Aluminum oxide is one of the most important ingredients in the production of metallic aluminum. It is also used as an abrasive and in various chemical applications. It is often found in crystalline form, but it can be obtained in non-crystalline form as well.
Aluminium oxide is produced from bauxite, an ore containing 30 to 55% Al2O3. It is formed when bauxite is dissolved in caustic soda and then heated. The slurry is then filtered to remove impurities.
Bauxite is the main ore of aluminum. It contains iron oxides, silicates, and quartz. It is then crushed, and slurry is then heated to 110 to 270 degC. It is then filtered to remove "red mud" impurities.
It is then dried in a drying oven. It is then transported to a foundry for rolling slabs. The process is repeated until the product is of uniform thickness.
When the liquid aluminium is stored in a room without humidity, the metal forms a thin layer of aluminium oxide. The layer prevents the metal from reacting with water, which helps protect it from corrosion. If the oxide is damaged or corroded, the aluminium reverts to its original state, and a highly flammable hydrogen gas is released.
Aluminium oxide has a high melting point, making it a suitable material for the manufacture of high-temperature appliances. It is used as an insulator, adsorbent, and a substrate for integrated circuits. It is also a strong electrical insulator and has good corrosion resistance.