the power-generating industry to build generators large enough for the needs of an aluminum refinery. Thus aluminum became known in part as the metal of the 20th century, as iron was the metal of the 19th century. Aluminum is essential to many kinds of manufacturing, but making it from bauxite ore requires a great deal of expensive energy. In countries that refine aluminum, one-hundredth of all electricity made by power plants may be used to run the refineries. But once aluminum has been refined and used, it can be melted down and recycled using one-twentieth of the energy it took to make it in the first place. (Bowman, 392) By saving this amount of energy, not only can resources like coal and oil be saved, but less acid rain gases such as sulfur and nitrogen oxides are released in the atmosphere refining and mining for aluminum. For all these reasons it makes sense to recycle. Today, recycling now accounts for about one-half of the total aluminum. Still much energy is wasted mining for aluminum, which could be significantly reduced if more aluminum were recycled. American consumers and industries alone throw away enough aluminum to rebuild the entire U.S. commercial air fleet every three months. (Aluminum Facts) Although it is so widely used, aluminum has only recently come into use. Unlike gold and silver, aluminum is never found uncombined in nature. It is always chemically combined with other elements. People had no way of separating aluminum from these elements until the 1800's. (Walker, 31) A large reason why aluminum is never found uncombined in nature is because it is so strongly attracted to oxygen. (Knapp, 4, 5) Aluminum is a reactive metal. When exposed to the air, it immediately develops an oxide coating that prevents further corrosion. However, along with a few other metals, aluminum compounds can be dissolved by both acids and alkalis. Metal compounds with this special property are called amphoteric metals. This property h...
