Sumitomo Aluminium Smelting Company, Ltd.

Sumitomo Chemical Company, Limited

Yasuo Shinya

Koichi Yamada

Takuo Harato

Hisakatsu Kato

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.

Process for producing metallic gallium

A method is provided for producing a sintered zirconia article excellent in thermal shock resistance and high in sintered density. The method comprises mixing zirconia powder as the starting material and a stabilizing agent with a definite amount of partially stabilized zirconia powder, shaping and sintering the mixture, and heat treating it under specific temperature conditions.

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Niihama, Japan

Yasuo Shinya