CA1201422A - Process for the recovery of aluminum and iron salts from acidic waste waters - Google Patents
Process for the recovery of aluminum and iron salts from acidic waste watersInfo
- Publication number
- CA1201422A CA1201422A CA000425803A CA425803A CA1201422A CA 1201422 A CA1201422 A CA 1201422A CA 000425803 A CA000425803 A CA 000425803A CA 425803 A CA425803 A CA 425803A CA 1201422 A CA1201422 A CA 1201422A
- Authority
- CA
- Canada
- Prior art keywords
- waste waters
- liter
- sodium
- ferric oxide
- oxide hydrate
- 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
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F9/00—Multistage treatment of water, waste water or sewage
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B33/00—Silicon; Compounds thereof
- C01B33/20—Silicates
- C01B33/26—Aluminium-containing silicates, i.e. silico-aluminates
- C01B33/28—Base exchange silicates, e.g. zeolites
- C01B33/2807—Zeolitic silicoaluminates with a tridimensional crystalline structure possessing molecular sieve properties; Isomorphous compounds wherein a part of the aluminium ore of the silicon present may be replaced by other elements such as gallium, germanium, phosphorus; Preparation of zeolitic molecular sieves from molecular sieves of another type or from preformed reacting mixtures
- C01B33/2815—Zeolitic silicoaluminates with a tridimensional crystalline structure possessing molecular sieve properties; Isomorphous compounds wherein a part of the aluminium ore of the silicon present may be replaced by other elements such as gallium, germanium, phosphorus; Preparation of zeolitic molecular sieves from molecular sieves of another type or from preformed reacting mixtures of type A (UNION CARBIDE trade name; corresponds to GRACE's types Z-12 or Z-12L)
- C01B33/2823—Zeolitic silicoaluminates with a tridimensional crystalline structure possessing molecular sieve properties; Isomorphous compounds wherein a part of the aluminium ore of the silicon present may be replaced by other elements such as gallium, germanium, phosphorus; Preparation of zeolitic molecular sieves from molecular sieves of another type or from preformed reacting mixtures of type A (UNION CARBIDE trade name; corresponds to GRACE's types Z-12 or Z-12L) from aqueous solutions of an alkali metal aluminate and an alkali metal silicate excluding any other source of alumina or silica
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
- C01B39/00—Compounds having molecular sieve and base-exchange properties, e.g. crystalline zeolites; Their preparation; After-treatment, e.g. ion-exchange or dealumination
- C01B39/02—Crystalline aluminosilicate zeolites; Isomorphous compounds thereof; Direct preparation thereof; Preparation thereof starting from a reaction mixture containing a crystalline zeolite of another type, or from preformed reactants; After-treatment thereof
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/52—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities
- C02F1/5236—Treatment of water, waste water, or sewage by flocculation or precipitation of suspended impurities using inorganic agents
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F1/00—Treatment of water, waste water, or sewage
- C02F1/66—Treatment of water, waste water, or sewage by neutralisation; pH adjustment
-
- C—CHEMISTRY; METALLURGY
- C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
- C10K—PURIFYING OR MODIFYING THE CHEMICAL COMPOSITION OF COMBUSTIBLE GASES CONTAINING CARBON MONOXIDE
- C10K1/00—Purifying combustible gases containing carbon monoxide
- C10K1/20—Purifying combustible gases containing carbon monoxide by treating with solids; Regenerating spent purifying masses
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/20—Heavy metals or heavy metal compounds
- C02F2101/203—Iron or iron compound
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Engineering & Computer Science (AREA)
- Hydrology & Water Resources (AREA)
- Environmental & Geological Engineering (AREA)
- Water Supply & Treatment (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Combustion & Propulsion (AREA)
- Materials Engineering (AREA)
- General Chemical & Material Sciences (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Silicates, Zeolites, And Molecular Sieves (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
- Processing Of Solid Wastes (AREA)
- Manufacture And Refinement Of Metals (AREA)
- Removal Of Specific Substances (AREA)
- Separation Of Suspended Particles By Flocculating Agents (AREA)
- Compounds Of Iron (AREA)
- Solid-Sorbent Or Filter-Aiding Compositions (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Aluminum and iron salts contained in acidic waste waters are recovered by precipitation by means of an alkaline earth precipitating agent. The precipitate in the form of alumi-num hydroxide and ferric oxide hydrate is separated from the supernatant liquid and the aluminum hydroxide is leached out of the ferric oxide precipitate by treatment with sodium hydroxide.
The sodium hydroxide converts the aluminum hydroxide over to sodium aluminate which is further treated with sodium silicate and additional sodium hydroxide to form a crystalline zeolite.
The remaining iron oxide hydrate is washed and dried and may be pelleted for use as a gas purification substance or calcined to to the iron oxide for use as a pigment.
Aluminum and iron salts contained in acidic waste waters are recovered by precipitation by means of an alkaline earth precipitating agent. The precipitate in the form of alumi-num hydroxide and ferric oxide hydrate is separated from the supernatant liquid and the aluminum hydroxide is leached out of the ferric oxide precipitate by treatment with sodium hydroxide.
The sodium hydroxide converts the aluminum hydroxide over to sodium aluminate which is further treated with sodium silicate and additional sodium hydroxide to form a crystalline zeolite.
The remaining iron oxide hydrate is washed and dried and may be pelleted for use as a gas purification substance or calcined to to the iron oxide for use as a pigment.
Description
" 1201~2~
The present invention concerns a process for the recovery of aluminum and iron salts from acidic waste waters.
It was previously usual practice either to neutralize such acidic waste waters and to direct them to the river, or to discharge them into the sea.
These methods, however, are risky on the grounds of environmental protection. They have ~he further disadvantage that the materials contained in the acidic was~e waters, especially aluminum and iron, can be no longer used.
Other possible methods, therefore, have been sought.
For example, the acidic waste waters accumulating with the production of clay are being used for the treatm~nt of indus-trial and community waste waters, along with active bentonite as an inor~anic precipitation-, flocculation-, separation and absorbtion means.
This utilizes only a comparatively small frac~ion of the accumulated acidic waste waters.
The inven~ion is based on the problem of finding a process for the recovery of aluminum and iron salts from acidic waste waters, whereby not only can the previous environment-ally harmul practices be eliminated, but the substances con-tained in the waste waters can also be transformed into in-dustrially useful products.
The subject of the invention is thus a process for the recovery of aluminum and iron salts from acidic waste waters, characterized in that:
A. the acidic waste waters are neutrali~ed with calcium oxide and/or calcium hydroxide or the precipitation of aluminum hydroxide and iron (III) oxide hydrate;
~.201gL~Z
B. the aluminum hydroxide-iron (III) hydroxide precipitate obtained is treated with sodium hydroxide until the aluminum hydroxide dissolves as sodium aluminate;
C. the remaining iron (III) oxide hydrate precipitate is separated from the sodium aluminate solution, washed, and dried, the iron (III) oxide hydrate is pellated for use as a gas purification substance or converted by thermal treat-ment to an iron (III) oxide suitable for use as a pigment;
D. and the sodium aluminate solu~ion is trans~ormed into a crystalline zeolite by conversion with a water-glass solution.
With the recoverable acidic waste waters, according to the invention, the first concern is with waste waters accumulating with the clay extration. Such waste waters usually contain small quantities of colloidal silicic acid.
These particles of colloidal silicic acid evidently act as crystallization nuclei in the zeolite formation (step D).
Since it is seen surprisin~ly, that the æeolite formation proceeds more slowly when the sodium aluminate solution is free of silicic acid.
The reasons for the improved crystal formation arc, however, still not known exactly. The fact is that zeolite formation is improved to a surprising degree if silicic acid is present.
In general, the acidic waste waters used (from the clay production) have the following analytic composition:
A13~ 12 - 16 g/liter Fe3+ 4 _ 6 g/liter c~2+ 2 _ ~ g/liter Mg2~ 2 - 4 g/liter SiO2 0.2 _ 0.4 g/li~er ~z~ z Cl- ~5 - 90 g/liter fr~e HGl 4 - 6 g/liter The acidic waste waters in step A are neutralized to a pH value of 3-8, preferably 6.6 - 6.7.
In the case where the iron salt or a part of the iron salt in the waster water is present in the divalent condition, the precipitation in step A occurs in a suitable manner when the waste water is brought into contact with a gas containing oxygen. In general, air is blown through the solution to achieve this; the iron (III) oxide hydrate thus obtained is especially well suited as a gas purification substance.
The preferred waste waters used contain aluminum and iron (and sometimes other metals) in the form of the corres-ponding chlorides. They also contain some free HCl.
The starting materials can, however, be waste waters containing sulfuric acid, in which case a preneutralization is carried out before step A with calcium oxide and/or cal-cium hydroxide, by adjusting the pH to a value of about 3.
Then the separated calcium sulfate is filtered off.
The scope of the invention includes additionally the use of the iron (III) oxide hydrate produced according to step C as a gas purification substance, or the use of the iron (III) oxide produced thereby as pigment. The scope of the invention includes also the use of the ziolite produced according to step D as a molecul.ar sieve or as an adsorption material.
The zeolite obtained is primarily a Y-zeolite, which, as previously explained, evidently as formed because of the presenc~ of the so-called "nucleus formation substances" in a well-crystallized form. With the same resulting materials, zeolites of the A- and Y- types are also produced.
lZ014,2Z
The precipitation of aluminum hydroxide and of iron (III) oxide hydrate in step A is, in general, carried out as follows:
The waste waters containing hydrochloric acid, alum-inum chloride, and iron chloride are first heated by a blast of superheated steam, to just below the boiling point. With further blasts of steam, the pH is adjusted to about 6.6, whereby a mixture of aluminum hydroxide and iron (III) oxide hydrate precipitates.
The treatment of the aluminum hydroxide-iron (III) oxide hydrate precipitated with sodium hydroxide in step B
is generally carried out as follows:
After filtering and washing the hydroxide precipitate, sodium hydroxide is added to the hydroxide mixture, and the aluminum hydroxide is converted into sodiu~ aluminate.
The further treatment of the iron (III) oxide hydrate in step C is as follows:
The iron (III) oxide hydrate is filtered from the dis-solved aluminate and washed to be free of all aluminates.
The drying of the materials for the gas purification takes place at 60-llO~C. In industrial use, the iron (III) oxidP
hydrate is formed into pellets with the addition of a pres-sing aid ~or removal of hydrogen sulfide from gas mixtures.
The iron (III) oxide to be used as pi~ment is obtained by calcining the oxide hydrate at 600~C.
The iron (III) oxide hydrate obtained according to the invention is especially well-suited for gas purification, i.e., for the removal of hydrogen sulfide from diverse gas mixtures.
For the gas purification, the gases containing H2S
are led over the pelleted iron (III) o~ide hydrate substances lZ0~42~
placed in the reactors. The more or less strongly hydrated iron oxide reacts with the hydrogen sulfide according to the following equation:
Fe2O3 + 3H2S = Fe2S3 + 3H2O + 14.9 kcal The conversion of the sodium aluminate solution obtained in step D into a crystalline Y-zeolite is carried out, in general, as follows:
Following known procedures, a crystallized Y-zeolite is obtained by producing a suspension of nuclei for crystal formation is produced by the reaction of sodium aluminate with sodium silicate with an excess of caustic soda; the suspension is then ~onverted with sodium silicate to a zeolite having a SiO2/ A1203 mole ratio of abou~ 5:1.
Through the "SiO2-contamination" in the aluminate ob-tained from the acid waste water, the crystal nucleus forma-tion seems to be improved, so that the time necessary for the crystallization of the zeolite can be greatly shortened.
The same is true for the production of zeolites of the A- and X types.
The invention is in no way limited by the following examples:
1500 liters of clay-deco~pensation solution, contain-ing hydrochloric acid, (17.7 g/liter A12O3, 8.6 g/liter Fe23) are stirred strongly with 66 kg CaO to a pH of 6.7. Then 50g of flocculating agent, dissolved in 5 liters of water, is added to improve the filterability of the resulting hydro-xide [Al (OH)3 or Fe(OH)3].
After a reaction time of 4 hours, the hydroxide mixture is filtered off in a filter pr~ss.
1;2~)~9~2~
The filter cake (512 kg hydroxide mixture witn 90%
H2O) is added to 30 kg NaOH flakes, which are contained in a container of corrosion-resistant steel. The liquefying mix-ture is then heated and held for one hour at 90-95C.
After cooling to 80C, the sodium aluminate solution is separated from the iron oxide in the filter press.
631 kg of sodium aluminate solution (3.3% A12O3, 3.55% Na2O) is mixed with 169 kg NaOH (50% solution) and 29 kg NaOH flakes, so that 830 kg of a solution with 2.5%
A12O3 and 14.5% NaOH results.
The aluminate solution (830 kg) cooled at 20-25C, is then added to 265.6 kg of sodium water glass (41 Be~
28.6% SiO2) wi~h intensive stirring. From the clear solu-tion the suspension of nuclei for the ~rystal formation is formed after a short time. After 20 minutes of stirring and warming to 40~C~ the substance is filtered and washed.
301 kg of this filtered substance (dry substance 26%) is stirred with 421 kg sodium water glass (41Be), 145 kg NaOH (7.5% solution), and 90 kg of water, heated to 98C
and held at this temperature for 4 hours.
After this reaction time, a crystallized Y-zeolite with a crystallinity of 100% is formed.
1500 liters of clay-decompensation solution contain-ing sulfuric acid 517.7 g/liter A1~03, 8.6 g/liter Fe2O3) is adjusted by the addition of calcium oxide under strong stir-rin~ to a pH value of 3. The precipitated calcium sulfate is then separated o~er a filter press, and the filtrate is brought up to a pH of 6.6 by the further addition of CaO.
T~e hydroxides of aluminum and iron are filtered after the addition of 50 g of flocculating agents dissolved ~ Z~ ~2~
in 5 liters of water, and processed further as in Example 1, with a reaction time of 4 hours.
The accumulated iron (III) oxide hydrate still con-tains some calcium sulfate, which, however, does not impair the efficacy for H2S-removal.
The Y-zeolite obtained by this prscess has, in any case, a crystallinity of 100% ater a reaction time of 4 ours.
1 liter of a sodium aluminate solution with 33 g/li-ter A12O3 and 47 g/liter Na2O is stirred strongly into 1 liter of an 80C sodium silicate solution with 81 g/liter SiO2 and 24 g/liter Na2O. The sodium aluminate solution is produced as described in Example 1 and increased to the de-sired Na20 content with sodium hydroxide.
After 8 hours of reaction time at 80C, while it is stirred s~owly, the resulting A-zeolite is filtered, washed and dried (to about 20% water of hydration). A crystallized A-zeolite with calcium bonding capacity of 130 g Ca/g of water-free product is obtained.
For the synthesis of a zeolite of the Y-type, a sodium silicate solution with 83.5 g Na2O/liter and 62 g SiO2/liter is heated to 95C and mixed intensively with a sodium aluminate solution containing 71 g Na2O/liter, or 66 g A12O3/liter, and also heated to 95C. The sodium alum-inate solution obtained according to Example l ~33 g A12O3/
liter or 35.5 g Na2O/liter) must be evaporated by half in order to obtain the necessary Na20/A12O3 ratio. The mole ratio of SiO2tA12O3 of the component mixture amounts to 2.5.
lZ01~22 Also, the mole ratio of Na20/SiO2 is 2, and the mole ratio of Na20/A1203 is 5.
After a reaction time of 2 hours twithout stirring), the crystallized zeolite is iltered, washed and dried.
EXAMPLE OF APPLICATION
To demonstrate the effectiveness of the iron (III) oxide hydrate, obtained according to the invention, as a gas purification substance, a gas composed of 4 vol.% hydrogen sulfide, 42 vol.% CO2, 52 vol.% methane, and 2 volO% water, at room temperature, with a space velocity of about 9G0/hr, is passed over 500 ml of the iron ~III) oxide hydrate, ob-tained according to Example 1, which is in a stationary reactor; after 5 hours, the sulfur content of the substance is analytic~lly determined.
The sulfur content amounts to 35%. In comparison thereto, about 30% is measured with known gas purification substances.
The present invention concerns a process for the recovery of aluminum and iron salts from acidic waste waters.
It was previously usual practice either to neutralize such acidic waste waters and to direct them to the river, or to discharge them into the sea.
These methods, however, are risky on the grounds of environmental protection. They have ~he further disadvantage that the materials contained in the acidic was~e waters, especially aluminum and iron, can be no longer used.
Other possible methods, therefore, have been sought.
For example, the acidic waste waters accumulating with the production of clay are being used for the treatm~nt of indus-trial and community waste waters, along with active bentonite as an inor~anic precipitation-, flocculation-, separation and absorbtion means.
This utilizes only a comparatively small frac~ion of the accumulated acidic waste waters.
The inven~ion is based on the problem of finding a process for the recovery of aluminum and iron salts from acidic waste waters, whereby not only can the previous environment-ally harmul practices be eliminated, but the substances con-tained in the waste waters can also be transformed into in-dustrially useful products.
The subject of the invention is thus a process for the recovery of aluminum and iron salts from acidic waste waters, characterized in that:
A. the acidic waste waters are neutrali~ed with calcium oxide and/or calcium hydroxide or the precipitation of aluminum hydroxide and iron (III) oxide hydrate;
~.201gL~Z
B. the aluminum hydroxide-iron (III) hydroxide precipitate obtained is treated with sodium hydroxide until the aluminum hydroxide dissolves as sodium aluminate;
C. the remaining iron (III) oxide hydrate precipitate is separated from the sodium aluminate solution, washed, and dried, the iron (III) oxide hydrate is pellated for use as a gas purification substance or converted by thermal treat-ment to an iron (III) oxide suitable for use as a pigment;
D. and the sodium aluminate solu~ion is trans~ormed into a crystalline zeolite by conversion with a water-glass solution.
With the recoverable acidic waste waters, according to the invention, the first concern is with waste waters accumulating with the clay extration. Such waste waters usually contain small quantities of colloidal silicic acid.
These particles of colloidal silicic acid evidently act as crystallization nuclei in the zeolite formation (step D).
Since it is seen surprisin~ly, that the æeolite formation proceeds more slowly when the sodium aluminate solution is free of silicic acid.
The reasons for the improved crystal formation arc, however, still not known exactly. The fact is that zeolite formation is improved to a surprising degree if silicic acid is present.
In general, the acidic waste waters used (from the clay production) have the following analytic composition:
A13~ 12 - 16 g/liter Fe3+ 4 _ 6 g/liter c~2+ 2 _ ~ g/liter Mg2~ 2 - 4 g/liter SiO2 0.2 _ 0.4 g/li~er ~z~ z Cl- ~5 - 90 g/liter fr~e HGl 4 - 6 g/liter The acidic waste waters in step A are neutralized to a pH value of 3-8, preferably 6.6 - 6.7.
In the case where the iron salt or a part of the iron salt in the waster water is present in the divalent condition, the precipitation in step A occurs in a suitable manner when the waste water is brought into contact with a gas containing oxygen. In general, air is blown through the solution to achieve this; the iron (III) oxide hydrate thus obtained is especially well suited as a gas purification substance.
The preferred waste waters used contain aluminum and iron (and sometimes other metals) in the form of the corres-ponding chlorides. They also contain some free HCl.
The starting materials can, however, be waste waters containing sulfuric acid, in which case a preneutralization is carried out before step A with calcium oxide and/or cal-cium hydroxide, by adjusting the pH to a value of about 3.
Then the separated calcium sulfate is filtered off.
The scope of the invention includes additionally the use of the iron (III) oxide hydrate produced according to step C as a gas purification substance, or the use of the iron (III) oxide produced thereby as pigment. The scope of the invention includes also the use of the ziolite produced according to step D as a molecul.ar sieve or as an adsorption material.
The zeolite obtained is primarily a Y-zeolite, which, as previously explained, evidently as formed because of the presenc~ of the so-called "nucleus formation substances" in a well-crystallized form. With the same resulting materials, zeolites of the A- and Y- types are also produced.
lZ014,2Z
The precipitation of aluminum hydroxide and of iron (III) oxide hydrate in step A is, in general, carried out as follows:
The waste waters containing hydrochloric acid, alum-inum chloride, and iron chloride are first heated by a blast of superheated steam, to just below the boiling point. With further blasts of steam, the pH is adjusted to about 6.6, whereby a mixture of aluminum hydroxide and iron (III) oxide hydrate precipitates.
The treatment of the aluminum hydroxide-iron (III) oxide hydrate precipitated with sodium hydroxide in step B
is generally carried out as follows:
After filtering and washing the hydroxide precipitate, sodium hydroxide is added to the hydroxide mixture, and the aluminum hydroxide is converted into sodiu~ aluminate.
The further treatment of the iron (III) oxide hydrate in step C is as follows:
The iron (III) oxide hydrate is filtered from the dis-solved aluminate and washed to be free of all aluminates.
The drying of the materials for the gas purification takes place at 60-llO~C. In industrial use, the iron (III) oxidP
hydrate is formed into pellets with the addition of a pres-sing aid ~or removal of hydrogen sulfide from gas mixtures.
The iron (III) oxide to be used as pi~ment is obtained by calcining the oxide hydrate at 600~C.
The iron (III) oxide hydrate obtained according to the invention is especially well-suited for gas purification, i.e., for the removal of hydrogen sulfide from diverse gas mixtures.
For the gas purification, the gases containing H2S
are led over the pelleted iron (III) o~ide hydrate substances lZ0~42~
placed in the reactors. The more or less strongly hydrated iron oxide reacts with the hydrogen sulfide according to the following equation:
Fe2O3 + 3H2S = Fe2S3 + 3H2O + 14.9 kcal The conversion of the sodium aluminate solution obtained in step D into a crystalline Y-zeolite is carried out, in general, as follows:
Following known procedures, a crystallized Y-zeolite is obtained by producing a suspension of nuclei for crystal formation is produced by the reaction of sodium aluminate with sodium silicate with an excess of caustic soda; the suspension is then ~onverted with sodium silicate to a zeolite having a SiO2/ A1203 mole ratio of abou~ 5:1.
Through the "SiO2-contamination" in the aluminate ob-tained from the acid waste water, the crystal nucleus forma-tion seems to be improved, so that the time necessary for the crystallization of the zeolite can be greatly shortened.
The same is true for the production of zeolites of the A- and X types.
The invention is in no way limited by the following examples:
1500 liters of clay-deco~pensation solution, contain-ing hydrochloric acid, (17.7 g/liter A12O3, 8.6 g/liter Fe23) are stirred strongly with 66 kg CaO to a pH of 6.7. Then 50g of flocculating agent, dissolved in 5 liters of water, is added to improve the filterability of the resulting hydro-xide [Al (OH)3 or Fe(OH)3].
After a reaction time of 4 hours, the hydroxide mixture is filtered off in a filter pr~ss.
1;2~)~9~2~
The filter cake (512 kg hydroxide mixture witn 90%
H2O) is added to 30 kg NaOH flakes, which are contained in a container of corrosion-resistant steel. The liquefying mix-ture is then heated and held for one hour at 90-95C.
After cooling to 80C, the sodium aluminate solution is separated from the iron oxide in the filter press.
631 kg of sodium aluminate solution (3.3% A12O3, 3.55% Na2O) is mixed with 169 kg NaOH (50% solution) and 29 kg NaOH flakes, so that 830 kg of a solution with 2.5%
A12O3 and 14.5% NaOH results.
The aluminate solution (830 kg) cooled at 20-25C, is then added to 265.6 kg of sodium water glass (41 Be~
28.6% SiO2) wi~h intensive stirring. From the clear solu-tion the suspension of nuclei for the ~rystal formation is formed after a short time. After 20 minutes of stirring and warming to 40~C~ the substance is filtered and washed.
301 kg of this filtered substance (dry substance 26%) is stirred with 421 kg sodium water glass (41Be), 145 kg NaOH (7.5% solution), and 90 kg of water, heated to 98C
and held at this temperature for 4 hours.
After this reaction time, a crystallized Y-zeolite with a crystallinity of 100% is formed.
1500 liters of clay-decompensation solution contain-ing sulfuric acid 517.7 g/liter A1~03, 8.6 g/liter Fe2O3) is adjusted by the addition of calcium oxide under strong stir-rin~ to a pH value of 3. The precipitated calcium sulfate is then separated o~er a filter press, and the filtrate is brought up to a pH of 6.6 by the further addition of CaO.
T~e hydroxides of aluminum and iron are filtered after the addition of 50 g of flocculating agents dissolved ~ Z~ ~2~
in 5 liters of water, and processed further as in Example 1, with a reaction time of 4 hours.
The accumulated iron (III) oxide hydrate still con-tains some calcium sulfate, which, however, does not impair the efficacy for H2S-removal.
The Y-zeolite obtained by this prscess has, in any case, a crystallinity of 100% ater a reaction time of 4 ours.
1 liter of a sodium aluminate solution with 33 g/li-ter A12O3 and 47 g/liter Na2O is stirred strongly into 1 liter of an 80C sodium silicate solution with 81 g/liter SiO2 and 24 g/liter Na2O. The sodium aluminate solution is produced as described in Example 1 and increased to the de-sired Na20 content with sodium hydroxide.
After 8 hours of reaction time at 80C, while it is stirred s~owly, the resulting A-zeolite is filtered, washed and dried (to about 20% water of hydration). A crystallized A-zeolite with calcium bonding capacity of 130 g Ca/g of water-free product is obtained.
For the synthesis of a zeolite of the Y-type, a sodium silicate solution with 83.5 g Na2O/liter and 62 g SiO2/liter is heated to 95C and mixed intensively with a sodium aluminate solution containing 71 g Na2O/liter, or 66 g A12O3/liter, and also heated to 95C. The sodium alum-inate solution obtained according to Example l ~33 g A12O3/
liter or 35.5 g Na2O/liter) must be evaporated by half in order to obtain the necessary Na20/A12O3 ratio. The mole ratio of SiO2tA12O3 of the component mixture amounts to 2.5.
lZ01~22 Also, the mole ratio of Na20/SiO2 is 2, and the mole ratio of Na20/A1203 is 5.
After a reaction time of 2 hours twithout stirring), the crystallized zeolite is iltered, washed and dried.
EXAMPLE OF APPLICATION
To demonstrate the effectiveness of the iron (III) oxide hydrate, obtained according to the invention, as a gas purification substance, a gas composed of 4 vol.% hydrogen sulfide, 42 vol.% CO2, 52 vol.% methane, and 2 volO% water, at room temperature, with a space velocity of about 9G0/hr, is passed over 500 ml of the iron ~III) oxide hydrate, ob-tained according to Example 1, which is in a stationary reactor; after 5 hours, the sulfur content of the substance is analytic~lly determined.
The sulfur content amounts to 35%. In comparison thereto, about 30% is measured with known gas purification substances.
Claims (10)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the recovery of aluminum and iron salts from acidic waste waters and the production of alumino-silicate crystalline zeolites from the removed aluminum salts which comprises the steps of:
(a) adding an alkaline-precipitating agent comprising the oxides or hydroxides of calcium to said waste waters to adjust the pH of said waste waters;
(b) precipitating aluminum hydroxide and trivalent ferric oxide hydrate from said waste waters and separating said aluminum hydroxide and ferric oxide hydrate from the treated waste water;
(c) treating the aluminum hydroxide-ferric oxide pre-cipitate with sodium hydroxide to leach out the aluminum hydroxide by converting it to sodium aluminate;
(d) separating the ferric oxide hydrate precipitate from the sodium aluminate solution; and (e) reacting said sodium aluminate solution with sodium silicate to form a crystalline alumino-silicate zeolite.
(a) adding an alkaline-precipitating agent comprising the oxides or hydroxides of calcium to said waste waters to adjust the pH of said waste waters;
(b) precipitating aluminum hydroxide and trivalent ferric oxide hydrate from said waste waters and separating said aluminum hydroxide and ferric oxide hydrate from the treated waste water;
(c) treating the aluminum hydroxide-ferric oxide pre-cipitate with sodium hydroxide to leach out the aluminum hydroxide by converting it to sodium aluminate;
(d) separating the ferric oxide hydrate precipitate from the sodium aluminate solution; and (e) reacting said sodium aluminate solution with sodium silicate to form a crystalline alumino-silicate zeolite.
2. A process, as defined in Claim 1, the further steps of:
(a) washing and drying the precipitated ferric oxide hydrate;
(b) pelleting the dried ferric oxide hydrate precipitate for use as an adsorbant for hydrogen sulfide.
(a) washing and drying the precipitated ferric oxide hydrate;
(b) pelleting the dried ferric oxide hydrate precipitate for use as an adsorbant for hydrogen sulfide.
3. A process, as defined in Claim 1, the further steps of:
(a) washing and drying the ferric oxide hydrate pre-cipitate;
(b) calcining the dry material to convert it to the oxide for industrial use.
(a) washing and drying the ferric oxide hydrate pre-cipitate;
(b) calcining the dry material to convert it to the oxide for industrial use.
4. A process, as defined in Claim 1, in which the steps of reacting said sodium aluminate solution with sodium silicate includes:
(a) mixing the separated sodium aluminate solution with sodium silicate until a suspension of crystal-forming nuclei forms;
(b) filtering this suspension;
(c) mixing said filtered material with additional sodium silicate and sodium hydroxide; and (d) maintaining this mixture under crystalline growth conditions for sufficient time to form crystalline zeolites.
(a) mixing the separated sodium aluminate solution with sodium silicate until a suspension of crystal-forming nuclei forms;
(b) filtering this suspension;
(c) mixing said filtered material with additional sodium silicate and sodium hydroxide; and (d) maintaining this mixture under crystalline growth conditions for sufficient time to form crystalline zeolites.
5. A process, as defined in Claim 1, the further steps of:
(a) bubbling an oxygen-containing gas through said waste water to convert any divalent iron salt to the tri-valent state.
(a) bubbling an oxygen-containing gas through said waste water to convert any divalent iron salt to the tri-valent state.
6. A process, as defined in Claim 4, the improvement wherein the sodium aluminate solution contains small quanti-ties of colloidal silicic acid to accelerate zeolite forma-tion.
7. A process, as defined in Claim 1, in which the acidic waste waters have the following average analysis:
Al3+ 12-16 g/liter Fe3+ 4-6 g/liter Ca2+ 2-4 g/liter Mg2+ 2-4 g/liter SiO2 0.2-0.4 g/liter Cl- 65-90 g/liter Free HCl 4-6 g/liter
Al3+ 12-16 g/liter Fe3+ 4-6 g/liter Ca2+ 2-4 g/liter Mg2+ 2-4 g/liter SiO2 0.2-0.4 g/liter Cl- 65-90 g/liter Free HCl 4-6 g/liter
8. A process, as defined in Claim 1, the improvement of adjusting the pH of the acidic waste waters in step A by the addition of an alkaline earth precipitating agent to the range of about 3-8.
9. A process, as defined in Claim 1, in which the pH value is adjusted by the addition of an alkaline precipitating agent to a range of about 6.6-6.7.
10. A process, as defined in Claim 1, in which the waste waters contain sulfuric acid, the step of adding the oxide or hydrox-ide of calcium to said waste waters so as to react said sulfuric acid to form insoluble calcium sulfate and thereafter filtering off the insoluble precipitate.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3213932.2 | 1982-04-15 | ||
| DE19823213932 DE3213932A1 (en) | 1982-04-15 | 1982-04-15 | METHOD FOR THE TREATMENT OF ALUMINUM AND IRONIC ACIDS |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1201422A true CA1201422A (en) | 1986-03-04 |
Family
ID=6161003
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000425803A Expired CA1201422A (en) | 1982-04-15 | 1983-04-13 | Process for the recovery of aluminum and iron salts from acidic waste waters |
Country Status (9)
| Country | Link |
|---|---|
| EP (1) | EP0092108B1 (en) |
| JP (1) | JPS58181722A (en) |
| AT (1) | ATE29869T1 (en) |
| CA (1) | CA1201422A (en) |
| DE (2) | DE3213932A1 (en) |
| DK (1) | DK166883A (en) |
| NO (1) | NO831323L (en) |
| NZ (1) | NZ203890A (en) |
| ZA (1) | ZA832667B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101830477A (en) * | 2010-06-10 | 2010-09-15 | 济宁医学院 | Technology for preparing PSAF (Polymer Silica Aluminum Ferrum) by waste rock base raw material and PSAF flocculant prepared by same |
| WO2019232149A1 (en) | 2018-05-30 | 2019-12-05 | Lixivia, Inc. | Selective extraction of metals from complex inorganic sources |
Families Citing this family (11)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4306663A1 (en) * | 1993-03-03 | 1994-09-08 | Sued Chemie Ag | Process for the environmentally friendly utilization of acid wastewater |
| DE10324561A1 (en) * | 2003-05-30 | 2004-12-16 | Süd-Chemie AG | Semi-synthetic bleaching earth |
| WO2005095674A1 (en) * | 2004-03-31 | 2005-10-13 | G.R. Trattamenti Termici - Grtt S.R.L. | Process for recovering caustic soda solutions from pickling of aluminum extrusion matrix |
| DE102004027619B4 (en) * | 2004-06-05 | 2008-04-03 | Hottinger Baldwin Messtechnik Gmbh | Overload protection for a force measuring element |
| AU2012262586B2 (en) * | 2011-06-03 | 2015-05-14 | Aem Technologies Inc. | Methods for preparing hematite |
| DE102012108298B4 (en) * | 2012-05-23 | 2015-05-21 | Envirochemie Gmbh | Removal of aluminum from wash liquor |
| CN102718267B (en) * | 2012-07-18 | 2013-11-20 | 广西大学 | Method for preparing black iron oxide by utilizing yellow ammonium iron alum slag |
| CN103253797B (en) * | 2013-06-04 | 2015-06-03 | 苏州南风优联环保工程有限公司 | Online treatment and recycling technique for waste water on anode oxidization production line |
| CN103788708A (en) * | 2014-02-12 | 2014-05-14 | 铜陵瑞莱科技有限公司 | Chitosan-containing iron oxide green pigment |
| CN109455748A (en) * | 2018-12-17 | 2019-03-12 | 北京建工金源环保发展股份有限公司 | A method of recycling aluminum nitrate from waste acid liquor |
| CN112551535A (en) * | 2020-12-30 | 2021-03-26 | 泉州市利芝新材料科技有限公司 | Spodumene iron-removing and whitening process |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1517727A1 (en) * | 1963-03-31 | 1969-04-24 | Baer Dr Erhardt | Process for cleaning up industrial waste water |
| US3425800A (en) * | 1967-10-05 | 1969-02-04 | Aluminum Co Of America | Production of crystalline zeolites |
| GB1218601A (en) * | 1968-01-01 | 1971-01-06 | Unifloc Ltd | Disposal of waste liquors from pickling processes |
| US3494864A (en) * | 1969-06-16 | 1970-02-10 | Robert A Willihnganz | Water purification process |
| US3798160A (en) * | 1971-03-29 | 1974-03-19 | American Metal Climax Inc | Treatment of aluminum waste liquors |
| GB1454933A (en) * | 1974-10-12 | 1976-11-10 | Tioxide Group Ltd | Process for the treatment of acidic waste liquid containing dissolved salts |
| JPS5221197A (en) * | 1975-08-07 | 1977-02-17 | Nitto Electric Ind Co | Method of collecting laver spores |
-
1982
- 1982-04-15 DE DE19823213932 patent/DE3213932A1/en not_active Withdrawn
-
1983
- 1983-03-29 JP JP58051698A patent/JPS58181722A/en active Pending
- 1983-04-06 EP EP83103362A patent/EP0092108B1/en not_active Expired
- 1983-04-06 AT AT83103362T patent/ATE29869T1/en not_active IP Right Cessation
- 1983-04-06 DE DE8383103362T patent/DE3373806D1/en not_active Expired
- 1983-04-13 CA CA000425803A patent/CA1201422A/en not_active Expired
- 1983-04-14 NZ NZ203890A patent/NZ203890A/en unknown
- 1983-04-14 NO NO831323A patent/NO831323L/en unknown
- 1983-04-15 DK DK166883A patent/DK166883A/en not_active IP Right Cessation
- 1983-04-15 ZA ZA832667A patent/ZA832667B/en unknown
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101830477A (en) * | 2010-06-10 | 2010-09-15 | 济宁医学院 | Technology for preparing PSAF (Polymer Silica Aluminum Ferrum) by waste rock base raw material and PSAF flocculant prepared by same |
| WO2019232149A1 (en) | 2018-05-30 | 2019-12-05 | Lixivia, Inc. | Selective extraction of metals from complex inorganic sources |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3373806D1 (en) | 1987-10-29 |
| DK166883A (en) | 1983-10-16 |
| EP0092108A3 (en) | 1985-05-22 |
| EP0092108B1 (en) | 1987-09-23 |
| NZ203890A (en) | 1986-07-11 |
| ZA832667B (en) | 1983-12-28 |
| JPS58181722A (en) | 1983-10-24 |
| NO831323L (en) | 1983-10-17 |
| DK166883D0 (en) | 1983-04-15 |
| EP0092108A2 (en) | 1983-10-26 |
| DE3213932A1 (en) | 1983-10-27 |
| ATE29869T1 (en) | 1987-10-15 |
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