What is Alumina 

Alumina is a high hardness compound.Alumina has a melting point of 2054℃ and a boiling point of 2980℃，it is ionic crystal that can be ionized at high temperatures and it is often used  to make refactory material.Industry alumina is produced from bauxite and diaspore.For Aluminium oxide  with high purity ,it is generally produced by chemical methods.

Alumina is a stable oxide of aluminum and is also called bauxite in mining,ceramics and materials science.The appearance of alumina is a white solid that is difficult to dissolve in water.It is ordorless,tasteless and extremely hard.It is easy to absorb moisture and does not deliquesce.It  can be dissolved inorganic acids and alkaline solutions,but is almost insoluble in water and non-polar organic solvents 

Common used of Alumina 

1.The medium

Alumina powder is often used as a medium for chromatography.

2 Manufacturing Strenthened glass.Corundum powder has high hardness and can be used as abrasive,polishing powder,high temprature sintered alumina,called artificial corundum or artificial gemstone ,and it can be used to make dimonds in merchanic bearing and watches.Alumina is also used as a high temperature Refractory, making refractory bricks, crucibles, porcelain, artificial gemstones, etc. . Alumina is also used to make aluminium. Bearings for precision instruments, diamonds for clocks, grinding wheels, polishes, Refractory and electrical insulators. A brightly colored ornamental gem. The material of laser made from artificial ruby single crystal. In addition to natural minerals, it can be made by Aluminum hydroxide. Aluminium oxide is the reason why aluminium is not easy to be corroded in air. Pure aluminum reacts easily with oxygen in the air to form a thin film of aluminum oxide covering the surface of aluminum exposed to air. This thin film of alumina prevents the aluminium from being further oxidized.

 3. Bauxite-Type Alumina: 

α-Alumina is insoluble in water and acid, which is also called Alumina in industry and is the basic raw material for making aluminum. It is also used for making all kinds of refractory bricks, refractory pots, refractory pipes and high temperature resistant experimental instruments It is also used as abrasives, flame retardants, fillers, etc. . high-purity alumina is also used as raw material in the production of artificial corundum, artificial ruby and Sapphire. It is also used in the production of modern large-scale integrated circuits. 

γ-Alumina: Type Alumina is a porous substance with an internal surface area of several hundred square meters per gram and high adsorption activity. Industrial products are usually colorless or micro-pink cylindrical particles, good pressure resistance. It is widely used as adsorbent, catalyst and catalyst carrier in petroleum refining and petrochemical industry, deacidification agent for transformer oil and turbine oil in industry, and also used in chromatographic analysis, its drying capacity is no less than tetraphosphorus decaoxide, after use,  heating it for 6-8 hours  below 175 °C,it  can be recycled reuse.

β-Alumina: it has the ability of ion conduction (allowing Na to pass through) , with-bauxite as electrolyte to make sodium-sulfur batteries. Because of the large storage capacity per unit weight of the battery, it can carry out high current discharge, so it has a broad application prospect. 

Abrasice Alumina: Alumina is suitable for a variety of wet and dry treatment process, it can grinding any workpiece rough surface to be fine, it is one of the most affordable abrasive. This kind of synthetic abrasive with sharp water-caltrop has a hardness second only to that of diamond, and it is especially suitable for use when the iron pollution is strictly required. For the roughest cutting, but it also can be made to be pebbles on the size of precision workpiece processing, to achieve a very low roughness. Because of its high density, Sharp, diamond structure, it is one of the fastest cutting abrasives. Alumina is used to make brown corundum by electrically melting high-quality bauxite, while high-quality aluminate is used to make powder corundum and white corundum. Their natural crystal structure makes them high hardness and fast cutting performance. At the same time, they are often used as the raw materials for bonding and coating abrasives. Alumina can be recycled many times according to  the number of cycles and material grade and specific process, most of the standard abrasive blasting equipment can be used.

 4. Ceramic Industry, alumina is divided into calcined alumina and ordinary industrial alumina, calcined alumina is the necessary raw material to produce antique brick, and industrial alumina can be used to produce microcrystalline stone, in traditional glazes, alumina is often used as whitening. Because archaize brick and microcrystalline stone received market favour, the dosage of alumina also is increasing year by year.