alúmina

Alümina, also known as aluminum oxide, is a chemical compound with the formula Al2O3. It is one of the most common and widely used compounds of aluminum. Alümina is a white, crystalline solid that is insoluble in water. It is characterized by its hardness, high melting point, and electrical insulating properties. These properties make it a versatile material with numerous industrial applications.

Naturally occurring forms of alümina include minerals such as corundum, which is prized for its hardness and is used as an abrasive. Sapphire and ruby are also forms of corundum, with their distinctive colors arising from trace impurities. Industrially, alümina is primarily produced from bauxite ore through the Bayer process. This process involves extracting aluminum hydroxide, which is then calcined at high temperatures to yield pure alümina.

Alümina finds extensive use as an abrasive due to its hardness, appearing in sandpaper, grinding wheels, and polishing compounds. Its high melting point and chemical inertness make it an excellent refractory material, used in furnace linings, crucibles, and kiln furniture. In the electrical industry, alümina's insulating properties are utilized in components like spark plugs and substrates for electronic circuits. Furthermore, alümina is a key precursor in the Hall-Héroult process for producing metallic aluminum and is employed in the manufacturing of ceramics, glass, and even as a filler in plastics and paints. Its diverse applications underscore its importance in modern industry.

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