CA1221842A - Treatment of ores - Google Patents
Treatment of oresInfo
- Publication number
- CA1221842A CA1221842A CA000455496A CA455496A CA1221842A CA 1221842 A CA1221842 A CA 1221842A CA 000455496 A CA000455496 A CA 000455496A CA 455496 A CA455496 A CA 455496A CA 1221842 A CA1221842 A CA 1221842A
- Authority
- CA
- Canada
- Prior art keywords
- solvent
- cyanide
- metals
- pyrite
- gold
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
Abstract
ABSTRACT OF THE DISCLOSURE
This invention relates to a process for the recovery of one or more of the metals gold, silver, copper, zinc, vanadium, germanium and cobalt from pyrite concentrate. The first step of the process comprises mixing pyrite concentrate with cyanide solvent so that the metals dissolve in the solvent. The solvent and pyrite slurry is then dewatered to yield pyrite free of the metals and a cyanide solvent containing the metals. The pyrite is separated from the cyanide solvent. A first stream of the cyanide solvent is recycled to the first step and a second stream of the cyanide solvent is passed through activated charcoal. The gold and some of the silver present in the solvent are adsorbed on the charcoal leaving the solvent barren in gold. At least one of the metals remaining in the solvent is extracted by means of ion exchange, leaving solvent and an eluate of cyanide waste. The cyanide waste is neutralized or destroyed and the solvent is recycled to the first step. The continuous nature of the process minimizes the quantity of water required and the pyrite is almost completely separated into its useful components, with minimal waste.
This invention relates to a process for the recovery of one or more of the metals gold, silver, copper, zinc, vanadium, germanium and cobalt from pyrite concentrate. The first step of the process comprises mixing pyrite concentrate with cyanide solvent so that the metals dissolve in the solvent. The solvent and pyrite slurry is then dewatered to yield pyrite free of the metals and a cyanide solvent containing the metals. The pyrite is separated from the cyanide solvent. A first stream of the cyanide solvent is recycled to the first step and a second stream of the cyanide solvent is passed through activated charcoal. The gold and some of the silver present in the solvent are adsorbed on the charcoal leaving the solvent barren in gold. At least one of the metals remaining in the solvent is extracted by means of ion exchange, leaving solvent and an eluate of cyanide waste. The cyanide waste is neutralized or destroyed and the solvent is recycled to the first step. The continuous nature of the process minimizes the quantity of water required and the pyrite is almost completely separated into its useful components, with minimal waste.
Description
~Z2~
TITI.E: TREATMENT OF ORES
INVENTORS: ARTHUR E. COBURN
ROGER DEAL
This invention relates to the field of the recovery of metals from pyrite, and more particularly to the efficient recovery of valuable metals from mine tailings and their separation into marketable metals in a way which is both economically and ecologically sound.
'~f~' ~
. ~
", , ~2Z~
I.arge quantities of solid waste material known as tailings are generated in mining, concentrating and smelt-ing ore. Many mines dispose of such tailings by impound-ing these materials ln settling ponds or basins. Such natural settling types of systems require large quantities of water and often involve pumping both the tailings and the water long distances. The creation of dumps means problems of possible stream pollution and has negative effects on farms, real-estate and land values.
It is well known that valuable metals can be recovered from waste by leaching. Tailings which were discarded in the past, in some cases may contain metal values eccnomically recoverable under changed market conditions. Such tailings may be reground, subjected to a flotation process and then leached. However a potential environmental hazard always exists due to the possibility that the leach solutions in the remaining waste could enter the ground water system from the storage location.
In addition, many jurisdictions now have laws governing the composition of waste products which are to be stored or disposed of.
It has now been found that pyrite may be almost completely separated into its valuable components, using a minimal amount of water and leaving a minimal amount of waste to be disposed of. Furthermore, said waste is in an ecologically acceptable form. So far as is known, no prior procedures have been known or utilized in which pyrite l'~Z~i~qL2 has been almost compLetely separated into its useful components economically and with minimal -~ater require~
ments and waste production~
This invention provides an improved closed loop waste treatment process for the recovery of metals from pyrite which minimizes the water required for the recovery and eliminates ecological hazards resulting from the storage of mine tailings. Because of its continuous nature, this invention does not require the treatment of water as the water can be reused due to the fact that essentially all of the metals are removed.
The present invention provides a process for the recovery of one or more of the metals gold, silver, copper, zinc, vanadium, germanium and cobalt from pyrite concen-trate, in which:
(a) the pyrite concentrate containing one or more of the metals gold, silver, copper, zinc, vanadium, germanium and cobalt is mixed with cyanide solvent so that the metals dissolve in the solvent;
~b) the solvent and pyrite mixture is subjected to treatment with reagents in a suitable apparatus to yield pyrite free of said metals and a cyanide solvent containing said metals;
(c) the pyrite is separated from the cyanide solvent;
I (d) a first stream of the cyanide solvent is recycled to step (a);
~ej a second stream of the cyanide solvent is passed through activated charcoal so that the gold and some of the silver are adsorbed on the charcoal leaving the solvent barren in gold;
(f) at least one of the metals remaining in the solvent is extracted by means of ion e~change providing cleaned solvent and an eluate of cyanide waste;
~g) the cyanide waste is neutralized or eliminated;
and (h~ the solvent from step (f) is recycled to step (a)-This invention will be better understood from a study of the following disclosure in which reference is directed to the attached drawing.
Figure 1 is a generally diagrammatic flowsheet illustrating the process of the invention, including optional steps.
The first step consists in dissolving the metals which arecontained by the pyrite. The pyrite concentrate in semi-dry or wet form, is preferably introduced into a flotation cell containing a cyanide solvent. Any cyanide compound such as potassium cyanide which releases cyanide ions when added to water may be used in a~ueous solution as the solvent. The mixture is agitated and then 'Ç3 1;2218~
the entire mixture is separated into solids and a liquid ln order to separate the now barren pyrite from the cyanide solvent which contains the dissolved metals. The separa-tion or so-called dewatering may be accomplished by using conventional devices and processes such as cyclones, gravity settling and overflow, plate separators, tube separators or filters. The barren pyrite may be stock-piled to allow the trace cyanide residues to decompose and may be later roasted to provide sulphur dioxide gas and iron oxide ore.
It is to be noted that conventionally cyanidation of ores is accomplished by pumping the ore and acqueous reagents into tanks with impellers for prolonged contact.
Although such a method could be used in the present inven-tion, it has been found that the utilization of a flota-tion cell to effect contact of the pyrite concentrate with the cyanide allows for more rapid removal of the valuable metals with improved efficiency. It is emphasized that such cells are not utilized in this process step for conventional froth flotation~
The pregnant cyanide solvent is transferred to a primary holding tank. From this holding tank a first stream of the cyanide solvent is circulated back into the flotation cell for contact with fresh metal-bearing pyrite concen-trate. Thus, the quantity of metal in the cyanidesolvent is increased resulting in a more concentrated 12'~
solution thus producing higher yield of metals per solvent processed. Furthermore, the recirculation of the solvent decreases the quantity of solvent required. It should be noted, however, that loss of solvent may occur in the removal of the now barren pyrite and accordingly the water and chemicals may have to be adjusted in the primary holding tank. The preferred cyanide solvent is an aqueous solution of sodium cyanide, sodium carbonate and hydrogen peroxide and the preferred composition to be maintained is 2~ sodium cyanide, 2% sodium carbonate and 0.6% hydrogen peroxide, by weight, in aqueous solution. Furthermore, the preferred ratio cf pyrite to solvent in the slurry is 65:35. So far as is known, the preferred composition of the solvent used in the present invention is novel as is the use of hydro-gen peroxide as an oxidant in cyanidation.
An optional concurrent step consists of processinga side stream of the cyanide solvent from the primary holding tank by ion exchange to remove calcium and magnesium.
This step is performed in order to avoid interference which may occur later in the process when there is a con-siderable amount of calcium andjor magnesium ~uild-up in the water used. The necessity of performing this step will vary with the degree of hardness of the water involved and usually this step will not be required in small batches.
Conventional equipment and method may be used for this process step. For example, the equipment may consist of 12ZPR~2 a hydrogen cation~exchan~er unit containing a cation-exchange resin in bead form, a dilute acid tank and a strong acid tank. Cations of calcium and magnesium are removed by exchanging hydrogen cations for them. Regen-eration is effected with a dilute acid such as sulfuric.
After being passed through the ion exchange equipment, the cyanide solvent is returned to the primary holding tank.
An essential step, which is performed concuxrently with the recirculation of the cyanide solvent from the primary holding tank to the flotation cell, is the transporting of the main stream of the cyanide solvent for the purpose of removing the dissolved valuable metals from the solvent. The major step in this process involves passing the cyanide solvent through activated charcoal according to conventional methods. Any commercial grade of activated charcoal may be used. The charcoal adsorbs the gold and silver cyanide compounds present in the solvent. When the charcoal's adsorption capacity is reached, the gold and silver are removed from the charcoal, for example by elution with an ethanolic solution of sodium hydroxide.
After being passed through the activated charcoal, the cyanide solvent may be subjected to further optional processes for the recovery of metals such as copper and zinc and additional silver.
Alternatively, any silver still retained by the 1~2~
cyanide solvent may be removed by introducing the solvent into a tank. The addition of a soluhle chloride salt precipitates the silver ion as silver chloride The cyanide solvent may then be passed on to the next step.
Metals including copper and ~inc may be removed from the cyanide solvent by passing the cyanide solvent through an electrolytic cell.
Following the above two optional steps or immediately upon the exit of the cyanide solvent from the activated charcoal, the solvent may be stored in a secondary holding tank. Concurrent streams of the solvent, now barren of gold, silver and most metals, lead out of this secondary tank. The first stream returns the solvent to the primary holding tank thereby closing the loop. The second stream lS is passed through an ion exchange unit for removal of trace quantities of any metals, such as vanadium, germanium and cobalt, remaining in the solvent. The solvent which passes through the ion exchange unit is returned to the primary holding tank for reuse.
The recovery of the trace metals by ion exchange results in the generation of a small quantity of cyanide waste which is destroyed or neutralized by conventional processes for environmentally safe discharge. For example, the pH of the cyanide waste may be increased and hydrogen peroxide added to produce carbon dioxide and nitrogen gas.
It is anticipated that this invention will be used ~2;~
g primarily to recover metals remaining in tailings of mineral dressing and similar processing of ores. Accord-ing]y, the feed pyrite for the process is not likely to consist of pyrite concentrate but rather of raw tailings containing pyrite. Under such circumstances additional steps, priorto the mixing of the pyrite with the cyanide solvent, are necessary for efficient use of the process.
These steps are identified as Stage 0 in Figure 1. In the first step of Stage 0, the tailings containing pyrite are screened and/or ground, formed into a slurry in water and introduced into a gravity separation device such as a sluice box. The preferred yravity separation device is a moving bed sluice device. The device separates the heavy mineral pyrite fraction from the liqhter silica and granite. The silica and granite are discarded while the pyrite fraction, still in slurry form, is passed to a concentrating or separation table. The concentrating table effects separation of the pyrite from the heavier mineral forms such as cassiterite and galena. The pyrite is then dewatered using a conventional device such as a cyclone with the water being cycled back to the gravity separation device for reuse with new feed. The pyrite which remains is relatively pure and is in moist form, ready to proceed to Step 1. This feed material usually has been ground to less than 60 mesh (Tyler standard scale~.
~ The invention will be better understood by reference 5L~
~2'~189L2 to the follo~7ing example.
Example:
The feed material used was ten pounds of copper tailings, that is the waste residue remaining after the copper minerals have been removed from ore. The tailings were less than 80 mesh (Tyler standard scale) in size.
These tailings were formed into a 50~ water slurry and passed through a moving bed sluice device. One pound of pyrite was collected and the remainder of the material discarded.
The one pound of pyrite, still in an approximately 50% water slurry, was passed over a separation table to remove any lead or tin bearing minerals present. No such minerals were present in this run.
The pyrite was then dewatered by leaving the pyrite sl~lrry in a beaker for a period of five minutes to allow natural settling of the pyrite fraction and decantation of the water fraction. The water decanted was reserved to be used in forming a subsequent batch of tailings into a water slurry.
One pound of wet pyrite remained in the beaker.
This pyrite was added to a flotation cell containing 500 ml of an aqueous solution consisting of 2% sodium cyanide,
TITI.E: TREATMENT OF ORES
INVENTORS: ARTHUR E. COBURN
ROGER DEAL
This invention relates to the field of the recovery of metals from pyrite, and more particularly to the efficient recovery of valuable metals from mine tailings and their separation into marketable metals in a way which is both economically and ecologically sound.
'~f~' ~
. ~
", , ~2Z~
I.arge quantities of solid waste material known as tailings are generated in mining, concentrating and smelt-ing ore. Many mines dispose of such tailings by impound-ing these materials ln settling ponds or basins. Such natural settling types of systems require large quantities of water and often involve pumping both the tailings and the water long distances. The creation of dumps means problems of possible stream pollution and has negative effects on farms, real-estate and land values.
It is well known that valuable metals can be recovered from waste by leaching. Tailings which were discarded in the past, in some cases may contain metal values eccnomically recoverable under changed market conditions. Such tailings may be reground, subjected to a flotation process and then leached. However a potential environmental hazard always exists due to the possibility that the leach solutions in the remaining waste could enter the ground water system from the storage location.
In addition, many jurisdictions now have laws governing the composition of waste products which are to be stored or disposed of.
It has now been found that pyrite may be almost completely separated into its valuable components, using a minimal amount of water and leaving a minimal amount of waste to be disposed of. Furthermore, said waste is in an ecologically acceptable form. So far as is known, no prior procedures have been known or utilized in which pyrite l'~Z~i~qL2 has been almost compLetely separated into its useful components economically and with minimal -~ater require~
ments and waste production~
This invention provides an improved closed loop waste treatment process for the recovery of metals from pyrite which minimizes the water required for the recovery and eliminates ecological hazards resulting from the storage of mine tailings. Because of its continuous nature, this invention does not require the treatment of water as the water can be reused due to the fact that essentially all of the metals are removed.
The present invention provides a process for the recovery of one or more of the metals gold, silver, copper, zinc, vanadium, germanium and cobalt from pyrite concen-trate, in which:
(a) the pyrite concentrate containing one or more of the metals gold, silver, copper, zinc, vanadium, germanium and cobalt is mixed with cyanide solvent so that the metals dissolve in the solvent;
~b) the solvent and pyrite mixture is subjected to treatment with reagents in a suitable apparatus to yield pyrite free of said metals and a cyanide solvent containing said metals;
(c) the pyrite is separated from the cyanide solvent;
I (d) a first stream of the cyanide solvent is recycled to step (a);
~ej a second stream of the cyanide solvent is passed through activated charcoal so that the gold and some of the silver are adsorbed on the charcoal leaving the solvent barren in gold;
(f) at least one of the metals remaining in the solvent is extracted by means of ion e~change providing cleaned solvent and an eluate of cyanide waste;
~g) the cyanide waste is neutralized or eliminated;
and (h~ the solvent from step (f) is recycled to step (a)-This invention will be better understood from a study of the following disclosure in which reference is directed to the attached drawing.
Figure 1 is a generally diagrammatic flowsheet illustrating the process of the invention, including optional steps.
The first step consists in dissolving the metals which arecontained by the pyrite. The pyrite concentrate in semi-dry or wet form, is preferably introduced into a flotation cell containing a cyanide solvent. Any cyanide compound such as potassium cyanide which releases cyanide ions when added to water may be used in a~ueous solution as the solvent. The mixture is agitated and then 'Ç3 1;2218~
the entire mixture is separated into solids and a liquid ln order to separate the now barren pyrite from the cyanide solvent which contains the dissolved metals. The separa-tion or so-called dewatering may be accomplished by using conventional devices and processes such as cyclones, gravity settling and overflow, plate separators, tube separators or filters. The barren pyrite may be stock-piled to allow the trace cyanide residues to decompose and may be later roasted to provide sulphur dioxide gas and iron oxide ore.
It is to be noted that conventionally cyanidation of ores is accomplished by pumping the ore and acqueous reagents into tanks with impellers for prolonged contact.
Although such a method could be used in the present inven-tion, it has been found that the utilization of a flota-tion cell to effect contact of the pyrite concentrate with the cyanide allows for more rapid removal of the valuable metals with improved efficiency. It is emphasized that such cells are not utilized in this process step for conventional froth flotation~
The pregnant cyanide solvent is transferred to a primary holding tank. From this holding tank a first stream of the cyanide solvent is circulated back into the flotation cell for contact with fresh metal-bearing pyrite concen-trate. Thus, the quantity of metal in the cyanidesolvent is increased resulting in a more concentrated 12'~
solution thus producing higher yield of metals per solvent processed. Furthermore, the recirculation of the solvent decreases the quantity of solvent required. It should be noted, however, that loss of solvent may occur in the removal of the now barren pyrite and accordingly the water and chemicals may have to be adjusted in the primary holding tank. The preferred cyanide solvent is an aqueous solution of sodium cyanide, sodium carbonate and hydrogen peroxide and the preferred composition to be maintained is 2~ sodium cyanide, 2% sodium carbonate and 0.6% hydrogen peroxide, by weight, in aqueous solution. Furthermore, the preferred ratio cf pyrite to solvent in the slurry is 65:35. So far as is known, the preferred composition of the solvent used in the present invention is novel as is the use of hydro-gen peroxide as an oxidant in cyanidation.
An optional concurrent step consists of processinga side stream of the cyanide solvent from the primary holding tank by ion exchange to remove calcium and magnesium.
This step is performed in order to avoid interference which may occur later in the process when there is a con-siderable amount of calcium andjor magnesium ~uild-up in the water used. The necessity of performing this step will vary with the degree of hardness of the water involved and usually this step will not be required in small batches.
Conventional equipment and method may be used for this process step. For example, the equipment may consist of 12ZPR~2 a hydrogen cation~exchan~er unit containing a cation-exchange resin in bead form, a dilute acid tank and a strong acid tank. Cations of calcium and magnesium are removed by exchanging hydrogen cations for them. Regen-eration is effected with a dilute acid such as sulfuric.
After being passed through the ion exchange equipment, the cyanide solvent is returned to the primary holding tank.
An essential step, which is performed concuxrently with the recirculation of the cyanide solvent from the primary holding tank to the flotation cell, is the transporting of the main stream of the cyanide solvent for the purpose of removing the dissolved valuable metals from the solvent. The major step in this process involves passing the cyanide solvent through activated charcoal according to conventional methods. Any commercial grade of activated charcoal may be used. The charcoal adsorbs the gold and silver cyanide compounds present in the solvent. When the charcoal's adsorption capacity is reached, the gold and silver are removed from the charcoal, for example by elution with an ethanolic solution of sodium hydroxide.
After being passed through the activated charcoal, the cyanide solvent may be subjected to further optional processes for the recovery of metals such as copper and zinc and additional silver.
Alternatively, any silver still retained by the 1~2~
cyanide solvent may be removed by introducing the solvent into a tank. The addition of a soluhle chloride salt precipitates the silver ion as silver chloride The cyanide solvent may then be passed on to the next step.
Metals including copper and ~inc may be removed from the cyanide solvent by passing the cyanide solvent through an electrolytic cell.
Following the above two optional steps or immediately upon the exit of the cyanide solvent from the activated charcoal, the solvent may be stored in a secondary holding tank. Concurrent streams of the solvent, now barren of gold, silver and most metals, lead out of this secondary tank. The first stream returns the solvent to the primary holding tank thereby closing the loop. The second stream lS is passed through an ion exchange unit for removal of trace quantities of any metals, such as vanadium, germanium and cobalt, remaining in the solvent. The solvent which passes through the ion exchange unit is returned to the primary holding tank for reuse.
The recovery of the trace metals by ion exchange results in the generation of a small quantity of cyanide waste which is destroyed or neutralized by conventional processes for environmentally safe discharge. For example, the pH of the cyanide waste may be increased and hydrogen peroxide added to produce carbon dioxide and nitrogen gas.
It is anticipated that this invention will be used ~2;~
g primarily to recover metals remaining in tailings of mineral dressing and similar processing of ores. Accord-ing]y, the feed pyrite for the process is not likely to consist of pyrite concentrate but rather of raw tailings containing pyrite. Under such circumstances additional steps, priorto the mixing of the pyrite with the cyanide solvent, are necessary for efficient use of the process.
These steps are identified as Stage 0 in Figure 1. In the first step of Stage 0, the tailings containing pyrite are screened and/or ground, formed into a slurry in water and introduced into a gravity separation device such as a sluice box. The preferred yravity separation device is a moving bed sluice device. The device separates the heavy mineral pyrite fraction from the liqhter silica and granite. The silica and granite are discarded while the pyrite fraction, still in slurry form, is passed to a concentrating or separation table. The concentrating table effects separation of the pyrite from the heavier mineral forms such as cassiterite and galena. The pyrite is then dewatered using a conventional device such as a cyclone with the water being cycled back to the gravity separation device for reuse with new feed. The pyrite which remains is relatively pure and is in moist form, ready to proceed to Step 1. This feed material usually has been ground to less than 60 mesh (Tyler standard scale~.
~ The invention will be better understood by reference 5L~
~2'~189L2 to the follo~7ing example.
Example:
The feed material used was ten pounds of copper tailings, that is the waste residue remaining after the copper minerals have been removed from ore. The tailings were less than 80 mesh (Tyler standard scale) in size.
These tailings were formed into a 50~ water slurry and passed through a moving bed sluice device. One pound of pyrite was collected and the remainder of the material discarded.
The one pound of pyrite, still in an approximately 50% water slurry, was passed over a separation table to remove any lead or tin bearing minerals present. No such minerals were present in this run.
The pyrite was then dewatered by leaving the pyrite sl~lrry in a beaker for a period of five minutes to allow natural settling of the pyrite fraction and decantation of the water fraction. The water decanted was reserved to be used in forming a subsequent batch of tailings into a water slurry.
One pound of wet pyrite remained in the beaker.
This pyrite was added to a flotation cell containing 500 ml of an aqueous solution consisting of 2% sodium cyanide,
2% sodium carbonate and 0.6% hydrogen peroxide by weight.
The material in the flotation cell was agitated for five ~ minutes after which the entire mixture was transferred into :
~2Zl~
a beaker and allowed to settle. After several minutes, the solution containing the dissolved metals was decanted off frorn the pyrite.
Thls solution was then pas~ed through a column of 16 mesh activated charcoal and the raffinate retained for further extraction. The column was subsequently eluted with an ethanolic solution of sodium hydroxide. An assay of thQ eluate showed a recovery of silver and gold corresponding to 1.02 oz./T and 0.04 oz./T
respectively, when extrapolated to ton quantities.
The raffinate from the previous step, was then passed through an ion exchange column containing IRA-400 (Rohm & Haas) resin and subsequently returned to the flotation cell. The column was eluted with 2N NaCN
solution. The eluate, when analysed, was found to contain 87 ppm of copper as well as traces of zinc, cobalt and nickel.
The material in the flotation cell was agitated for five ~ minutes after which the entire mixture was transferred into :
~2Zl~
a beaker and allowed to settle. After several minutes, the solution containing the dissolved metals was decanted off frorn the pyrite.
Thls solution was then pas~ed through a column of 16 mesh activated charcoal and the raffinate retained for further extraction. The column was subsequently eluted with an ethanolic solution of sodium hydroxide. An assay of thQ eluate showed a recovery of silver and gold corresponding to 1.02 oz./T and 0.04 oz./T
respectively, when extrapolated to ton quantities.
The raffinate from the previous step, was then passed through an ion exchange column containing IRA-400 (Rohm & Haas) resin and subsequently returned to the flotation cell. The column was eluted with 2N NaCN
solution. The eluate, when analysed, was found to contain 87 ppm of copper as well as traces of zinc, cobalt and nickel.
Claims (2)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
WE CLAIM:
1. An improved process for the recovery of one or more of the metals, gold, silver, copper, zinc, vanadium, germanium and cobalt from pyrite concentrate in ore tail-ings, which comprises the steps of:
(a) a rapid dissolution by cyanidation of one or more of the metals gold, silver, copper, zinc, vanadium, germanium and cobalt contained in a pyrite concentrate wherein the said ground pyrite concentrate is slurried in an alkaline cyanide and an alkaline carbonate bearing solvent in the presence of hydrogen peroxide, with contin-uous agitation;
(b) the pyrite concentrate slurried in the cyanide solution is separated to yield tailings barren of the said metals, and a pregnant cyanide solvent containing the said metals;
(c) a first stream of cyanide solvent is returned to step (a);
(d) a second stream of cyanide solvent is passed through activated charcoal to remove the gold cyanide compounds and some of the silver cyanide compounds dissolved therein;
(e) at least one of the metals remaining in the solvent is extracted by means of an ion exchange compound, yielding a cleaned solvent and an eluate of cyanide waste;
(f) the cyanide waste is neutralized or destroyed; and (g) the cleaned solvent from step (e) is recycled to step (a).
(a) a rapid dissolution by cyanidation of one or more of the metals gold, silver, copper, zinc, vanadium, germanium and cobalt contained in a pyrite concentrate wherein the said ground pyrite concentrate is slurried in an alkaline cyanide and an alkaline carbonate bearing solvent in the presence of hydrogen peroxide, with contin-uous agitation;
(b) the pyrite concentrate slurried in the cyanide solution is separated to yield tailings barren of the said metals, and a pregnant cyanide solvent containing the said metals;
(c) a first stream of cyanide solvent is returned to step (a);
(d) a second stream of cyanide solvent is passed through activated charcoal to remove the gold cyanide compounds and some of the silver cyanide compounds dissolved therein;
(e) at least one of the metals remaining in the solvent is extracted by means of an ion exchange compound, yielding a cleaned solvent and an eluate of cyanide waste;
(f) the cyanide waste is neutralized or destroyed; and (g) the cleaned solvent from step (e) is recycled to step (a).
2. A process as described in claim 1, in which the cyanide solvent slurried with the pyrite concentrate from ore tailings contains at least 2% sodium cyanide and at least 2% sodium carbonate and 0.6% hydrogen peroxide by weight in aqueous solution.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US50090083A | 1983-06-03 | 1983-06-03 | |
| US500,900 | 1983-06-03 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1221842A true CA1221842A (en) | 1987-05-19 |
Family
ID=23991395
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000455496A Expired CA1221842A (en) | 1983-06-03 | 1984-05-30 | Treatment of ores |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1221842A (en) |
Cited By (9)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0358004A2 (en) * | 1988-09-09 | 1990-03-14 | Degussa Aktiengesellschaft | Process for leaching noble metals using cyanidic solutions with hydrogen peroxide |
| WO1990013676A1 (en) * | 1989-04-28 | 1990-11-15 | Cra Services Limited | Recovery of gold and silver from complex refractory sulphide ores by cyanidisation and oxidation with peroxides |
| US4971625A (en) * | 1988-01-22 | 1990-11-20 | Degussa Aktiengesellschaft | Method for leaching gold and/or silver out of ores or out of ore-concentrates and also out of precious-metal wastes or precious-metal scrap by using cyanide-containing leaching solutions |
| GB2248633A (en) * | 1989-04-28 | 1992-04-15 | Cra Services | Recovery of gold and silver from complex refractory sulphide ores by cyanidisation and oxidation with peroxides |
| US5250272A (en) * | 1988-09-09 | 1993-10-05 | Degussa Aktiengesellschaft | Process for leaching precious metals with hydrogen-peroxide and a cyanide leaching solution |
| US5275791A (en) * | 1986-10-31 | 1994-01-04 | Degussa Aktiengesellschaft | Process for the leaching of gold and silver with cyanidic leaching solution and controlled addition of hydrogen peroxide |
| WO1995026418A1 (en) * | 1994-03-25 | 1995-10-05 | E.I. Du Pont De Nemours And Company | Hydrometallurgical extraction process |
| US5807421A (en) * | 1994-03-25 | 1998-09-15 | E. I. Du Pont De Nemours And Company | Hydrometallurgical extraction process |
| WO1999047714A1 (en) * | 1998-03-13 | 1999-09-23 | Lewis-Gray, Elizabeth, Beatrice, Gail | Apparatus and methods for recovering valuable metals |
-
1984
- 1984-05-30 CA CA000455496A patent/CA1221842A/en not_active Expired
Cited By (14)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5275791A (en) * | 1986-10-31 | 1994-01-04 | Degussa Aktiengesellschaft | Process for the leaching of gold and silver with cyanidic leaching solution and controlled addition of hydrogen peroxide |
| US4971625A (en) * | 1988-01-22 | 1990-11-20 | Degussa Aktiengesellschaft | Method for leaching gold and/or silver out of ores or out of ore-concentrates and also out of precious-metal wastes or precious-metal scrap by using cyanide-containing leaching solutions |
| US5250272A (en) * | 1988-09-09 | 1993-10-05 | Degussa Aktiengesellschaft | Process for leaching precious metals with hydrogen-peroxide and a cyanide leaching solution |
| EP0358004A2 (en) * | 1988-09-09 | 1990-03-14 | Degussa Aktiengesellschaft | Process for leaching noble metals using cyanidic solutions with hydrogen peroxide |
| EP0358004A3 (en) * | 1988-09-09 | 1990-04-25 | Degussa Aktiengesellschaft | Process for leaching noble metals using cyanidic solutions with hydrogen peroxide |
| WO1990013676A1 (en) * | 1989-04-28 | 1990-11-15 | Cra Services Limited | Recovery of gold and silver from complex refractory sulphide ores by cyanidisation and oxidation with peroxides |
| GB2248633A (en) * | 1989-04-28 | 1992-04-15 | Cra Services | Recovery of gold and silver from complex refractory sulphide ores by cyanidisation and oxidation with peroxides |
| GB2248633B (en) * | 1989-04-28 | 1993-03-17 | Cra Services | Recovery of gold and silver from complex refractory sulphide ores by cyanidisation and oxidation with peroxides |
| US5262136A (en) * | 1989-04-28 | 1993-11-16 | Cra Services Limited | Recovery of gold and silver from complex refractory sulphide ores by cyanidisation and oxidation with peroxides |
| WO1995026418A1 (en) * | 1994-03-25 | 1995-10-05 | E.I. Du Pont De Nemours And Company | Hydrometallurgical extraction process |
| AU679356B2 (en) * | 1994-03-25 | 1997-06-26 | E.I. Du Pont De Nemours And Company | Hydrometallurgical extraction process |
| US5807421A (en) * | 1994-03-25 | 1998-09-15 | E. I. Du Pont De Nemours And Company | Hydrometallurgical extraction process |
| WO1999047714A1 (en) * | 1998-03-13 | 1999-09-23 | Lewis-Gray, Elizabeth, Beatrice, Gail | Apparatus and methods for recovering valuable metals |
| US6613271B1 (en) | 1998-03-13 | 2003-09-02 | Alexander Hamilton Lewis-Gray | Apparatus and methods for recovering valuable metals |
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