History of Aluminium
Although Aluminium is the most abundant metal in the earth's crust, it is never found free in nature. All of the earth's Aluminium has combined with other elements to form compounds. Two of the most common compounds are alum, such as potassium, Aluminium sulfate (KAl (SO4)2•12H2O), and Aluminium oxide (Al2O3). About 8.2% of the earth's crust is composed of Aluminium.
The ancient Greeks and Romans used alum in medicine as an astringent, and in dyeing processes. In 1761 de Morveau proposed the name "alumine" for the base in alum. In 1807, Davy proposed the name aluminium for the metal, undiscovered at that time, and later agreed to change it to Aluminium. Shortly thereafter, the name aluminium was adopted by IUPAC to conform to the "ium" ending of most elements. Aluminium is the IUPAC spelling and therefore the international standard. Aluminium was also the accepted spelling in the U.S.A. until 1925, at which time the American Chemical Society decided to revert back to Aluminum, and to this day Americans still refer to Aluminium as "Aluminum".
Aluminium is one of the elements which as alum or alumen, KAl(SO4)2, has an alchemical symbol (the symbol to the right alchemical symbol of alum (alumen) shows Scheele's symbol, alchemy is an ancient pursuit concerned with, for instance, the transformation of other metals into gold).
Aluminium was first isolated by Hans Christian Oersted in 1825 who reacted aluminium chloride (AlCl3) with potassium amalgam (an alloy of potassium and mercury). Heating the resulting aluminium amalgam under reduced pressure caused the mercury to boil away leaving an impure sample of aluminium metal.
Scientists suspected than an unknown metal existed in alum as early as 1787, but they did not have a way to extract it until 1825. Hans Christian Oersted, a Danish chemist, was the first to produce tiny amounts of Aluminium. Two years later, Friedrich Wöhler, a German chemist, developed a different way to obtain Aluminium. By 1845, he was able to produce samples large enough to determine some of Aluminium basic properties. Wöhler's method was improved in 1854 by Henri Étienne Sainte-Claire Deville, a French chemist. Deville's process allowed for the commercial production of Aluminium. As a result, the price of Aluminium dropped from around $1200 per kilogram in 1852 to around $40 per kilogram in 1859. Unfortunately, Aluminium remained too expensive to be widely used.
Two important developments in the 1880s greatly increased the availability of Aluminium. The first was the invention of a new process for obtaining Aluminium from Aluminium oxide. Charles Martin Hall, an American chemist, and Paul L. T. Héroult, a French chemist, each invented this process independently in 1886. The second was the invention of a new process that could cheaply obtain Aluminium oxide from bauxite. Bauxite is an ore that contains a large amount of Aluminium hydroxide (Al2O3•3H2O), along with other compounds. Karl Joseph Bayer, an Austrian chemist, developed this process in 1888. The Hall-Héroult and Bayer processes are still used today to produce nearly all of the world's Aluminium.
With an easy way to extract Aluminium from Aluminium oxide and an easy way to extract large amounts of Aluminium oxide from bauxite, the era of inexpensive Aluminium had begun. In 1888, Hall formed the Pittsburgh Reduction Company, which is now known as the Aluminium Company of America, or Alcoa. When it opened, his company could produce about 25 kilograms of Aluminium a day. By 1909, his company was producing about 41,000 kilograms of Aluminium a day. As a result of this huge increase of supply, the price of Aluminium fell rapidly to about $0.60 per kilogram.
Today, Aluminium and Aluminium alloys are used in a wide variety of products: cans, foils and kitchen utensils, as well as parts of airplanes, rockets and other items that require a strong, light material. Although it doesn't conduct electricity as well as copper, it is used in electrical transmission lines because of its light weight. It can be deposited on the surface of glass to make mirrors, where a thin layer of Aluminium oxide quickly forms that acts as a protective coating. Aluminium oxide is also used to make synthetic rubies and sapphires for lasers.