Method for producing chromic oxide from carbon ferrochrome

Abstract

The invention relates to a method for producing chromic oxide from carbon ferrochrome which is a novel method that is basically different from the chromic oxide preparation technique. The method comprises the following steps: by using carbon ferrochrome with fewer impurity varieties as the raw material, dissolving in a sulfuric acid solution to obtain a chromic sulfate-ferrous sulfate acid hydrolysis solution, efficiently separating chrome and iron in the acid leaching solution by using an ammonium salt efficient iron removal technique, carrying out chrome precipitation, washing and calcination on the purified chromic sulfate solution to obtain a chromic oxide product, keeping the temperature of the chrome precipitation slag, converting with an alkali medium, calcining to obtain an Fe-Cr pigment, and carrying out evaporative crystallization on the ammonium sulfate solution subjected to chrome precipitation to obtain the ammonium sulfate solid. The novel method uses the ferrochrome as the raw material to form an efficient pollution-free chromic oxide preparation technique and synchronously obtain the Fe-Cr pigment and ammonium sulfate product. The technical line has the characteristic of diversified products. The invention provides an environment-friendly economical method for producing chromic oxide, and has wide application prospects.

Description

technical field [0001] The invention relates to a production method of dichromium trioxide, in particular to a production method of using carbon ferrochrome as raw material and preparing dichromium trioxide by sulfuric acid method. Background technique [0002] Chromium trioxide (also known as chromium oxide, Cr 2 o 3 ), sodium dichromate (also known as sodium red alum), chromic anhydride and basic chromium sulfate are the four major products of chromium salt. The main uses of chromium oxide include metallurgy, pigments, abrasives, refractory materials and newly developed melt-blown coatings. Among them, chromium oxide for metallurgy is used to smelt metal chromium, accounting for the largest proportion of output. [0003] There are many kinds of chromium oxide production processes. Large-scale production uses sodium dichromate and ammonium sulfate thermal decomposition method, chromium hydroxide method, and chromic anhydride thermal decomposition method; smaller-scale met...

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Problems solved by technology

The extraction and separation method can extract both chromium and iron. For example, the Beijing Nonferrous Metals Research Institute proposes that the organic phase using primary amine as the extraction agent and kerosene as the diluent can extract Cr 3+ , can be used to separate chromium sulfate and ferrous sulfate; CN101974688A discloses a method for extracting and separating iron from a mixed solution of chromium sulfate and ferric sulfate, using octadecyl dimethyl tertiary amine, octadecyl tertiary amine or Dioctadecyl tertiary amine is used as an extractant to extract ferric sulfate, and the organic phase is back-extracted with alkaline solution to obtain ferric hydroxide and sodium sulfate solution, and the chromium sulfate aqueous phase is directly crystallized to prepare chromium sulfate; although the separation efficiency of the extraction method is relatively high, However, there are many stages, the operating environment is poor, and the process is more complicated.

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