CN1292981C - Process of preparing sodium sulfide from reducing sodium thiosulfate by microwave inducting carbon - Google Patents
Process of preparing sodium sulfide from reducing sodium thiosulfate by microwave inducting carbon Download PDFInfo
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- CN1292981C CN1292981C CNB2004100394936A CN200410039493A CN1292981C CN 1292981 C CN1292981 C CN 1292981C CN B2004100394936 A CNB2004100394936 A CN B2004100394936A CN 200410039493 A CN200410039493 A CN 200410039493A CN 1292981 C CN1292981 C CN 1292981C
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- carbon
- sodium
- sodium thiosulfate
- microwave
- sodium sulfide
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- AKHNMLFCWUSKQB-UHFFFAOYSA-L sodium thiosulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=S AKHNMLFCWUSKQB-UHFFFAOYSA-L 0.000 title claims abstract description 47
- 235000019345 sodium thiosulphate Nutrition 0.000 title claims abstract description 47
- GRVFOGOEDUUMBP-UHFFFAOYSA-N sodium sulfide (anhydrous) Chemical compound [Na+].[Na+].[S-2] GRVFOGOEDUUMBP-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 229910052979 sodium sulfide Inorganic materials 0.000 title claims abstract description 42
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 title claims abstract description 41
- 229910052799 carbon Inorganic materials 0.000 title claims abstract description 40
- 238000000034 method Methods 0.000 title claims abstract description 30
- 230000008569 process Effects 0.000 title description 9
- 238000006243 chemical reaction Methods 0.000 claims abstract description 9
- 239000007787 solid Substances 0.000 claims abstract description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 6
- 230000009471 action Effects 0.000 claims abstract description 5
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 18
- 239000003610 charcoal Substances 0.000 claims description 10
- 239000000203 mixture Substances 0.000 claims description 9
- 239000000843 powder Substances 0.000 claims description 9
- 239000000571 coke Substances 0.000 claims description 6
- 239000012452 mother liquor Substances 0.000 claims description 5
- CDBYLPFSWZWCQE-UHFFFAOYSA-L sodium carbonate Substances [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 4
- 239000003245 coal Substances 0.000 claims description 3
- 238000001816 cooling Methods 0.000 claims description 3
- 239000000706 filtrate Substances 0.000 claims description 3
- 239000008247 solid mixture Substances 0.000 claims description 3
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 2
- 238000004090 dissolution Methods 0.000 claims 1
- 239000007788 liquid Substances 0.000 abstract description 12
- 239000002699 waste material Substances 0.000 abstract description 11
- 230000009467 reduction Effects 0.000 abstract description 10
- 239000003513 alkali Substances 0.000 abstract description 6
- 239000012535 impurity Substances 0.000 abstract description 3
- 238000005507 spraying Methods 0.000 abstract description 2
- 238000006722 reduction reaction Methods 0.000 description 14
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 11
- 238000004519 manufacturing process Methods 0.000 description 11
- 229910052938 sodium sulfate Inorganic materials 0.000 description 11
- 235000011152 sodium sulphate Nutrition 0.000 description 11
- GEYOCULIXLDCMW-UHFFFAOYSA-N 1,2-phenylenediamine Chemical compound NC1=CC=CC=C1N GEYOCULIXLDCMW-UHFFFAOYSA-N 0.000 description 8
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical compound [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 150000002828 nitro derivatives Chemical class 0.000 description 5
- 238000004064 recycling Methods 0.000 description 5
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 4
- 239000003638 chemical reducing agent Substances 0.000 description 4
- 238000003912 environmental pollution Methods 0.000 description 4
- 239000000047 product Substances 0.000 description 4
- 229910052717 sulfur Inorganic materials 0.000 description 4
- 239000011593 sulfur Substances 0.000 description 4
- -1 aromatic nitro compounds Chemical class 0.000 description 3
- 239000000463 material Substances 0.000 description 3
- 238000002156 mixing Methods 0.000 description 3
- 238000011084 recovery Methods 0.000 description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N sulfuric acid group Chemical class S(O)(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 description 3
- RWSOTUBLDIXVET-UHFFFAOYSA-N Dihydrogen sulfide Chemical compound S RWSOTUBLDIXVET-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 229910002092 carbon dioxide Inorganic materials 0.000 description 2
- 238000010586 diagram Methods 0.000 description 2
- 238000001914 filtration Methods 0.000 description 2
- 229910000037 hydrogen sulfide Inorganic materials 0.000 description 2
- 230000006698 induction Effects 0.000 description 2
- 238000009776 industrial production Methods 0.000 description 2
- 238000006396 nitration reaction Methods 0.000 description 2
- 239000002994 raw material Substances 0.000 description 2
- 230000036632 reaction speed Effects 0.000 description 2
- 238000001694 spray drying Methods 0.000 description 2
- CBCKQZAAMUWICA-UHFFFAOYSA-N 1,4-phenylenediamine Chemical compound NC1=CC=C(N)C=C1 CBCKQZAAMUWICA-UHFFFAOYSA-N 0.000 description 1
- DPJCXCZTLWNFOH-UHFFFAOYSA-N 2-nitroaniline Chemical compound NC1=CC=CC=C1[N+]([O-])=O DPJCXCZTLWNFOH-UHFFFAOYSA-N 0.000 description 1
- XJCVRTZCHMZPBD-UHFFFAOYSA-N 3-nitroaniline Chemical compound NC1=CC=CC([N+]([O-])=O)=C1 XJCVRTZCHMZPBD-UHFFFAOYSA-N 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- 239000004133 Sodium thiosulphate Substances 0.000 description 1
- 239000005864 Sulphur Substances 0.000 description 1
- 239000011358 absorbing material Substances 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- 150000001412 amines Chemical class 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 239000000919 ceramic Substances 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000005265 energy consumption Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 230000008570 general process Effects 0.000 description 1
- VUZPPFZMUPKLLV-UHFFFAOYSA-N methane;hydrate Chemical compound C.O VUZPPFZMUPKLLV-UHFFFAOYSA-N 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 230000001546 nitrifying effect Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- 238000004886 process control Methods 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000011541 reaction mixture Substances 0.000 description 1
- 238000011946 reduction process Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 238000007086 side reaction Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000004083 survival effect Effects 0.000 description 1
- 231100000331 toxic Toxicity 0.000 description 1
- 230000002588 toxic effect Effects 0.000 description 1
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Abstract
The present invention discloses a method for preparing sodium sulfide by sodium thiosulfate reduction induced by microwave, which is characterized in that under the condition that the molar ratio of sodium thiosulfate to alkali is 1 to 2, the sodium thiosulfate, the alkali and excessive carbon are mixed and concentrated or dried by spraying, the obtained solids are under microwave action for 2 to 3 minutes, and the reaction is finished; the solids after being cooled are added with water for dissolving, the carbon which does not react completely is filtered and recovered, and the filter liquid is the solution of sodium sulfide. The present invention can make waste liquid containing sodium thiosulfate economically and rapidly reduced to regenerate the sodium sulfide, and the produced sodium sulfide does not contain organic impurities and can meet the circular requirements.
Description
Technical Field
The invention provides a method for reducing sodium thiosulfate into sodium sulfide by using carbon under the action of microwaves. The method has the advantages of high speed and low energy consumption, and can be widely used for recycling the waste liquid containing the sodium thiosulfate, reducing the production cost and reducing the environmental pollution.
Background
Sodium sulfide is a widely used reducing agent, commonly used for reducing nitro compounds to amine-based compounds, and particularly for reducing aromatic nitro compounds to aromatic amine compounds. Usually by absorption of hydrogen sulfide with a base, or by reduction of sodium sulfate with carbon. The former is not very widely used due to the limitation of the source and purity of hydrogen sulfide; the latter is widely used in industrial production due to the easily available raw materials of sodium sulfate and carbon, low cost and good product quality. As shown in the following formula:
because the sodium sulfide has wide sources, low price, easily controlled reaction conditions and easy product post-treatment, the sodium sulfide is widely used as a reducing agent in the process of producing o-phenylenediamine, p-phenylenediamine, m-nitroaniline and other aromatic amine compounds. Unfortunately, while the nitro compound is being reduced, sodium sulfide is oxidized to sodium thiosulfate, producing sodium hydroxide, as shown in the following formula:
sodium thiosulfate and sodium hydroxide are present in the waste liquid in the form of a solution, which also contains unreacted organic raw materials and dissolved products. The recovery of sodium thiosulfate requires complicated separation and refining processes, and the cost is high. And the emission causes serious environmental pollution. Taking the production of o-phenylenediamine as an example, the current annual production of o-phenylenediamine in China needs more than 2 million tons of sodium sulfide, needs more than 5-6 million tons of sodium sulfide, generates more than 12 million tons of waste liquid of sodium thiosulfate, and causes serious environmental problems due to improper treatment, thereby endangering the survival of o-phenylenediamine production enterprises.
Sodium thiosulfate is unstable at high temperatures and heating produces sulfur and sodium sulfate in addition to the desired sodium sulfide. Reducing sodium sulfate is difficult and requires drastic conditions. In US4865750, during the oxidation of sodium sulphide to recover sulphur using the Stretford process, part of the sodium sulphide is oxidised to sodium thiosulphate, which is inactive to the Stretford process and thus gradually accumulates. When a certain concentration is exceeded, the Stretford process is severely disturbed. US4865750 thus describes a method of spraying sodium thiosulfate in a mixture with carbon into a burning carbon reduction furnace. Controlling the amount of air to combust the carbon part, maintaining the temperature of the furnace at 900-950 ℃ by the generated heat, and reducing the sodium thiosulfate and the generated sodium sulfate into sodium sulfide. The carbon in the process has two functions, part being burned for heating and part being a reductant. Therefore, the amount of the supplied air must be strictly controlled, and when the amount of the supplied air is too large, carbon is excessively burned, carbon consumption is excessively large, and when the amount of the supplied air is too small, the temperature is insufficient, and the reduction reaction cannot occur, so that the process control is difficult. In addition, the reaction speed is slow, the equipment investment is large, the cost is high, the production efficiency is low, and the industrial production is not facilitated. Therefore, an economical and rapid method is found, the sodium thiosulfate waste liquid is converted into sodium sulfide for recycling, the production cost of o-phenylenediamine can be reduced, the environmental pollution is thoroughly eliminated, the clean production of o-phenylenediamine is realized, and the method not only has economic value, but also has very important social significance.
Disclosure of Invention
The invention provides a method for reducing sodium thiosulfate waste liquid by microwave-induced carbothermic reduction. The waste liquid containing the sodium thiosulfate can be economically and rapidly reduced to regenerate the sodium sulfide, and the generated sodium sulfide does not contain organic impurities and can meet the requirement of recycling.
The principle of the invention is as follows: carbon is a very good microwave absorbing material and can reach a temperature of over 1000 ℃ within 45-60 seconds. Under the condition, sodium thiosulfate can be quickly reduced into sodium sulfide, and organic impurities in the sodium sulfide are decomposed into carbon dioxide and water at high temperature, so that the reduction and purification are simultaneously completed, and high-quality sodium sulfide is obtained for recycling.
From the above formula, in order to control the occurrence of side reactions, the required molar ratio of sodium thiosulfate to base is 1: 2, under which conditions carbon can reduce sodium thiosulfate to sodium sulfide without producing sulfur. CO and CO2 are produced. The alkali can be sodium hydroxide or sodium carbonate. While reducing the nitro compound mother liquor with sodium sulfide. The molar ratio of sodium thiosulfate to sodium hydroxide is exactly 1: 2. Therefore, the alkali is not needed to be added, and the materials in the alkali can be fully utilized. The general process comprises the steps of mixing the reducing mother liquor with excessive carbon, concentrating or spray drying, reacting the obtained solid for 2-3 minutes under the action of microwaves, cooling, adding water for dissolving, filtering and recovering carbon which is not completely reacted, wherein the filtrate is a solution of sodium sulfide and can be directly used for reducing nitro compounds.
The carbon used as the reducing agent may be coal, charcoal, coke, etc., with charcoal and coke being preferred. In order to increase the surface area, the carbon is crushed into 100-200 mesh powder, and the addition amount is 20-50% of the weight of the sodium thiosulfate, preferably 30-40%. Too little reduction is incomplete, while too much does not affect the recovery, but only increases the recovery workload, and the carbon and the mother liquor need to be uniformly mixed so as to make the composition in the concentrated solid mixture uniform.
More specifically: a method for preparing sodium sulfide by reducing sodium thiosulfate through microwave-induced carbon comprises the steps of mixing the sodium thiosulfate and excessive carbon under the condition that the molar ratio of the sodium thiosulfate to alkali is 1: 2, concentrating or spray drying, reacting obtained solids for 2-3 minutes under the action of microwaves,cooling, adding water to dissolve the solids, filtering and recovering carbon which is not completely reacted, wherein filtrate is a solution of the sodium sulfide. The carbon is coal, charcoal or coke. The carbon is preferably charcoal and coke. The carbon is powder which is crushed into 100-200 meshes and is added in an amount of 20-50% of the weight of the sodium thiosulfate. The amount of said char added is preferably 30-40% by weight of the sodium thiosulfate. The carbon and sodium thiosulfate mother liquor are mixed uniformly to make the composition uniform in the concentrated solid mixture. The microwave oven adopts a microwave oven or a microwave generator with certain power, the input power of the general microwave oven is 1000W-30 KW, the frequency is 2450MHz, and the power is determined by the treatment capacity. The treatment may be continuous or intermittent, depending on the manner of introduction of the microwaves. The reactor is made of a high temperature resistant material such as ceramic which does not absorb microwaves. In the embodiment, a household microwave oven with power of 1000W and frequency of 2450MHz is adopted, and the reactor is an alumina crucible, but the invention is not limited to the above.
Because the traditional heating mode is heating from outside to inside, carbon can react with generated CO at high temperature2The reaction is a strong endothermic reaction, so that the internal temperature of the material is lower than the external temperature, a cold center phenomenon occurs, the reduction process takes too long, and the complete reaction can be realized generally within about 3 hours. The microwave-induced carbon thermal reduction has high heating speed, uniform internal and external temperature and greatly increased reaction speed, and can completely react in about 2 minutes. Because the reduction speed is high, the chance of generating sodium sulfate by decomposing sodium thiosulfate is reduced, and the reduction reaction is easier to carry out. And simultaneously, under the induction of microwave, sodium sulfate can be completely reduced into sodium sulfide within 2-3 minutes, so that the method not only can be used for reducing sodium thiosulfate into sodium sulfide, but also can be used for reducing sodium thiosulfate containing sodium sulfate into sodium sulfide, and the production of sodium sulfide is more efficient and the cost is lower.
The method of the present invention has wide application range due to small equipment investment, high operation efficiency and low operation cost. The method not only can be used for recycling all waste liquid containing sodium thiosulfate, but also can be used for treating waste acid generated by nitration reaction. It is known that nitration with a mixture of nitric and sulfuric acids produces a large amount of spent acid liquor containing a large amount of sulfuric acid, a small amount of nitric acid and toxic nitro compounds. How to treat the waste liquid at low cost is the subject of all nitrifying enterprises, and the invention provides a very effective method. Not only can eliminate environmental pollution, but also can obtain useful sodium sulfide products.
Drawings
FIG. 1 is a process flow diagram of a process for preparing sodium sulfide by microwave-induced carbon reduction of sodium thiosulfate according to the present invention;
FIG. 2 is a process flow diagram of a process for preparing sodium sulfide by microwave-induced carbon reduction of sodium thiosulfate according to the present invention;
in the figure: 1. mixing kettle 2, pump 3, drying tower
4. Microwave oven 5, conveyor belt 6, dissolving kettle
7. Filter 8, storage tank
Detailed Description
Example i: 50g of sodium thiosulfate and 20g of charcoal powder are uniformly mixed, placed in a crucible and covered, and only air holes are left to prevent the mixture from being burnt in contact with air. The mixture is put into a microwave oven with input power of 1000W and microwave frequency of 2450MHz, and the microwave cavity is heated for 3 minutes under induction, and sulfur is generated besides sodium sulfide. The conversion of sodium thiosulfate was greater than 95% with a small amount of sodium sulfate remaining.
Example 2: 50g of sodium thiosulfate, 25g of sodium hydroxide and 20g of charcoal powder are uniformly mixed, put into a crucible, put into a 1000W 2450MHz microwave oven, heated for 3 minutes and subjected to reduction reaction to complete the reduction reaction. The conversion of sodium thiosulfate was greater than 98%, and no sulfur and sodium sulfate were present. The reaction mixture was dissolved in 100ml of water and filtered to remove excess carbon to give a yellowish transparent liquid with a sodium sulfide content of 32%.
Example 3: 50g of sodium sulfate and 20g of charcoal powder are mixed uniformly, put into a crucible, put into a microwave oven with 1000W and 2450MHz, heated for 5 minutes, and the reduction reaction is finished. The conversion rate of the sodium thiosulfate is more than 96 percent, and the sodium sulfide is processed by the method of example 2 to obtain almost colorless and transparent sodium sulfide with the content of 15 percent.
Example 4: 200ml of waste liquid from the production of o-phenylenediamine and 20g of charcoal powder are mixed and concentrated to dryness, the mixture is taken out and put into a crucible, the crucible is placed into a 1000W 2450MHz microwave oven to be heatedfor 3 minutes, and the mixture is taken out and treated according to the method in the example 2. The sodium sulfide solution obtained was yellowish and contained 30%. Can be completely recycled for reducing o-nitroaniline to produce o-phenylenediamine.
Claims (6)
1. A method for preparing sodium sulfide by reducing sodium thiosulfate through carbon induced by microwave is characterized in that under the condition that the molar ratio of sodium thiosulfate to sodium hydroxide or sodium carbonate is 1: 2, the sodium sulfide and carbon are mixed, the carbon is crushed into powder with the size of 100 meshes and the addition amount of the powder is 20-50% of the weight of the sodium thiosulfate, the powder is concentrated or spray-dried, the obtained solid is reacted for 2-3 minutes under the action of microwave, the reaction is finished, water is added for dissolution after cooling, carbon which is not completely reacted is filtered and recovered, and the filtrate is a solution of the sodium sulfide.
2. The method of claim 1, wherein the carbon is coal, charcoal or coke.
3. The method of claim 2, wherein the carbon is charcoal or coke.
4. The method of claim 1, wherein the carbon is added in an amount of 30-40% by weight of the sodium thiosulfate.
5. The method of claim 1, wherein the carbon and the sodium thiosulfate mother liquor are uniformly mixed to make the composition of the concentrated solid mixture uniform.
6. The method for preparing sodium sulfide by reducing sodium thiosulfate through carbon induced by microwaves according to claim 1, wherein the microwave oven is a microwave oven with input power of 1000W-30 KW and microwave frequency of 2450MHz, and the reactor is a high-temperature-resistant reactor which does not absorb microwaves.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CNB2004100394936A CN1292981C (en) | 2004-02-17 | 2004-02-17 | Process of preparing sodium sulfide from reducing sodium thiosulfate by microwave inducting carbon |
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| Application Number | Priority Date | Filing Date | Title |
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| CNB2004100394936A CN1292981C (en) | 2004-02-17 | 2004-02-17 | Process of preparing sodium sulfide from reducing sodium thiosulfate by microwave inducting carbon |
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| CN1292981C true CN1292981C (en) | 2007-01-03 |
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| CNB2004100394936A Expired - Lifetime CN1292981C (en) | 2004-02-17 | 2004-02-17 | Process of preparing sodium sulfide from reducing sodium thiosulfate by microwave inducting carbon |
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Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101948100B (en) * | 2010-10-08 | 2011-08-10 | 赵志军 | Clean method for producing anhydrous sodium sulfide |
| CN105001097A (en) * | 2015-06-11 | 2015-10-28 | 安徽东至广信农化有限公司 | O-phenylenediamine mother solution deaminizing and ammonia gas removal method |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4865750A (en) * | 1986-05-02 | 1989-09-12 | Engineered Systems International, Inc. | Methods for reducing anions in process chemicals |
| CN1075299A (en) * | 1992-12-06 | 1993-08-18 | 新疆天山化工厂 | Process for purifying of sodium sulfide |
-
2004
- 2004-02-17 CN CNB2004100394936A patent/CN1292981C/en not_active Expired - Lifetime
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4865750A (en) * | 1986-05-02 | 1989-09-12 | Engineered Systems International, Inc. | Methods for reducing anions in process chemicals |
| CN1075299A (en) * | 1992-12-06 | 1993-08-18 | 新疆天山化工厂 | Process for purifying of sodium sulfide |
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