A method for producing metal aluminum or aluminum-magnesium alloy with low-grade bauxite

Abstract

The invention belongs to the field of non-ferrous metallurgy, and in particular relates to a method for producing metal aluminum or aluminum magnesium alloy from low grade bauxite. The technical scheme of the invention is as below: first acid leaching is carried out on the low grade bauxite for preparing aluminum chloride, and an electrolyte system comprises a flux, a solute and additives. The flux comprises 0-60 wt.% of NaCl, 25-75 wt.% of KCl and 0-66 wt.% of MgCl2; then the solute AlCl3 accounting for 5-50 wt.% of the flux, an additive LiCl accounting for 0-5 wt.% of the flux, an additive KF accounting for 0-5% of the flux, an additive MgF2 accounting for 0-5 wt.% of the flux or an additive AlF3 accounting for 0-5 wt.% are added, wherein the solute AlCl3 is added from the bottom of electrolytic bath; the interpolar voltage is controlled at 2.3-3.3 V, the cathode current density is at 0.5-1.5 A / cm<2>, and the electrolysis temperature is 450 -500 DEG C; in the process of electrolysis, the anode generates chlorine gas, which is recycled, and aluminum or aluminum alloy precipitates at the cathode. The method of the invention has low power consumption, low electrolytic temperature and low production cost, solves the problem of aluminum chloride evaporation and dendrite generation electrolysis, causes no environmental pollution, and is easy in equipment realization.

Description

technical field [0001] The invention belongs to the field of nonferrous metallurgy, and in particular relates to a method for producing metallic aluminum or aluminum-magnesium alloy with low-grade bauxite. Background technique [0002] The traditional metal aluminum production method is the Hall-Heroult (Hall-Heroult) method. In 1886, American Hall and Frenchman Herout simultaneously invented the cryolite-alumina molten salt electrolysis method to produce aluminum, that is, using carbon Plain material is used as electrode material, cryolite is used as solvent, alumina is used as solute, and the method for producing aluminum by molten salt electrolysis at a temperature of 950-1000°C. The source of alumina so far is mainly obtained by alkali leaching, that is, using alkali (industrial caustic soda NaOH or soda ash Na 2 CO 3 ) to process bauxite so that the alumina in the ore becomes soluble sodium aluminate. The purified sodium aluminate solution is analyzed to separate out...

AI Technical Summary

Problems solved by technology

The main features of these two methods are that the electrolysis temperature is low, and the aluminum chloride vapor is easy to control, but the metal is in the state of crystal particles, which is difficult to collect. In addition, the easy formation of dendrites is the biggest defect of this method.

[0005] In the early research on aluminum chloride electrolysis, most of the sources of aluminum chloride were obtained through the chlorination of alumina. Coupled with some difficulties in engineering, it has not been applied industrially.

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