1, the diversification of alumina properties makes it have a wide range of uses, but more than 90% is used for making metal aluminum, the rest is used as plastic and other polymer products filler, adsorbent and catalyst, medicine, cosmetics and chemical products raw materials, ceramics, abrasives and refractory materials and so on. China is used to calling it special alumina or multi-variety alumina. There is a growing trend in its variety and needs. 2, aluminum oxide is the main raw material of metal aluminum electrolytic process, the more pure aluminum used, the more pure aluminum. Because it is more difficult to purify aluminum than alumina, the purification of alumina before electrolysis is very important. Alumina is one of the main components of the Earth's crust, and aluminum ore mainly includes bauxite Al2O3·2H2O, alum stone (AlO)2SO4·9H2O, aluminum clay H2Al(SiO4)·H2O and so on. China's aluminum mineral resources are very rich, such as Taiwan, Shandong, Shanxi, Guizhou, Kunming, Hebei, Henan, Liaoning and other places have large reserves. Natural bauxite is the best raw material for making alumina, the general content can reach 40% to 60%, and the rest are mainly impurities such as silica, iron oxide and dispersed elements. Aluminum oxide can be separated from other impurities by their commonness and individuality in chemical properties, and there are two main purification methods: acid method and alkali method. Activated alumina, gamma alumina, is a porous substance with an internal surface area of up to hundreds of square meters per gram, and has extremely high activity, which can adsorb water vapor and many gases and liquid molecules, and is commonly used as an adsorbent, catalyst carrier and desiccant. 3, the artificial alumina fiber is aluminum oxide as the main component, containing about 5% silicon dioxide (to stabilize the crystal phase of aluminum oxide), commonly used as a variety of heat treatment furnace in the steel industry and petrochemical cracking furnace and other thermal insulation lining, nuclear reactor and space shuttle insulation materials and light alloy reinforcement materials. Alumina fiber is a polycrystalline alumina fiber. It is manufactured by colloidal method or organic fiber impregnation method (organic fiber precursor method), and its structure is in a microcrystalline form, so as to exclude the shortcomings of recrystallization powder of the fiber made by melting and blowing method. This fiber has great strength at room temperature and high temperature, high temperature resistance, small bulk density, good chemical stability, strong insulation, dielectric and sound absorption properties.