Method for decontaminating potassium sub-molten salt soluble crystal liquid and preparing chromic oxide

A sub-molten salt and chromium oxide technology is applied in the field of solution crystal liquid removal and chromium oxide preparation after the reaction of chromium salt production sub-molten salt. problems such as long aging time, to achieve the effect of easy filtration and washing, low chromium band loss, and coarse particles
CN103570069AActive Publication Date: 2014-02-12INST OF PROCESS ENG CHINESE ACAD OF SCI
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
INST OF PROCESS ENG CHINESE ACAD OF SCI
Publication Date
2014-02-12

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Abstract

The invention discloses a method for decontaminating potassium sub-molten salt soluble crystal liquid and preparing chromic oxide. The method comprises the following steps: (1) introducing CO2 to potassium sub-molten salt soluble crystal liquid, neutralizing potassium hydroxide in the solution, then adding seed crystals, controlling the temperature of the solution at 30-90 DEG C and removing aluminum and silicon; (2) introducing CO2 to the solution obtained in the step (1) to carry out room-temperature pre-carbonation; (3) adding a reducing agent to pre-carbonated feed liquid obtained in the step (2), heating to 120-170 DEG C, and carrying out heat preservation and solid-liquid separation after reaction is ended, so as to obtain a chromium hydroxide filter cake; and (4) drying and calcining the chromium hydroxide filter cake obtained in the step (3), so as to obtain a chromium sesquioxide product. By adopting a pre-acidification mode, the reducing agent is not added in pre-carbonation; no CO2 is introduced after the pre-carbonated feed liquid and the reducing agent are mixed; the method is high in conversion rate of hydrothermal reduction, fewer in intermediate products, high in total yield of chrome, high in purity of the sintered chromic oxide and fewer in impurities by controlling a proper pre-carbonation condition.
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Description

technical field

[0001] The invention relates to the field of chromium salt production, in particular to a new method for removing impurities in a crystal solution and preparing chromium oxide after the sub-molten salt reaction of chromium salt production. Background technique

[0002] At present, the production methods of chromium salt are divided into calcium roasting, calcium-free roasting and liquid phase oxidation. Calcium roasting technology will be gradually eliminated due to low conversion rate and large amount of slag discharge. At present, the main methods of chromium salt production in my country are calcium-free roasting and sub-molten salt liquid phase oxidation. The main purpose is to reduce the emission of harmful chromium slag and reduce the pollution of the chromium salt production industry to the environment.

[0003] The sub-molten salt liquid phase oxidation method has a high conversion rate, and can convert 99% of chromium into chromate into the leaching...

Claims

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