Magnesium was first purified in 1808 by the English scientist Davy but it was not until 1923 that a satisfactory extraction process was identified. Since then the output of pure magnesium has grown from 2,500 tonnes in 1930 to 350,000 tonnes worldwide in 1990.
Magnesium is the 8th most abundent element and constitutes about 2% of the Earth's crust, and it is the third most plentiful element dissolved in seawater. Although magnesium is found in over 60 minerals, only dolomite, magnesite, brucite, carnallite, and olivine are of commercial importance. Magnesium and other magnesium compounds are also produced from seawater, well and lake brines and bitterns. Magnesium compounds, primarily magnesium oxide, are used mainly as refractory material in furnace linings for producing iron and steel, nonferrous metals, glass, and cement. Magnesium oxide and other compounds also are used in agricultural, chemical, and construction industries. Magnesium metal's principal use is as an alloying addition to aluminum, and these aluminum-magnesium alloys are used mainly for beverage cans. Magnesium alloys also are used as structural components of automobiles and machinery. Magnesium also is used to remove sulfur from iron and steel.