Aluminum oxide (Al2O3) is a naturally occurring substance. It is a form of aluminium, and it has many important industrial applications. It is used as a filler in plastics and in sunscreen, and it is also a key ingredient in glass.
Alumina is a hard, dense powder with excellent wear resistance. It can be shaped with diamond tools and is often used in ceramic applications. Alumina has many electrical and thermal properties that make it an ideal material for refractories.
Manufacturing alumina is a complex process. Bauxite, which is a natural raw material, is mixed with caustic soda and other ingredients to produce alum?nium hydroxide, which is then deprived of water by sintering or calcination.
Most alumina is produced using a Bayer process. This involves filtration of the clear alumina slurry to remove any impurities. After a short time, the slurry cools and the silicates precipitate out.
The next step in the manufacturing process is to extract the aluminum from the hydrated alumina. This process uses a series of filters and flash tanks to reduce the pressure and heat on the material. It is then moved to a calcination kiln to heat it to about 1800 degrees F, where the metal will crystallize into the desired shape.
alumina has many other applications, including catalysis, a fire retardant, and as a catalyst support in some industrial processes. For example, it is a component in the Claus process, which converts hydrogen sulfide waste gas into elemental sulfur in refineries.