Aluminium is the third most abundant element in the earth’s crust, surpassed in abundance only by oxygen and silicon, yet it is a comparatively new industrial metal that has been produced in commercial quantities for just little over 100 years. It weighs about one-third as much as steel or copper; is malleable, ductile, and easily machined and cast; and has excellent corrosion resistance and durability.
Although it comprises about 8 percent of the earth’s crust, it is not found free in nature, but always in combination with other elements. Bauxite, which is a rock that consists of one or more Aluminium hydroxide minerals, is the principal raw material used by the Aluminium industry for the production of Aluminium metal. The types of bauxite used are Trihydrate, which consists chiefly of gibbsite, monohydrate, which consists mainly of Boehmite, and mixed bauxite, which consists of gibbsite and Boehmite. Bauxite deposits have formed chiefly by the weathering of aluminous rock; some have been transported to their present locations, but most are residual accumulations from which most constituents of the parent rock, other than alumina have been leached. Conditions favorable for the formation of bauxite are warm tropical climate, abundant rainfall, aluminous parent rocks that have high permeability and good subsurface drainage and long periods of tectonic stability that permit deep weathering and preservation of land surfaces.
Aluminium production is a global industry. Bauxite ore is mined in locations such as Australia, China, and Africa. Alumina plants operate across the world, including in Russia and Eastern Europe. Aluminium products are produced and shipped globally. The international Aluminium industry creates careers in finance, operations, IT, and management around the world.
Most bauxite ores are mined by open pit methods, and treatment at the mine site is usually confined to crushing, washing, and drying operations. Ore that is transported appreciable distances is often dried before shipment, which can result in savings in shipping costs that will more than offset the drying costs. The degree to which a specific bauxite is dried depends in part on its handling and dusting haracteristics.
Aluminium recovery from scrap (recycling) has become an important component of the Aluminium industry. A common practice since the early 1900s, Aluminium recycling is not new. It was, however, a low-profile activity until the late 1960s when recycling of Aluminium beverage cans finally vaulted recycling into the public consciousness. Sources for recycled Aluminium include automobiles, windows and doors, appliances, and other products. However, it is the recycling of Aluminium cans that seems to have the highest profile.