Method for producing aluminum oxide by treating low-grade bauxite with ammonia-alkali combination method

Abstract

The invention discloses a method for producing aluminum oxide by treating low-grade bauxite with an ammonia-alkali combination method. The method comprises the following main steps: performing mineral dressing and silicon removal on the low-grade bauxite; selecting concentrates, performing processes of high-pressure dissolution, red mud separation and washing, crystal seed decomposition, aluminum hydroxide separation and washing, aluminum hydroxide calcination and the like on the selected concentrates to produce metallurgical-grade sand-shaped aluminum oxide, and recycling a seed precipitation solution after evaporation and allocation; and selecting tailings, performing low-temperature leaching by adopting an ammonium hydrogen sulfate solution, and performing silicon residue separation and washing, ammonia separation aluminum deposition and coarse aluminum hydroxide separation and washing to obtain coarse aluminum hydroxide. By adopting the method disclosed by the invention, the organic combination of a mineral dressing and silicon removing process, a high-temperature Bayer method process for selecting concentrates and an ammonium hydrogen sulfate solution low-temperature leaching process for selecting tailings is achieved, the advantages of each process are brought into full play, and the utilization ratio of a low-grade bauxite resource is maximized while high-quality metallurgical-grade sand-shaped aluminum oxide is produced.

Description

technical field [0001] The invention belongs to a utilization method of low-grade bauxite, in particular to a method for producing alumina by treating low-grade bauxite with an ammonia-alkali combined method. Background technique [0002] Over the years, with the rapid development of the national economy, my country's aluminum industry has achieved unprecedented development. Alumina, as a raw material for electrolytic aluminum, has also developed rapidly. It has become the world's largest producer of alumina. At present, my country's alumina enterprises have reached 40 There are several companies with a production capacity of 60 million tons / year under construction and 60 million tons / year, including nearly 40 million tons / year of domestic bauxite. However, my country is a country with relatively poor bauxite resources. At present, my country's identified and inferred bauxite resource reserves have a low degree of guarantee for my country's alumina industry, and with the cont...

AI Technical Summary

Problems solved by technology

The Bayer method of mineral processing has a low utilization rate of resources, and the recovery rate of alumina is less than 65% when processing medium-grade bauxite, and the recovery rate is even lower when processing low-grade bauxite; the process of series method is long, and there are two major processes of Bayer method and sintering method , the system balance is difficult, and the energy consumption is high

Therefore, none of the currently existing methods are suitable for processing low-grade bauxite

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