Alumina

Alumina is aluminum oxide (Al₂O₃), a hard, thermally stable compound used to produce aluminum and to make ceramics, refractories, and abrasives.

Bayer process: An industrial process that extracts alumina from bauxite using caustic soda. It produces the purified alumina fed into aluminum smelters.
Corundum: The crystalline mineral form of α-alumina, with a hexagonal close-packed oxygen lattice. This stable crystal structure underlies many dense alumina ceramics.
Aluminum oxide: The inorganic compound Al₂O₃, composed of aluminum and oxygen. Aluminum oxide is the chemical name for the material called alumina.
Zirconia: Zirconium dioxide, a ceramic oxide known for toughness and oxygen-ion conductivity. Zirconia can resist crack growth better, while alumina is generally harder and cheaper.
Hall–Héroult process: An electrolytic process that reduces dissolved alumina to molten aluminum. It turns alumina into metal by electrolysis in molten cryolite.
Aluminum oxide polymorphs: Distinct crystal structures formed by aluminum oxide, including corundum and transition aluminas. Different alumina phases have different surface areas, stability, and uses.
Bauxite: A heterogeneous sedimentary rock and the principal ore of aluminum. Bauxite is the main raw material from which alumina is refined.
Silicon carbide: A hard ceramic compound of silicon and carbon used in abrasives and high-temperature devices. It competes with alumina abrasives and performs better in some high-temperature applications.
Alumina refining: The industrial purification of aluminum-bearing ores into aluminum oxide. This is the production stage that separates alumina from bauxite impurities.
Transition alumina: A family of metastable aluminum oxide phases formed before conversion to corundum. These porous phases are especially useful as catalyst supports and adsorbents.

Linked from 19 pages