Charles M. Hall
In 1866, Charles M. Hall (USA) and Paul T. Heroult (France) each invented a process for the production of aluminum by the electrolysis of alumina dissolved in molten cryolite. Charles Hall, with the support of his friends, established the Pittsburgh Reduction Company which launched its first smelter in Kensington outside Pittsburgh on September18, 1888
Bauxite is a red, clay-like dirt formed over millions of years by the weathering of rocks containing aluminimum silicates. It is rich in aluminum oxide, which is eventually processed into the aluminum we see all around us today. Bauxite was first discovered in southern France in 1821 in a village known as Les Baux. The name of the geologist that discovered it was Pierre Berthier. In 1847, Armand Dufrenoy named the ore “beauxite," then in 1854, Henri Sainte-Claire Deville rename it “bauxite.”
The first country to mine Bauxite was Sierra Leone in Africa in the 1920s, long before diamond was discovered in the country.
In the nearly 170 years since aluminum was first isolated by Oersted, the metal has grown from a laboratory curiosity to a position of major importance in the world's commerce. In terms of annual production rates, aluminum is first among non-ferrous metals.
Oersted's discovery, the reduction of aluminum chloride with potassium amalgam, was improved on by St. Claire Deville. Deville's sodium amalgam reduction of aluminum chloride led to the commercial production of aluminum in France in 1855. In 1866, Charles M. Hall (USA) and Paul T. Heroult (France) each invented a process for the production of aluminum by the electrolysis of alumina dissolved in molten cryolite.
In 1888, Karl Joseph Bayer patented his process which used a seed of alumina hydrate to precipitate additional alumina hydrate. This improved the crystallinity and purity of the product and made it more easily filtered and washed. In 1894, he filed his second patent covering the extraction of alumina from bauxite in caustic soda solution under pressure by the formation of a sodium aluminate solution. Furthermore, the spent liquor from precipitation could be recirculated to extract more alumina from bauxite.
The basic process developed by Bayer, which remains essentially unchanged to this time, led to the economical recovery of alumina from bauxite. With alumina readily available, the production of the metal and its uses have expanded over the years to their current level.
The Pittsburgh Reduction Company
The Pittsburgh Reduction Company built new smelters in New York State near the new Niagara hydroelectric power station. It produced only 20-25 kg of aluminum per day in the first few months, but quickly accelerated to 240 kg daily by 1890.
The Pittsburgh Reduction Company was reorganized into the Aluminum Company of America, or more commonly known, Alcoa in 1907.