The production of aluminum ingot is composed of bauxite mining, alumina production, aluminum electrolysis and other production links.
The bauxite is extracted first, the bauxite powder is produced by water washing, grinding and other processes, and then the aluminum oxide is obtained by four complex processes such as roasting. There are three types of bauxite used to produce aluminum oxide: gibbsite, diaspore and diaspore.
92% of the proven global reserves of bauxite are weathered laterite type bauxite, which belongs to gibbsite type. These bauxites are characterized by low silicon, high iron and high alumina silica ratio, and are concentrated in western Africa, Oceania and central and South America. The remaining 8% is sedimentary bauxite, belonging to diaspore type and diaspore type, with medium and low grade, mainly distributed in Greece, the former Yugoslavia and Hungary.
Due to the different characteristics of three kinds of bauxite, different alumina production enterprises adopt different production processes, mainly including Bayer process, alkali lime sintering process and Bayer sintering combined process. Generally, high-grade bauxite is produced by Bayer process, while medium and low-grade bauxite is produced by combined process or sintering process. Because of its simple process and low energy consumption, Bayer process has become the most important method in alumina production. Its output accounts for about 95% of the total alumina production in the world.
Aluminum oxide in the role of strong current, electrolytic aluminum metal, this process is called electrolytic aluminum.