Method for preparing metallic aluminum or aluminum-magnesium alloy by utilizing pulverized fuel ash

Abstract

The invention belongs to the field of non-ferrous metallurgy and relates to a method for preparing metallic aluminum or an aluminum-magnesium alloy by utilizing pulverized fuel ash. According to the technical scheme of the invention, the method comprises the following steps: preparing aluminum chloride by adopting acid leaching of pulverized fuel ash, wherein the adopted electrolyte system consists of a flux, a solute and an additive, and the flux comprises the following components in percentage by mass: 0-60 percent of NaCl, 25-75 percent of KCl and 0-66 percent of MgCl2; adding a solute AlCl3 which accounts for 5-50 percent of the mass of the flux, an additive LiCl which accounts for 0-5 percent of the mass of the flux, 0-5 percent of an additive KF, 0-5 percent of an additive MgF2 or 0-5 percent of an additive AlF3, wherein the solute AlCl3 is added from the bottom of the electrolytic cell, the interpolar voltage is controlled to be 2.3-3.3V, the cathode-current density is 0.5-1.5A / cm<2>, and the electrolysis temperature is 450-500 DEG C; and producing chlorine on one side of the anode in the electrolysis process, recycling chlorine, and depositing solid metallic aluminum or the aluminum-magnesium alloy on one side of the cathode. According to the method disclosed by the invention, the power consumption is saved, the electrolysis temperature is low, the production cost is low, the problems of aluminum chloride evaporation and generation of dendritic crystals during electrolysis are solved, the environmental pollution is avoided, and the equipment is easy to realize.

Description

technical field [0001] The invention belongs to the field of nonferrous metallurgy, and relates to a method for preparing metallic aluminum or aluminum-magnesium alloy with fly ash. 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 aluminum hydroxide, and...

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.

[0006] In the early research on aluminum chloride electrolysis, most of the sources of aluminum chloride were obtained through the chlorination of alumina. The production cost was relatively high, coupled with some difficulties in engineering, it has not been applied industrially.

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