Process method for producing metal aluminium by high-alumina fly ash

Abstract

The invention discloses a process method for producing metal aluminium by high-alumina fly ash, which comprises the following process steps: firstly, dissolving fly ash out, that is, mixing high-alumina fly ash containing not less than 38% of Al2O3 with hydrochloric acid with a concentration of 20-30% to prepare raw pulp, dissolving out alumina in the fly ash at a high temperature through a continuous dissolving mode of heat insulation dissolution by a preheater and an autoclave; secondly, separating and washing acid sludge, and purifying an aluminium chloride solution for impurity removal; thirdly, performing spray drying and dehydration to obtain anhydrous aluminium chloride crystal particles; fourthly, electrolyzing the molten salts, that is, adding the anhydrous aluminium chloride into an aluminium chloride electrolytic tank, dissolving the anhydrous aluminium chloride in a molten electrolyte, wherein the temperature in the electrolytic tank is 670-700 DEG C, performing electrolyzation to obtain aluminium liquid, delivering the aluminium liquid to a casting procedure, performing purification and clarification, then preparing aluminum ingots, delivering the chlorine generated at an anode of the electrolytic tank to a hydrochloric acid preparation procedure; fifthly, preparing hydrochloric acid. The process of the invention obtains aluminum ingots by treating high-alumina fly ash, which make reasonable use of fly ash.

Description

technical field [0001] The invention relates to a process method for producing metal aluminum from high-alumina fly ash. Background technique [0002] At present, the electrolytic aluminum industry in the world mainly uses alumina as raw material, and alumina (Al 2 o 3 ) and cryolite (3NaF·AlF 3 ) at a high temperature of more than 900 ° C to form a molten electrolyte to form a basic electrolyte component, which is electrolyzed in an electrolytic cell to obtain metal aluminum. [0003] Alumina production mainly uses bauxite as raw material and is produced by the Bayer process. Alumina has many uses, but most of it (more than 90%) is used as raw material for electrolytic aluminum plants to produce metal aluminum. [0004] my country is the world's largest producer of alumina and metallic aluminum. The output of alumina and electrolytic aluminum accounts for about 40% of the world's total output. However, my country's bauxite resources are poor, and the ore grade is low. It...

AI Technical Summary

Problems solved by technology

[0013] The technical problem to be solved by the present invention is to provide a process for producing metallic aluminum from high-alumina fly ash, which combines the production process of alumina and electrolytic aluminum into one, simplifies the process flow of producing aluminum from fly ash, and reduces the engineering cost. Investment and production costs, so that enterprises have better economic benefits, in order to overcome the existing technology existing in the huge amount of lime, large amount of red mud, low concentration of sodium aluminate solution, high production energy consumption, or solution iron removal and removal Complex and difficult, high requirements for corrosion resistance of equipment and materials, etc.

Images