alpha alumina is used for which purpose?

Answer 1

USED FOR MAKING GEMSTONES LIKE RUBY ,EMERGLAD etc. its prepared by heating Al(OH)3 above 1300k

Answer 2

What Is Alumina Used For

Answer 3

Alumina is commercially important. A major use is in the production of aluminum metal. It is also used for abrasives; corundum and emery are widely used, as are artificially prepared alumina abrasives. Trade names for alumina abrasives include Alundum and Aloxite. Alumina is also used in ceramics, in pigments, and in the manufacture of chemicals. Clays containing alumina are used in porcelain, pottery, and bricks. Pure alumina is used in making crucibles and other refractory apparatus. Hydrated alumina is used in mordant dyeing to make lake pigments; it is also used in glassmaking, in cosmetics, and in medicine as an antacid.

Answer 4

Alumina occurs in two crystalline forms. Alpha alumina is composed of colorless hexagonal crystals with the properties given above; gamma alumina is composed of minute colorless cubic crystals with sp. gr. about 3.6 that are transformed to the alpha form at high temperatures.

Thermal conductivity, high-temperature load-bearing resistance, reheat shrinkage, and porosity were determined on new pure oxide heavy refractories of alumina, magnesia, and stabilized zirconia. Alumina refractories were shown to be capable of lining furnaces for operation to 1900 °C, and magnesia and stabilized zirconia refractories to at least 2300 °C. The thermal conductivity of alumina refractories was found to vary directly with density, and four mixtures are described with conductivities ranging from 6 to 18 B.t.u. per hr. per sq. ft. per in. per °F. at 1800°F. Stabilized zirconia refractories, although having twice the bulk density of fire-clay brick, showed lower thermal conductivity. The uses and limitations of pure oxide heavy refractories are discussed.