Deville-Pechiney
Deville-Pechiney : An obsolete process for making alumina from bauxite. Bauxite was roasted with sodium carbonate, yielding sodium aluminate: Al2O3 + Na2CO3 + 2NaAlO2 + CO2 The product was digested with warm water, which dissolved the sodium aluminate and left the other materials as an insoluble residue. Passage of carbon dioxide through the clarified liquor precipitated aluminum as hydroxide: 2NaAlO2 + CO2 + 3H2O + 2Al(OH)3 + Na2CO3 All the silica present in the bauxite was converted to insoluble sodium aluminosilicate, which represented a loss of sodium and aluminum. The aluminum hydroxide was calcined to the oxide, and the sodium carbonate solution was concentrated for re-use. (Check source for accuracy of chemical formula)
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