(Chemical symbol: Al). Aluminum is a silver-white, malleable, ductile, light, metallic element with good electrical and thermal conductivity, high reflectivity, and resistance to oxidation. Atomic weight, 26.97; melting point, 660°C (1220°F); specific gravity, 2.70 at 20°C (68°F). Aluminum is one of the most abundant constituents of the earth’s crust. It is found in most clays, soils and rocks, but the principal commercial source is the ore, bauxite, an impure hydrated oxide. The impurities are removed from bauxite by a chemical process leaving pure aluminum oxide, alumina. Pure metallic aluminum is obtained by electrolysis of the oxide.

Aluminum is third on the scale of malleability and fifth in ductility. It is only slightly magnetic and is strongly electro-positive, so that when in contact with most metals it corrodes rapidly.

Aluminum will take a high polish, but it is likely to become “frosted” in appearance due to the formation of an oxide coating. Its electrical conductivity is about 60% that of copper. Aluminum is used extensively as a deoxidizer in steel production, and as such it is an effective purifier. Aluminum lessens grain growth by forming dispersed oxides or nitrides.