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Chromium salt mud treatment method

A treatment method, chromium salt technology, applied in chemical instruments and methods, chromium compounds, inorganic chemistry, etc., can solve problems such as easy production of other impurities, difficult trivalent chromium, leaching, etc.

Active Publication Date: 2015-11-04
INST OF PROCESS ENG CHINESE ACAD OF SCI
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  • Abstract
  • Description
  • Claims
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Problems solved by technology

[0006] The method for treating waste slag containing chromium in the above-mentioned prior art cannot be directly applied to chromium salt mud in chlorate plants, and the hexavalent chromium ions wrapped in the particles in the chromium salt mud are not easy to be removed, and the dry detoxification consumes a lot of energy. Secondary pollution occurs, the direct reduction method cannot completely remove chromium and other impurities are easily produced, and the leaching method is difficult to leach the trivalent chromium wrapped inside the particles. Harmless and Chromium Separation Treatment of Salt Plant Chromium Salt Sludge

Method used

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  • Chromium salt mud treatment method

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Experimental program
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Embodiment approach

[0093] A processing method for chromium salt mud, comprising the following steps:

[0094] (1) Mix chromium salt mud and water at a mass volume ratio (g / mL) of 1:(2-20) and heat to 30-100°C for elution for 0.2-4 hours. After liquid-solid separation, the surface-adsorbed chromium and soluble Salt filtrate and filter residue, the filtrate is returned to the chlorate production system for recycling;

[0095] (2) Mix the filter residue obtained in step (1) with water at a mass volume ratio (g / mL) of 1:(2-20) and mix evenly, with the molar ratio of oxidant and chromium in the filter residue being (5-50):1 Add the oxidizing agent in an amount of leaching agent, mix and heat to 30-200°C for 0.5-4h to oxidize, add the leaching agent with the molar ratio of leaching agent to calcium element in the filter residue (0.5-5):1, mix and heat at 30-200°C Leach for 0.5 to 6 hours, and obtain the leach liquid and leach residue after liquid-solid separation;

[0096] (3) The leached slag obtai...

Embodiment 1

[0100] (1) Mix 40g of chromium salt mud and water at a mass volume ratio (g / mL) of 1:2 and heat to 100°C for elution for 0.2h. After liquid-solid separation, the filtrate and filter residue containing chromium adsorbed on the surface and soluble salts are obtained. The filtrate is returned to the chlorate production system for recycling;

[0101] (2) Mix the filter residue obtained in step (1) with water at a mass volume ratio (g / mL) of 1:20, add hydrogen peroxide at a molar ratio of 5:1 to the chromium element in the filter residue, mix and heat to 30 Oxidation at ℃ for 4 hours, adding potassium carbonate in the amount of potassium carbonate and calcium element in the filter residue at a molar ratio of 5:1, mixing and heating at 200℃ for 0.5h, and obtaining the leaching solution and leaching residue after liquid-solid separation;

[0102] (3) The leaching slag obtained in step (2) is washed in 5 stages to obtain dechrome tailings, the liquid-solid ratio (mL / g) of washing is 2...

Embodiment 2

[0107] (1) Mix 40g of chromium salt mud and water at a mass volume ratio (g / mL) of 1:20 and heat to 30°C for elution for 4 hours. After liquid-solid separation, the filtrate and filter residue containing chromium adsorbed on the surface and soluble salts are obtained. Return to the chlorate production system for recycling;

[0108] (2) Mix the filter residue obtained in step (1) with water at a mass volume ratio (g / mL) of 1:2, add hydrogen peroxide in an amount of 5:1 molar ratio of the chromium element in the hydrogen peroxide to the filter residue, mix and heat to 200 Oxidation at 0.5°C for 0.5h, adding sodium carbonate at a molar ratio of 0.5:1 to the calcium element in the filter residue, mixing and heating at 30°C for 6h, and obtaining the leach solution and leach residue after liquid-solid separation;

[0109] (3) The leached slag obtained in step (2) is subjected to two-stage washing to obtain dechrome tailings, the liquid-solid ratio (mL / g) of the washing is 8:1, the w...

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Abstract

The invention relates to a chlorate factory chromium salt mud harmless treatment and chromium separation and recovery method. The method comprises mixing chromium salt mud and water, heating the mixture, carrying out elution, carrying out solid-liquid separation to obtain filtrate and filter residue, mixing the filter residue and water to obtain a uniform mixture, carrying out oxidation and chromium impregnation, carrying out solid-liquid separation to obtain leachate and leaching residue, washing the leaching residue to obtain dechromed tailings, recycling the washing solution after washing, adjusting pH of the leachate, adding a reducer into the leachate for reduction chromium removal, carrying out solid-liquid separation to obtain a dechromed solution and chromium hydroxide, carrying out crystallization separation on the dechromed solution to obtain sulfate and recycling the mother liquid obtained by crystallization separation. The method can realize high efficiency separation and recovery of chromium in chlorate factory chromium salt mud and thorough removal of toxicity of the dechromed tailings. The method has simple processes, a low cost and a good industrial application prospect.

Description

technical field [0001] The invention belongs to the application field of hydrometallurgy and inorganic salt industry, and in particular relates to a treatment method for chromium salt mud, in particular to a harmless treatment method for chromium salt mud in a chlorate factory and a chromium separation treatment method. Background technique [0002] The composition of chromium salt mud in chlorate plant is complex, including white mud and yellow mud. Due to different production methods, the composition and phase of the two mud are quite different. The impurity content of the raw salt in the brine process is high. When the brine is refined, soda ash and caustic soda are added to precipitate calcium and magnesium ions to produce white mud whose main components are calcium carbonate, sodium chloride and a small amount of calcium sulfate, calcium chromate and sodium chromate. Sulfate ions mainly enter the process system through raw material salt. In order to make the electrolyti...

Claims

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Application Information

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IPC IPC(8): C01G37/00
Inventor 徐红彬张红玲张笛田颖庆朋辉裴丽丽胡应燕
Owner INST OF PROCESS ENG CHINESE ACAD OF SCI
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