For getting aluminum from bauxite normally means departing aluminum trioxide from bauxite. For reaching the purpose there are three ways including: acid method, alkali method, acid-base combined method and thermal method. However, the acid method, acid-base combined method  and thermal method are not used in large quantities in the industry due to safety and economic benefits. The alkaline method is used in industrial production.

There are 3 methods for extraction alumina trioxide using alkaline method which are calcination method, bayer method and combined method. We will take calcination method as an example.

Calcination method: Putting a certain amount of calcium carbonate into bauxite, a substance whose main component is sodium aluminate is formed after high temperature calcination in a rotary kiln. Finally alumina is obtained after dissolution, crystallization and roasting.