WO2004083123A1 - Procede d'obtention de chromates de metal alcalin - Google Patents
Procede d'obtention de chromates de metal alcalin Download PDFInfo
- Publication number
- WO2004083123A1 WO2004083123A1 PCT/CN2003/000199 CN0300199W WO2004083123A1 WO 2004083123 A1 WO2004083123 A1 WO 2004083123A1 CN 0300199 W CN0300199 W CN 0300199W WO 2004083123 A1 WO2004083123 A1 WO 2004083123A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- chromate
- alkali metal
- potassium
- product
- metal hydroxide
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
- C01G37/00—Compounds of chromium
- C01G37/14—Chromates; Bichromates
Definitions
- the invention relates to a method for producing chromate, in particular to a method for producing alkali metal chromate. As in J53 ⁇ 4
- Chromate is a very important chemical raw material.
- a raw material for the preparation of complex series of chemical products such as dichromate, chromium oxide and chromic anhydride, it is mainly used for tanning, pigments, dyes, metallurgy, materials, enamels, metals and Anti-corrosion and medicine.
- Chromite production from chromite is an important basic raw material industry at the intersection of chemical industry and metallurgy.
- the current industrial production method of chromate is mainly the alkali metal carbonate roasting method.
- the chromite, alkali metal carbonate and air are subjected to a high-temperature oxidation roasting reaction in a rotary kiln.
- the reaction temperature is 900-120 (TC, reaction process
- alkaline auxiliary materials such as lime, dolomite or iron oxide, etc.
- the production of chromate by roasting produces a large amount of highly toxic chromium-containing waste residues, causing severe environmental pollution, which is a world environmental problem that has not been solved so far.
- the amount of calcium auxiliary materials is twice the amount of chromium ore
- the reaction temperature is as high as 1200 ° C
- the chromium recovery rate is less than 80%
- 2.5 to 3.0 tons of highly toxic chromium are required to be produced per ton of chromium salt products.
- Slag The current disposal of chromium slag is mainly landfilling, which not only wastes chromium resources and calcium excipients, but also has major environmental safety risks.
- the calcium-free roasting method which is the most advanced roasting technology at present, has a higher yield of chromium and less emissions of chromium slag compared with the calcium roasting method, but the total chromium yield of the calcium-free roasting method is 90%. /. Moreover, 0.8 tons of chromium-containing waste residues need to be emitted for each ton of production, and the problem of chromium residue pollution has still not been completely solved.
- the purpose of the present invention is to overcome the defects of serious environmental pollution, low utilization rate of chromium ore resources and high reaction temperature in the existing chromate production methods, so as to provide a chromate with industrial operability without the need to add auxiliary materials. production method.
- the production method of chromate provided by the present invention is based on the principle that heterogeneous reaction between erbium ore in an alkali metal hydroxide melt or aqueous solution at 200-550 ° C and oxidant, and trivalent chromium in chromite are Oxidation to hexavalent chromium produces alkali metal chromate.
- the reaction formula using oxygen as an oxidant is as follows ⁇
- Me represents an alkali metal and is sodium or potassium.
- the object of the present invention is achieved by the following technical scheme:
- the method for producing a chromate provided by the present invention is characterized in that the iron ore is oxidized and decomposed with an oxidant in an alkali metal hydroxide melt or an aqueous solution, and an aqueous solution is used.
- the reaction product is leached to obtain an leaching slurry, and the crude chromate product is separated from the leaching slurry.
- the method includes the following steps:
- chromite is reacted with an oxidant in a reactor in an alkali metal hydroxide melt or an aqueous solution to obtain a mixed product containing an alkali metal hydroxide, an alkali metal chromate and iron slag;
- the weight of the alkali metal hydroxide is 2-8 times the weight of chromite; the amount of oxidant is equal to or exceeds the chemical reaction metering amount required for the decomposition of chromite;
- the water content of the reaction system is 0- 50wt% ; reaction temperature is 200-550 ° C; reaction time is 1-20 hours;
- step 2) leaching the mixed product obtained in step 1) with a 0-30 wt% alkali metal hydroxide aqueous solution to obtain a slurry containing 30-7 (kt% alkali metal hydroxide;
- step 2) The leaching slurry obtained in step 2) is separated to obtain crude alkali metal chromate product, iron slag and lye.
- the method for producing chromate provided by the present invention further includes the step of purifying the chromate crude product to obtain pure chromate crystals, and the steps are as follows ⁇
- the pure chromate solution is heated and evaporated, crystallized, filtered, and dried to obtain a pure chromate crystal product and a crystallization mother liquor.
- the oxidant in step 1) includes air, oxygen, sodium nitrate, potassium nitrate, sodium peroxide, potassium peroxide or a mixture thereof.
- the alkali metal hydroxide in the step 1) includes the alkali metal hydroxide returned from the step 3), an additional alkali metal hydroxide or a mixture thereof.
- the alkali metal hydroxide in step 1) and step 2) is sodium hydroxide or potassium hydroxide.
- the alkali solution including step 3) is returned to step 1) as an alkali metal hydroxide aqueous solution for decomposing chromite.
- the aqueous solution in step 4) is a 0-20 wt% sodium hydroxide or potassium hydroxide aqueous solution.
- the acidifying agent is inorganic acid, acid gas, chromic anhydride, sodium dichromate, potassium dichromate, sodium bicarbonate, potassium bicarbonate, sodium bisulfate or potassium bisulfate, etc .; the inorganic acid Including sulfuric acid, hydrochloric acid or nitric acid; the acid gas is carbon dioxide or sulfur dioxide.
- the crystallization mother liquor including step 6) is returned to step 4) and used as an aqueous solution for dissolving the crude chromate product.
- the advantages of the chromate production method provided by the present invention are:
- the reaction temperature is 200-550 ° C, which is about 700 ° C lower than the existing roasting method, which can greatly reduce energy consumption, and has mild reaction conditions and strong industrial operability;
- the chromium content of the iron slag in the chromate production method provided by the present invention is reduced to 0.5%, and the chromium recovery rate is close to 100%, which is 10-20% higher than the existing industrial method, thereby improving the use of chromium ore resources Rate
- the crude chromate product obtained in the chromate production method provided by the present invention can be purified to obtain pure chromate crystals. Both the crude chromate product and the pure chromate crystals can be used for the production of other chromium compounds.
- the chromate production method provided by the present invention does not add any auxiliary materials, and reduces the amount of slag from the source.
- the amount of iron slag produced is 0.6 tons per ton of product, and the slag discharge is only 1 with the calcium roasting method. / 4, and no dust exhaust gas, thereby reducing environmental pollution;
- the iron slag obtained by the present invention is basically free of chromium. It is a uniform powder enriched with iron and magnesium only. Iron-based raw materials in the iron and steel or cement industry, eliminating the problem of iron slag disposal and environmental pollution caused by iron slag;
- the alkali metal hydroxide used for decomposing chromite according to the present invention is recycled after being separated, which greatly reduces the chemical consumption of alkali raw materials and reduces the cost of raw materials.
- FIG. 1 Schematic diagram of the process flow of the present invention. Specific implementation plan
- chromite with a particle size of less than 200 mesh in the reactor, and the potassium hydroxide and the potassium hydroxide solution that removes part of the water are returned to the reactor.
- the weight ratio of total potassium hydroxide to chromite is 4: 1. After the air is mixed in, the mixture is heated to 300 ° C and reacted for 10 hours to obtain a mixed product containing lye, potassium chromate and iron slag.
- the chromium conversion in chromite is greater than 99%.
- the mixed product was leached with a 30% by weight potassium hydroxide aqueous solution, and the alkali concentration of the leaching slurry was 60% by weight.
- the leaching slurry was filtered to separate the crude potassium chromate product, iron slag, and lye. 055wt% ⁇ After the iron slag was washed and dried, the chromium content of the iron slag was 0.0555% by analysis.
- the mixed product was leached with a 30 wt% sodium hydroxide aqueous solution, and the alkali concentration of the leaching slurry was 45 wt%.
- the leaching slurry was filtered to separate the crude sodium chromate product, iron slag, and lye. 15wt ° / ⁇ After the iron slag was washed and dried, the iron content of the iron slag was measured to be 0.15 wt ° /. .
- Chromite with a particle size of less than 200 mesh is added to the reactor. Potassium hydroxide and potassium hydroxide solution removed from the circulation are returned to the reactor.
- the weight ratio of total potassium hydroxide to iron ore is 2: 1. After introducing oxygen and full mixing, heat up to 350 ° C and react for 6 hours to obtain a mixed product containing lye, potassium chromate and iron slag.
- the chromium conversion in chromite is greater than 99%.
- the mixed product was leached with a 20% by weight potassium hydroxide aqueous solution, and the alkali concentration of the leaching paddle was 40% by weight.
- the leaching slurry was filtered to separate the crude potassium chromate product, iron slag, and lye. 2wt% ⁇ After the iron slag was washed and dried, the chromium content of the iron slag was measured to be 0.2 wt%.
- the mixed product was leached with water, and the alkali concentration of the leaching slurry was 45 wt%.
- the leaching slurry was filtered to separate the crude potassium chromate product, iron slag, and lye. Lwt% ⁇ After washing and drying the iron slag, the iron content of the iron slag was analyzed and determined to be 0.1 wt%.
- Chromite with a particle size of less than 200 mesh is added to the reactor. Equal moles of sodium peroxide, sodium hydroxide and chromite are recycled to the reactor to return the sodium hydroxide solution to the reactor. The weight ratio of the amount to the chromite is 8: 1. After the mixture is completely mixed, the temperature is raised to 300'C, and the reaction is performed for 20 hours to obtain a mixed product containing an lye, sodium chromate and iron slag.
- the mixed product was leached with a 25 wt% sodium hydroxide aqueous solution, and the alkali concentration of the leaching slurry was 35 wt%.
- the leaching slurry was filtered to separate the crude sodium chromate product, iron slag and lye. 3wt% ⁇ After the iron slag was washed and dried, the analytical measurement of the chromium content of the iron slag was 0.3 wt%.
- chromite with a particle size of less than 200 mesh, potassium hydroxide and potassium hydroxide solution that is recycled back to the reactor after complete dehydration.
- the weight ratio of total potassium hydroxide to chromite is 7: 1
- the chromium conversion in chromite is greater than 99%.
- the mixed product was leached with a 10 wt% potassium hydroxide aqueous solution, and the alkali concentration of the leaching slurry was 35 wt%.
- the leaching slurry was filtered to separate the crude potassium chromate product, iron slag, and lye. 05wt% ⁇ After the iron slag was washed and dried, the chromium content of the iron slag was measured to be 0.05wt%.
- the mixed product was leached with a washing solution containing about 5wt% of iron slag, and the alkali concentration of the leaching slurry was 70wt%.
- the leaching slurry was filtered to separate the crude potassium chromate product, iron slag, and lye. 4wt% ⁇ After the iron slag was washed and dried, the chromium content of the iron slag was measured to be 0.4 wt%.
- the mixed product was leached with a 15% by weight sodium hydroxide aqueous solution, and the alkali concentration of the leaching slurry was 50% by weight.
- the leaching slurry was filtered to separate the crude sodium chromate product, iron slag, and lye. Lwt% ⁇ After the iron slag was washed and dried, the chromium content of the iron slag was 0. lwt%.
- the mixed product was leached with a 10% by weight sodium hydroxide aqueous solution, and the alkali concentration of the leaching slurry was 0% by weight.
- the leaching slurry was filtered to separate the crude sodium chromate product, iron slag, and lye. 2wt% ⁇ After the iron slag was washed and dried, the chromium content of the iron slag was measured to be 0.2 wt%.
- the mixed product was leached with a potassium hydroxide aqueous solution having a concentration of 15 rt%, and the alkali concentration of the leaching slurry was 30 wt%.
- the leaching slurry was filtered to separate the crude potassium chromate product, iron slag, and lye. 04rt% ⁇ After the iron slag was washed and dried, the chromium content of the iron slag was 0.04rt%.
- chromite with a particle size of less than 200 mesh, potassium hydroxide and potassium hydroxide solution that is recycled back to the reactor after complete dehydration.
- the weight ratio of total potassium hydroxide to chromite is 4: 1. After the air is mixed in, the temperature is raised to 550 ° C, and the reaction is performed for 3 hours to obtain a mixed product containing lye, potassium chromate and iron slag.
- the chromium conversion in chromite is greater than 99%.
- the mixed product was leached with a 25 wt% potassium hydroxide aqueous solution, and the alkali concentration of the leaching slurry was 55 wt%.
- the leaching slurry was filtered to separate the crude potassium chromate product, iron slag, and lye. 035wt% ⁇ After the iron slag was washed and dried, the chromium content of the iron slag was 0.0355% by analysis.
- Chromite with a particle size of less than 200 mesh is added to the reactor. Equal moles of potassium peroxide, potassium hydroxide and chromite are recycled to the reactor to return the potassium hydroxide solution to the reactor. The weight ratio of the amount to the chromite is 8: 1. After the mixture is completely mixed, the temperature is raised to 200 ° C, and the reaction is performed for 20 hours to obtain a mixed product containing an lye, potassium chromate and iron slag.
- the mixed product was leached with water, and the alkali concentration of the leaching slurry was 50 wt%.
- the leaching slurry was filtered to separate the crude potassium chromate product, iron slag, and lye. 5wt% ⁇ After the iron slag was washed and dried, the chromium content of the iron slag was measured to be 0.5 wt%.
- the purified potassium chromate solution is evaporated, crystallized, and filtered. , Dry to obtain bell chromate crystals, the purity of potassium chromate crystals is 99.8%, which meets the requirements of qualified products.
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Manufacture And Refinement Of Metals (AREA)
Description
Claims
Priority Applications (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AU2003227163A AU2003227163A1 (en) | 2003-03-19 | 2003-03-19 | Method for production of alkali metal chromates |
US10/549,594 US7968066B2 (en) | 2003-03-19 | 2003-03-19 | Method for production of alkali metal chromates |
PCT/CN2003/000199 WO2004083123A1 (fr) | 2003-03-19 | 2003-03-19 | Procede d'obtention de chromates de metal alcalin |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
PCT/CN2003/000199 WO2004083123A1 (fr) | 2003-03-19 | 2003-03-19 | Procede d'obtention de chromates de metal alcalin |
Publications (1)
Publication Number | Publication Date |
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WO2004083123A1 true WO2004083123A1 (fr) | 2004-09-30 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/CN2003/000199 WO2004083123A1 (fr) | 2003-03-19 | 2003-03-19 | Procede d'obtention de chromates de metal alcalin |
Country Status (3)
Country | Link |
---|---|
US (1) | US7968066B2 (zh) |
AU (1) | AU2003227163A1 (zh) |
WO (1) | WO2004083123A1 (zh) |
Cited By (8)
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CN101817561A (zh) * | 2010-04-12 | 2010-09-01 | 中国科学院过程工程研究所 | 一种铬铁矿加压浸出清洁生产铬酸钠的方法 |
CN101844810A (zh) * | 2010-04-29 | 2010-09-29 | 中国科学院过程工程研究所 | 一种由铬酸钾生产铬酸钠的方法 |
CN102020317A (zh) * | 2010-12-27 | 2011-04-20 | 中国科学院过程工程研究所 | 一种以铬酸钡为中间体由铬酸钾制备重铬酸钠的方法 |
CN102320661A (zh) * | 2011-09-06 | 2012-01-18 | 重庆民丰化工有限责任公司 | 三相催化氧化制备可溶性铬酸盐的工艺 |
CN104195346A (zh) * | 2014-09-15 | 2014-12-10 | 中国科学院过程工程研究所 | 一种高效提取提钒尾渣中铬的清洁工艺方法 |
CN104341004A (zh) * | 2013-07-25 | 2015-02-11 | 中国科学院过程工程研究所 | 一种铬铁矿加压浸出制备铬酸钾的新工艺 |
CN109957661A (zh) * | 2019-04-29 | 2019-07-02 | 中南大学 | 一种微波强化从镍铁冶炼渣中回收铬并制备轻质隔热材料的方法 |
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JPS5246200B2 (zh) * | 1972-11-11 | 1977-11-22 | Nippon Chemical Ind | |
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DE2607131C2 (de) * | 1976-02-21 | 1983-11-24 | Bayer Ag, 5090 Leverkusen | Verfahren zum Aufschluß von Chromerzen |
FI61855C (fi) * | 1980-08-05 | 1982-10-11 | Outokumpu Oy | Foerfarande foer framstaellning av en jaernfri krom(iii)foerening |
DE4236202C2 (de) * | 1992-10-27 | 1994-07-21 | Bayer Ag | Verfahren zur rückstandsarmen und hochauszehrenden Erzeugung von Natriumdichromat |
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2003
- 2003-03-19 WO PCT/CN2003/000199 patent/WO2004083123A1/zh not_active Application Discontinuation
- 2003-03-19 US US10/549,594 patent/US7968066B2/en not_active Expired - Fee Related
- 2003-03-19 AU AU2003227163A patent/AU2003227163A1/en not_active Abandoned
Patent Citations (3)
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CN1226512A (zh) * | 1998-02-20 | 1999-08-25 | 中国科学院化工冶金研究所 | 铬酸钠的清洁生产方法 |
CN1240763A (zh) * | 1998-06-29 | 2000-01-12 | 龙口市明光化工厂 | 纯氧碱熔法制取铬酸钠和重铬酸钠的方法 |
CN1410358A (zh) * | 2001-10-08 | 2003-04-16 | 中国科学院过程工程研究所 | 铬酸钾的清洁生产方法 |
Cited By (9)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
CN101817561A (zh) * | 2010-04-12 | 2010-09-01 | 中国科学院过程工程研究所 | 一种铬铁矿加压浸出清洁生产铬酸钠的方法 |
CN101844810A (zh) * | 2010-04-29 | 2010-09-29 | 中国科学院过程工程研究所 | 一种由铬酸钾生产铬酸钠的方法 |
CN102020317A (zh) * | 2010-12-27 | 2011-04-20 | 中国科学院过程工程研究所 | 一种以铬酸钡为中间体由铬酸钾制备重铬酸钠的方法 |
CN102320661A (zh) * | 2011-09-06 | 2012-01-18 | 重庆民丰化工有限责任公司 | 三相催化氧化制备可溶性铬酸盐的工艺 |
CN102320661B (zh) * | 2011-09-06 | 2013-11-27 | 重庆民丰化工有限责任公司 | 三相催化氧化制备可溶性铬酸盐的工艺 |
CN104341004A (zh) * | 2013-07-25 | 2015-02-11 | 中国科学院过程工程研究所 | 一种铬铁矿加压浸出制备铬酸钾的新工艺 |
CN104195346A (zh) * | 2014-09-15 | 2014-12-10 | 中国科学院过程工程研究所 | 一种高效提取提钒尾渣中铬的清洁工艺方法 |
CN109957661A (zh) * | 2019-04-29 | 2019-07-02 | 中南大学 | 一种微波强化从镍铁冶炼渣中回收铬并制备轻质隔热材料的方法 |
CN111453770A (zh) * | 2020-03-31 | 2020-07-28 | 有研工程技术研究院有限公司 | 一种尺寸可控的高纯度碱金属铬酸盐晶体粉末及制备方法 |
Also Published As
Publication number | Publication date |
---|---|
US7968066B2 (en) | 2011-06-28 |
US20060188419A1 (en) | 2006-08-24 |
AU2003227163A1 (en) | 2004-10-11 |
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