A kind of auxiliary material recyclable chromium salt production method

Abstract

The invention discloses a method for producing chromium salts with recyclable auxiliary materials, comprising the following steps: (1) raw meal configuration; (2) oxidative roasting transformation; (3) clinker ammonium salt leaching; (4) impurity removal crystallization; (5) ammonium chromate is decomposed; (6) ammonia and / or carbon dioxide obtained after steps (2), (4), (5) are absorbed with a solution to obtain an ammonium salt solution for recycling as a leaching agent. The chromium salt production method of the present invention abandons the use of alkali metal carbonates or hydroxides as auxiliary materials for oxidative decomposition of chromite, and adopts low-cost, easy-to-circulate calcium carbonate and other calcium-containing materials and ammonium salts as the chromium salts The auxiliary materials produced avoid the consumption of a large amount of alkali in the production of chromium salts, eradicate the discharge problem of chromium-containing waste residues such as mirabilite, etc., and realize the recycling of auxiliary materials in the production process of chromium salts economically and efficiently, reducing the material consumption in the production process of chromium salts. , reducing production costs and environmental pollution, and the obtained chromium salt products are of high quality.

Description

technical field [0001] The invention belongs to the technical field of chromium and chromium salt production, and in particular relates to a chromium salt production method with recyclable auxiliary materials. Background technique [0002] Chromium salt series products are widely used in electroplating, leather tanning, pigments, anti-corrosion and other fields due to their special properties, and are indispensable and important raw materials. The main methods of producing chromium salts in industry are calcium roasting method, calcium-free roasting method, molten salt liquid phase oxidation method, etc. These methods all use sodium carbonate, sodium hydroxide or potassium hydroxide, etc. to decompose chromite under an oxidizing atmosphere, and oxidize and convert the insoluble trivalent chromium compound in chromite into soluble sodium chromate or potassium chromate. Aqueous leaching separates chromate from the main impurities in the ore. The obtained sodium chromate or p...

AI Technical Summary

Problems solved by technology

Due to the strong alkalinity of sodium and potassium, the combination of sodium / potassium ions and chromate ions in the solution is strong, and weakly acidic CO 2 The process of converting chromate to bicarbonate and separating bicarbonate often requires high CO 2 Partial pressure (>10atm), low temperature (<30°C) and other harsh conditions, resulting in complex process technology and low production efficiency

In the process of reducing chromate or dichromate by carbon or hydrogen, the sodium / potassium carbonate or sodium / potassium hydroxide formed by the reaction is very easy to have a side reaction with the chromium trioxide product to form the corresponding chromite. In the process of separating alkali, chromite is easily hydrolyzed to form chromium hydroxide, which seriously affects the quality and performance of the product

To sum up, sodium or potassium alkali is mainly used as auxiliary materials in the production of existing chromium salts, and the circulation and regeneration of these alkalis are relatively difficult; the existing recycling and regeneration schemes generally can only realize the circulation of part of the alkali, and the production process requires Control harsh conditions, there are problems such as low production efficiency, high cost, and difficulty in guaranteeing the quality of the obtained products

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