Aluminum

Aluminum

Aluminum is the second most abundant element in the Earth’s crust. It has a concentration of about 8.2 percent (Craig et al 264). Aluminum “is malleable, ductile, and easily machined and cast; and has excellent corrosion resistance and durability” (http://minerals.usgs.gov/). It is evident in everyday life.

Aluminum is a very useful abundant metal. A large fraction of the mineral products we seek are metals, such as aluminum (Halleck, 1/20). The major uses of aluminum are transportation, packaging and containers, and building products. Some other uses are electrical and consumer durable goods (Craig et al 266). It is important in the use of transportation because it is lightweight, which enables more efficient use of fuels, and it is resistant to corrosion (Craig et al 266).

“Commercially pure aluminum is comparatively soft and ductile…it has tensile strength of 13,000 pounds per square inch” when it is in its annealed condition (Hobbs 76). When the metal is strain hardened, its tensile strength is 24,000 pounds per square inch (Hobbs 76). The tensile strength can increase even more when other elements are added to the metal to form alloys. Some of these elements used for alloying are copper, iron, silicon, magnesium, nickel, and zinc (Hobbs 79).

Aluminum is also common in minerals such as feldspar, mica, which are silicates, and clay. Most of aluminum production has been from bauxite. “Bauxite can form from the weathering of any rock that is aluminum bearing” (Craig et al 267).

Most bauxite mining is done in tropical regions where there is not an abundant amount of cheap electricity or large markets for the aluminum production (Craig et al 268). The bauxite is crushed, washed, dried, and then shipped to processing sites. Aluminum is produced by the “electrolytic reduction of alumina in a molten bath of natural or synthetic cryolite” (Craig et al 268). This process is very energy intensive so it is done in areas where electricity is cheap.

“Aluminum recovery from scrap (recycling) has become an important component of the aluminum industry” (http://minerals.usgs.gov/). About thirty percent of aluminum is recycled each year. Sixty percent of that is from new scrap and forty percent is from old scrap (http://minerals.usgs.gov/). Some examples of recyclable aluminum are automobiles, windows and doors, appliances, and cans.

Aluminum is also used in many cooking utensils, electrical conductors, buildings, and in transportation industries.