The Deville process was the first industrial process used to produce
alumina from
bauxite
Bauxite is a sedimentary rock with a relatively high aluminium content. It is the world's main source of aluminium and gallium. Bauxite consists mostly of the aluminium minerals gibbsite (Al(OH)3), boehmite (γ-AlO(OH)) and diaspore (α-AlO(O ...
.
The Frenchman
Henri Sainte-Claire Deville
Henri is an Estonian, Finnish, French, German and Luxembourgish form of the masculine given name Henry.
People with this given name
; French noblemen
:'' See the 'List of rulers named Henry' for Kings of France named Henri.''
* Henri I de Mont ...
invented the process in 1859. It is sometimes called the Deville-
Pechiney
Pechiney SA was a major aluminium conglomerate based in France. The company was acquired in 2003 by the Alcan Corporation, headquartered in Canada. In 2007, Alcan itself was taken over by mining giant Rio Tinto Alcan.
Prior to its acquisition ...
process.
It is based on the extraction of alumina with
sodium carbonate.
The first stage is the calcination of the bauxite at 1200 °C with
sodium carbonate and
coke. The alumina is converted in
sodium aluminate. Iron oxide remains unchanged and silica forms a polysilicate.
In the second stage
sodium hydroxide
Sodium hydroxide, also known as lye and caustic soda, is an inorganic compound with the formula NaOH. It is a white solid ionic compound consisting of sodium cations and hydroxide anions .
Sodium hydroxide is a highly caustic base and alkal ...
solution is added, which dissolves the sodium aluminate, leaving the impurities as a solid residue. The amount of sodium hydroxide solution needed depends upon the amount of silica present in the raw material. The solution is filtered off;
carbon dioxide
Carbon dioxide ( chemical formula ) is a chemical compound made up of molecules that each have one carbon atom covalently double bonded to two oxygen atoms. It is found in the gas state at room temperature. In the air, carbon dioxide is t ...
is bubbled through the solution, causing
aluminium hydroxide
Aluminium hydroxide, Al(OH)3, is found in nature as the mineral gibbsite (also known as hydrargillite) and its three much rarer Polymorphism (materials science), polymorphs: bayerite, doyleite, and nordstrandite. Aluminium hydroxide is Amphoter ...
to
precipitate
In an aqueous solution, precipitation is the process of transforming a dissolved substance into an insoluble solid from a super-saturated solution. The solid formed is called the precipitate. In case of an inorganic chemical reaction leading ...
, leaving a solution of sodium carbonate. The latter can be recovered and reused in the first stage.
The aluminium hydroxide is
calcined to produce alumina.
The process was used in France at
Salindres until 1923 and in Germany and Great Britain until the outbreak of the Second World War.
It has now been replaced by the
Bayer process
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 (Al2O3), th ...
.
Further reading
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See also
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Bayer process
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 (Al2O3), th ...
*
History of aluminium
Aluminium (or aluminum) metal is very rare in native form, and the process to refine it from ores is complex, so for most of human history it was unknown. However, the compound alum has been known since the 5th century BCE and was used extensive ...
*
Orbite process
References
{{reflist
Translated from the French Wikipedia article "Extraction de l'alumine".
Industrial processes
Aluminium industry
fr:Extraction de l'alumine