Method for extracting aluminum oxide

Abstract

The invention relates to a method for extracting aluminum oxide. The method comprises the following steps: heating and decomposing ammonium sulfate to generate ammonium hydrogen sulfate or ammonia gas, preparing an ammonium hydrogen sulfate solution, and collecting the ammonia gas for preparing ammonia water; grinding coal ash, mixing the coal ash with the ammonium hydrogen sulfate solution according to a certain ratio, heating while stirring, and reacting to generate ammonium aluminum sulfate; re-crystallizing and purifying ammonium aluminum sulfate to prepare an ammonium aluminum sulfate solution, and reacting with the ammonia water to generate aluminum hydroxide; drying aluminum hydroxide and roasting to generate aluminum oxide. According to the method, aluminum oxide can be extracted from not only the coal ash but also aluminum-containing raw materials such as coal gangue, slag, bauxite, red mud, tailings, kaolin and mullite; the technological process is shorter, equipment is simple, and large-scale industrialization production is easy to realize.

Description

technical field [0001] The invention relates to a method for extracting alumina, in particular to a method for extracting alumina from aluminum-containing raw materials such as fly ash, coal gangue and bauxite by using ammonium sulfate. Background technique [0002] my country's thermal power plants produce hundreds of millions of tons of fly ash every year, and a large amount of coal gangue waste is also produced during the coal mining process. A large amount of low-grade bauxite and tailings are also produced during the bauxite mining process. During the production process of the alumina plant A large amount of red mud is produced. These solid wastes not only occupy a large amount of land for storage, but also cause serious air pollution and water pollution. [0003] The main form of utilization of these solid wastes is to produce building materials, and also to produce alumina with fly ash and coal gangue, which are generally divided into two categories: alkali method and ...

AI Technical Summary

Problems solved by technology

Its main disadvantages are strong corrosion of materials, strict requirements on equipment, complex iron removal process and high cost

[0006] There is also a process of extracting alumina by using ammonium sulfate sintering method. The main disadvantage is that the energy consumption of the sintering process is high, and the temperature of the sintering process is difficult to control and stabilize.

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