Process for producing metallic gallium

Abstract

A highly efficient process for producing metallic gallium from a gallium containing alkali aluminate solution circulating in the Bayer process is disclosed. The process comprises subjecting an alkali aluminate solution to electrolysis, said solution being obtained by (1) cooling an alkali aluminate solution after the aluminum hydroxide separation step in the Bayer process in the presence or absence of at least one, as a seed, alkali salt of an element selected from vanadium and phosphorus, or complexes containing the alkali salt, in order to precipitate crystals of impurities containing vanadium, phosphorus, etc. in the solution; removing the precipitates; and then subjecting the resulting alkali aluminate solution to oxidation treatment; or by (2) subjecting an alkali aluminate solution after the aluminum hydroxide separation step in the Bayer process to oxidation treatment; cooling the resulting liquor in the presence or absence of at least one, as a seed, alkali salt of an element selected from vanadium and phosphorus, or complexes containing the alkali salt, in order to precipitate crystals of impurities containing vanadium, phosphorus, etc. in the liquor; and then removing the precipitates.