aluminium

American Heritage® Dictionary of the English Language, Fourth Edition

1. n. Chiefly British Variant of aluminum.

Century Dictionary and Cyclopedia

1. n. Chemical symbol Al; atomic weight 27.1. A metal of silver-white color and brilliant luster, about as hard as zinc, very malleable and ductile, highly sonorous, and a good conductor of heat and electricity. Its most remarkable character is its low specific gravity (2.56), which is about one third that of iron and less than that of marble. It does not tarnish in the air, and even in a molten state does not oxidize; its melting-point is somewhat lower than that of silver. Aluminium in combination with oxygen (Al₂O₃) forms the common earth alumina, which exists in nature as the mineral corundum, of which the ruby, sapphire, and emery are varieties; the hydrated sesquioxid exists as the minerals diaspore, gibbsite, and bauxite. Alumina also enters into the composition of a very large number of minerals, the most important of which are the feldspars. From the decomposition of these, clay (kaolin, etc.) is produced, which is essentially a hydrated silicate of aluminium. Among other important minerals containing aluminium are the silicates andalusite, cyanite. fibrolite, topaz, and all of the zeolites; the fluoride of aluminium and sodium, cryolite, from which the metal is reduced; the oxid of aluminium and magnesium, spinel; the sulphates aluminite, alum-stone, the alums, etc.; the phosphates turquoise, lazulite, etc.; the carbonate dawsonite, and many others. It is estimated that in its various compounds aluminium forms about one twelfth of the crust of the earth. In consequence of its very low specific gravity, freedom from tarnish, non-poisonous qualities, and ease of working, aluminium is a most valuable metal, and would be extensively used if it were not for the cost of separating it from the combinations in which it occurs in nature. It is used, however, to a limited extent by itself and in alloys for physical apparatus and other articles in which lightness and great strength are necessary. The cap of the Washington monument, which forms the tip of its lightning-rod, is a pyramidal mass of aluminium weighing 100 ounces. Also written aluminum.
2. n. Aluminium melts at 654.5° C., and the tensile strength of bars made of it is about 28,000 pounds a square inch. The commercial production of the metal began about 1888, the process most largely used, as at Pittsburg and Niagara, being that of Hall, in which anhydrous alumina from bauxite is dissolved in a bath of fused cryolite in the presence of carbon and electrolyzed by a current of 6 or 7 volts and 7,000 amperes. The price has been brought down from $15 to 30 cents a pound, and the annual output increased from 3 to many thousand tons per annum. The only moderate strength of the metal, certain difficulties in working it (as, for instance, in soldering), and its chemical alterability under some conditions have tended to limit its applications. Among the more recent uses made of it may be mentioned the etching of designs for theatrical and other posters, substitution for copper in wire for the transmission of electric currents, the manufacture of a silver-like paint from the powder, and the production of a very high temperature by rapid combustion of the powder in admixture with sodium dioxid. See aluminothermics.

Wiktionary

1. n. A light, silvery metal extracted from bauxite, and a chemical element (symbol Al) with an atomic number of 13.

GNU Webster's 1913

1. n. (Chem.) same as aluminum, chiefly British in usage.

WordNet 3.0

1. n. a silvery ductile metallic element found primarily in bauxite