exclusion of the gangue particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the agent to a degree sufficient for distinguishing the marked particles from the substantially umarked particles; and c. separating the fluorescing, higher grade ore particles from the lesser fluorescing, lower grade ore particles and the substantially non-fluorescing gangue particles.
*
43. A process for separating higher grade ore particles from lower grade ore particles and gangue particles, comprising the steps of:
a. conditioning the particles by immersion in or spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, thereby selectively coating the gangue particles and, to a lesser degree, the lower grade ore particles, to the substantial exclusion of the higher grade ore particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the agent to a degree sufficient for distinguishing the coated particles from the substantially uncoated particles; and c. separating the fluorescing gangue particles and the lesser fluorescing, lower grade ore particles from the substantially uncoated higher grade ore particles.
a. conditioning the particles by immersion in or spraying with an aqueous solution of a conditioning agent, said conditioning agent comprising a compound having both a surface-selective functional group and a fluorescent moiety which renders the compound fluorescent when exposed to external radiation, thereby selectively coating the gangue particles and, to a lesser degree, the lower grade ore particles, to the substantial exclusion of the higher grade ore particles;
b. irradiating the conditioned particles to excite and induce fluorescence of the agent to a degree sufficient for distinguishing the coated particles from the substantially uncoated particles; and c. separating the fluorescing gangue particles and the lesser fluorescing, lower grade ore particles from the substantially uncoated higher grade ore particles.
44. A process as in claim 3 or 39, in which a conditioning agent com-prises 4-(fluoranthyl)-butanoic acid.
45. A process as in claim 2 in which a conditioning agent com-prises a cationic derivative of 4-(fluoranthyl)-butanoic acid.
46. A process as in claim 45 wherein said derivative was prepared by reaction of the acid with a polyamine.
47. A process as in claim 3 or 39, in which a conditioning agent com-prises a salt of 7-diethylamino-4-methylcoumarin.
48. A process for the separation of a mixture of particles containing differing concentrations of a selected component into first, second and third fractions, said process comprising the steps of:
a. conditioning the mixture of particles with at least one surface-active agent comprising a compound having both a selective functional group and a detectable moiety and having an affinity toward a selected component in the particles such that the surface-active agent selectively adheres to the selected component in the particles to provide a coating on the particles dependent upon the particles to the substantial exclusion of coated particles containing no appreciable concentration of the selected component; and b. separating the conditioned particles into three fractions by dis-tinguishing the degree of the detectable moiety on the surface of the condi-tioned particles, with a first fraction comprising particles exhibiting a relatively high surface content of said moiety, a second fraction comprising particles exhibiting a relative surface content of said moiety lower than particles in the first fraction and a third fraction comprising particles exhibiting a relative content of said moiety lower than particles in the second fraction.
a. conditioning the mixture of particles with at least one surface-active agent comprising a compound having both a selective functional group and a detectable moiety and having an affinity toward a selected component in the particles such that the surface-active agent selectively adheres to the selected component in the particles to provide a coating on the particles dependent upon the particles to the substantial exclusion of coated particles containing no appreciable concentration of the selected component; and b. separating the conditioned particles into three fractions by dis-tinguishing the degree of the detectable moiety on the surface of the condi-tioned particles, with a first fraction comprising particles exhibiting a relatively high surface content of said moiety, a second fraction comprising particles exhibiting a relative surface content of said moiety lower than particles in the first fraction and a third fraction comprising particles exhibiting a relative content of said moiety lower than particles in the second fraction.
49. The process of claim 48 wherein said particles comprise ore particles
50. A process for separating higher BTU coal particles from particulate coal comprising higher BTU coal particles and lower BTU particles, said process comprising:
a. treating the particulate coal with a detectable marking agent comprising both a surface-selective functional group and a detectable moiety to attach a greater amount of said marking agent preferentially to the higher BTU
coal particles or to the lower BTU particles; and b. thereafter separating particles carrying a greater amount of said marking agent from the particles carrying a lesser amount of said marking agent.
a. treating the particulate coal with a detectable marking agent comprising both a surface-selective functional group and a detectable moiety to attach a greater amount of said marking agent preferentially to the higher BTU
coal particles or to the lower BTU particles; and b. thereafter separating particles carrying a greater amount of said marking agent from the particles carrying a lesser amount of said marking agent.
51. A process for separation of higher surface kerogen content oil shale particles from lower surface kerogen content particles, said process comprising:
a. conditioning the surface of said particles with a conditioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, i. to selectively mark the kerogen on the surface of said particles to the substantial exclusion of the non-kerogen portion of the surface, or ii. to selectively mark the non-kerogen portion of the surface of said particles, to the substantial exclusion of the kerogen portion of the surface of said particles;
b. detecting the degree of marking on said particles; and c. separating particles having a desired degree of marking from particles having a lesser degree of marking.
a. conditioning the surface of said particles with a conditioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, i. to selectively mark the kerogen on the surface of said particles to the substantial exclusion of the non-kerogen portion of the surface, or ii. to selectively mark the non-kerogen portion of the surface of said particles, to the substantial exclusion of the kerogen portion of the surface of said particles;
b. detecting the degree of marking on said particles; and c. separating particles having a desired degree of marking from particles having a lesser degree of marking.
52. A process for separating particles of a first gangue mineral from particles of a second mineral in which there is distributed a third mineral, thereby concentrating the desired third mineral, said process comprising:
a. conditioning said particles with a conditioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively mark either:
i. the first gangue mineral or ii. the second mineral, to the substantial exclusion of the other;
b. detecting the marked particles; and, c. separating the detected, marked particles from the substantially unmarked particles.
a. conditioning said particles with a conditioning agent comprising a compound having both a surface-selective functional group and a detectable moiety, to selectively mark either:
i. the first gangue mineral or ii. the second mineral, to the substantial exclusion of the other;
b. detecting the marked particles; and, c. separating the detected, marked particles from the substantially unmarked particles.
53. The process of claim 2 wherein said surface-selective group comprises a chelating functional group.
54. The process of claim 53 wherein said chelating functional group is a metal-ion chelating group.
55. The process of claim 54 wherein said surface-selective group is 8-hydroxyquinoline or a derivative thereof.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000365877A CA1169816A (en) | 1980-12-01 | 1980-12-01 | Process using detectable marking compounds to sort particles |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000365877A CA1169816A (en) | 1980-12-01 | 1980-12-01 | Process using detectable marking compounds to sort particles |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1169816A true CA1169816A (en) | 1984-06-26 |
Family
ID=4118603
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000365877A Expired CA1169816A (en) | 1980-12-01 | 1980-12-01 | Process using detectable marking compounds to sort particles |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1169816A (en) |
-
1980
- 1980-12-01 CA CA000365877A patent/CA1169816A/en not_active Expired
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