A kind of hydrochloric acid leaching bauxite hydrochloric acid leaching step by step electrolysis to prepare alumina and its comprehensive utilization method

Abstract

A step-by-step electrolytic preparation of alumina by hydrochloric acid leaching of bauxite and a comprehensive utilization method, including the following steps: after hydrochloric acid leaching, solid-liquid separation and purification of bauxite, a ferric chloride mixed solution and an aluminum chloride mixed solution are obtained ; Separate and purify the aluminum chloride mixed solution and the ferric chloride mixed solution respectively to obtain scandium chloride and gallium chloride, as well as aluminum chloride and ferric chloride aqueous solutions; set the electrolysis voltage and current density to combine aluminum chloride and chloride The aqueous iron solution undergoes two-step electrolysis to obtain aluminum hydroxide, hydrogen and chlorine respectively; iron hydroxide, hydrogen and chlorine; the generated hydrogen and chlorine are prepared into hydrochloric acid solution and returned to the leaching section for recycling; aluminum hydroxide is roasted to obtain metallurgical grade alumina or the chemical aluminum oxide. The present invention uses an electrolytic method to recover alumina in bauxite. Compared with the traditional acid method, the present invention eliminates evaporation, concentration and equipment, simplifies operations, greatly reduces costs, and the product has higher purity.

Description

Technical field: [0001] The invention belongs to the technical field of alumina production, and in particular relates to a step-by-step electrolytic preparation of alumina by hydrochloric acid leaching of bauxite and a comprehensive utilization method. Background technique: [0002] Three bauxites of gibbsite type, boehmite type and diaspore type are the raw materials for the production of aluminum industry, and there are also two or more mixed types of bauxite. my country is rich in bauxite resources, but the vast majority of bauxite resources in my country belong to the diaspore type ore, and the diaspore type bauxite has the characteristics of perfect crystallization and compact structure. Especially difficult. The bauxite with aluminum-silicon ratio between 4-7 accounts for about 80% of the total reserves in my country's proven bauxite reserves. This determines that when my country uses the pure Bayer process to produce alumina, the dissolution conditions require high t...

AI Technical Summary

Problems solved by technology

[0010] The object of the present invention is, aiming at the technical problems of long flow process, high energy consumption and inability to comprehensively utilize in the prior art, the present invention provides a method for preparing alumina by step-by-step electrolysis of bauxite hydrochloric acid leaching and its comprehensive utilization method. By reacting bauxite with hydrochloric acid, the bauxite can be obtained through step-by-step leaching, solid-liquid separation, and purification to obtain ferric chloride mixed solution and aluminum chloride mixed solution. From the mixed solution of aluminum chloride and ferric chloride Separation and extraction of scandium chloride and gallium chloride, after purification, high-purity scandium chloride and gallium chloride products can be obtained; the aluminum chloride aqueous solution and the ferric chloride aqueous solution are subjected to step-by-step electrolysis; the hydrochloric acid produced in the first step of electrolysis is returned to leaching section; the second step is to electrolyze respectively to obtain aluminum hydroxide products, iron hydroxide products, hydrogen and chlorine, wherein hydrogen and chlorine react to prepare hydrochloric acid, which is reused in the leaching of bauxite and effectively recovers alumina in bauxite At the same time, the recycling of hydrogen and chlorine can be realized; the aluminum hydroxide can be roasted to obtain metallurgical grade alumina or chemical alumina

Images