Views: 61 Author: SEPPE Publish Time: 2021-01-20 Origin: SEPPE Technologies
Bauxite is mainly composed of three aluminum hydroxides such as diaspore, boehmite, and gibbsite. It often contains impurities such as kaolinite, iron minerals and titanium minerals.
China is rich in bauxite resources and is among the four largest bauxite resources in the world along with Guinea, Australia and Brazil.
However, the countries that produce bauxite for refractories are mainly only a few countries such as Guyana, Brazil and China. Bauxite in other countries has a high iron content and is mostly used for aluminum smelting and grinding materials.
The bauxite referred to in the refractory industry usually refers to bauxite clinker (calcined bauxite) with Al2O3>=48% and low Fe2O3 content after calcination. Most of the bauxite in China is D-K type, which needs to go through three stages of decomposition and dehydration, secondary mulliteization and sintering during the calcination process. The calcined mineral composition forms corundum, mullite and glass phases according to the ratio of Al2O3 and SiO2 in the raw materials. The calcination can be carried out in a shaft kiln, an inverted flame kiln or a rotary kiln. The calcination temperature is generally 1400°C-1600°C. The specific calcination temperature should be determined according to the grade of bauxite.
The calcined bauxite is gray, light yellow and dark gray. The particle size can be unprocessed particle size, coarse particle, or section sand, and fine powder ground by a ball mill, which can be processed according to customer requirements. Calcined bauxite is mainly used to produce high-alumina refractories. It is one of the most important raw materials for shaped and unshaped refractories produced in steel, casting, glass and cement industries. It can also be used to make fused brown corundum.