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The Bayer process is the principal industrial means of refining bauxite to produce alumina (aluminium oxide) and was developed by Carl Josef Bayer.Bauxite, the most important ore of aluminium, contains only 30–60% aluminium oxide (Al 2 O 3), the rest being a mixture of silica, various iron oxides, and titanium dioxide. [1]
Bauxite is the main source of the rare metal gallium. [17] During the processing of bauxite to alumina in the Bayer process, gallium accumulates in the sodium hydroxide liquor. From this it can be extracted by a variety of methods. The most recent is the use of ion-exchange resin. [18]
The Hall-Héroult electrolysis process is the major production route for primary aluminium. An electrolytic cell is made of a steel shell with a series of insulating linings of refractory materials. The cell consists of a brick-lined outer steel shell as a container and support. Inside the shell, cathode blocks are cemented together by ramming ...
Bauxite was discovered in 1821 by Pierre Berthier who named it after a village named Les Beaux where he found it. [6] To obtain the alumina from the bauxite ore, a process was developed that used acid to dissolve aluminium but resulted in a product that contained large amounts of iron and titanium dissolved within which were difficult to remove. [6]
Bauxite forms by the weathering of aluminum-rich and silica-poor rocks in hot, humid, climates, at places with good drainage. Under the proper conditions, weathering disintegrates the aluminium silicate minerals, and dissolves and removes the silica, creating bauxite. The mined US bauxite deposits have all been in the southeastern United States.
The US imported nearly all the bauxite (the only commercial aluminum ore) used in producing primary aluminum. For years, the US has produced less than 1% of the bauxite used to make aluminum. The US also imported 33 percent of the aluminum that was used in 2014. Of the imported aluminum, 63% came from Canada. [1] [19]
The liquid aluminium is removed from the cell via a siphon every 1 to 3 days in order to avoid having to use extremely high temperature valves and pumps. Alumina is added to the cells as the aluminum is removed. Collected aluminium from different cells in a factory is finally melted together to ensure uniform product and made into metal sheets.
Aluminium oxide (or aluminium(III) oxide) is a chemical compound of aluminium and oxygen with the chemical formula Al 2 O 3. It is the most commonly occurring of several aluminium oxides, and specifically identified as aluminium oxide. It is commonly called alumina and may also be called aloxide, aloxite, or alundum in various forms and ...