Do You Really Know Alumina?

According to different uses, Alumina is divided into two categories: one is used as raw material of electrolytic aluminum alumina, called metallurgical grade alumina, most of the alumina produced in the world is used for electrolytic aluminum; Another kind of non-metallurgical alumina used in ceramics, chemical, pharmaceutical and other fields, known as special alumina, also called chemical alumina. About 5%-7% are used for this purpose.

Alumina is mainly produced with bauxite as raw material. Alumina hydroxide is produced by Bayer method, sintering method and other processes, and then dehydrated by heating decomposition. It is a white powdery or sandy substance. Because bayer process is simple, low energy consumption, short process, high product quality. At present, most alumina enterprises in the world use bayer process production. Based on the resource characteristics of Bauxite in China, alumina production technology in China starts from sintering process. After more than 50 years of development, it has formed the world's leading technology level, complete process technology and equipment system with diaspore bauxite as raw material alumina industry system.

In the main component of bauxite, the content of alumina is the highest. In the main component of bauxite, the content of alumina is the highest. Industrially, ferroalumina is purified by the Bayer process into alumina:

Heat and dissolve the ore with sodium hydroxide. Iron oxide is insoluble, silicon dioxide dissolves as silicate (Si(OH)62−), and alumina dissolves as aluminate. Industrially, ferroalumina is purified by the Bayer process into alumina:

Filtration, acid treatment, alumina hydroxide precipitation, and then filtration.

The amorphous white alumina powder can be obtained by intense heat aluminum hydroxide.

The hall-Arrow process converts to aluminum.