Method for producing high-quality sodium bichromate

A production method, the technology of red alum sodium, applied in the direction of chromate/dichromate, etc., can solve the problems of no organic combination, high gas source requirements, high production cost, etc.

Active Publication Date: 2013-07-10
SICHUAN YINHE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

But the CO of the carbonization method 2 Enrichment has high requirements on gas source, which is restricted to a certain extent; electrolysis has high requirements on the quality of sodium chromate solution, high power consumption in operation, and high production cost, so it is only suitable for areas with low electricity costs
[0006] It can be seen that although the above various processes have made great progress in the traditional sodium rufium manufacturing process, each has its own advantages, but basically the sodium chromate preparation section and the sodium chromate acidification section are carried out separately, and there is no organic combination before and after, so it is difficult to realize the circulation of materials use

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0062] Using chromium content of 50% by weight of ferrochrome with an average particle size of 75μm as raw material, 630g of ferrochrome and 320g of soda ash, and a chromium-containing sodium carbonate aqueous solution containing 2.3% by weight of chromium (calculated as sodium alum) and sodium carbonate content of 14.5% by weight After 2200 g was mixed, 800 g of water was added for beating to obtain an aqueous slurry. The aqueous slurry was placed in a 5L kettle-type oxidation reactor. When it was heated to 150℃, oxygen content of 99.9% by volume was continuously introduced. The reactor continued to heat up to 280℃, and the exhaust valve of the reaction tower was opened to keep the inside of the tower constant. The pressure is 8.0 MPa. CO detected in exhaust gas 2 The content is 78% by volume, and it is directly used in the subsequent process of sodium chromate carbonization and acidification to produce sodium alum. After 1.5h, stop oxygen and exhaust. After the reaction comp...

Embodiment 2

[0065] Using chromium content of 65% by weight of ferrochrome with an average particle size of 60μm as raw material, 32kg of ferrochrome and 16kg of caustic soda, and 1.2% by weight of chromium (calculated as sodium alum) and sodium carbonate content of 16.8% by weight of chromium-containing sodium carbonate After 120 kg was mixed, 150 kg of water was added for beating to obtain an aqueous slurry. Place the aqueous slurry at 1m 3 In the tower oxidation reaction tower, when heated to 180°C, oxygen gas with a content of 99% by volume was continuously introduced, the reaction tower continued to heat up to 250°C, and the reaction tower exhaust valve was opened to keep the internal pressure of the tower at 6.0MPa. CO detected in exhaust gas 2 The content is 85% by volume, collected and used directly in the subsequent process of sodium chromate carbonization and acidification to produce sodium alum. After 1.0h, stop oxygen and exhaust gas. After the reaction completed liquid is coole...

Embodiment 3

[0068] Using chromium content of 55% by weight of ferrochrome with an average particle size of 45μm as raw material, 160kg of ferrochrome and 100kg of sodium chromate, and 3.4% by weight of chromium (calculated as sodium alum) and sodium carbonate content of 20% by weight of chromium-containing carbonic acid After 430 kg of sodium aqueous solution was mixed, 150 kg of water was added for beating to obtain an aqueous slurry. Place the aqueous slurry at 1m 3 In the tower-type oxidation reaction tower, when it is heated to 130°C, oxygen with a content of 99% by volume is continuously introduced, the reaction tower continues to be heated to 260°C, and the exhaust valve of the reaction tower is opened to keep the internal pressure of the tower at 6.5MPa. CO detected in exhaust gas 2 The content is 80% by volume, collected and used directly in the subsequent process of sodium chromate carbonization to produce sodium sulphate. After 2h, stop oxygen and exhaust gas. After the reaction ...

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Abstract

The invention relates to a method for producing sodium bichromate. The method comprises the following steps: 1) performing hydrothermal oxidation on slurry of chromium-containing sodium carbonate, ferrochromium and soda and water to obtain sodium chromate and carbon dioxide, and removing carbon dioxide; 2) separating the obtained reaction mixture to obtain a sodium chromate solution and iron slag; 3) concentrating the obtained sodium chromate solution to 600-1400g / L; 4) carbonizing and acidizing the sodium chromate concentrated solution by using the carbon dioxide removed in the step 1), thus obtaining a sodium dichromate solution and chromium-containing sodium bicarbonate; and 5) decomposing the obtained chromium-containing sodium bicarbonate into chromium-containing sodium carbonate and carbon dioxide, returning the chromium-containing sodium carbonate to the step 1), and returning carbon dioxide to the step 4). According to the method, the processes of preparing the sodium chromate solution and acidizing the sodium chromate are organically combined, comprehensive recycling of Na+ and CO2 is realized, no waste residues are generated in the whole production process, the discharge of three wastes is greatly reduced, the method is a low-carbon, cyclic and clean type process for production of sodium bichromate, and the purity of the produced sodium bichromate is high.

Description

Technical field [0001] The present invention relates to a method for producing high-quality sodium sulphate, and more specifically to a method for the production of high-quality sodium sulphate in a cycle, low carbon and clean. Background technique [0002] Sodium alum is an important basic chemical raw material, mainly used in the production of chromic anhydride, chrome yellow, chrome oxide green and other chemical products. It is used as an auxiliary in the printing and dyeing industry, electroplating industry and leather industry. It is also widely used in the chemical industry and the pharmaceutical industry. [0003] At present, the production of sodium alum in the chromium salt industry is mainly composed of a sodium chromate preparation section and a sodium chromate acidification section to produce sodium alum. In the sodium chromate preparation section, chromite oxidative roasting mainly uses chromite as raw material, mixes with 90-120% of the theoretical amount of sodium c...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01G37/14
Inventor 李先荣陈宁董明甫王方兵黄先东
Owner SICHUAN YINHE CHEM
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