ELECTROLYTIC EXTRACTION OF GALLIUM FROM ALKALI METAL ALUMINATE INCLUDING TWO-STAGE CARBONATATION

摘要

Abstract of the DisclosureAlkali metal aluminate solutions are subjectedto two-stage carbonatation with stirring to produce alum-inium hydroxide, a gallium-containing precipitate, andsolutions containing caustic and alkali metal bicarbonate.Thereafter the produced gallium-containing precipitate ismixed with a solution containing caustic alkali until thecontent of gallium in the solution is 0.05 to 1 g/l. Anyprecipitate formed is separated and the solution enrichedwith gallium is mixed with a solution containing alkali metalbicarbonate. The resulting mixture is subjected to evapora-tion to separate alkali metal compounds, and the solutionwhich has been subjected to evaporation is carbonated toproduce a solution containing alkali metal salts, and agallium concentrate from which gallium is produced by trans-forming it into an alkaline solution from which metallicgallium is recovered, either electrochemically, such as byelectrolysis, or by reduction with an aluminium-containinggallium alloy. The proposed method makes it possible toextract gallium at a comparatively low cost from solutionsobtained in the processing, for example, of nephelines containingit in amounts which do not exceed 0.02 to 0.03 g/l. As a resultof the proposed method, it has become possible in the processesof concentration of gallium to produce a number of valuablecomponents such as alkali metal salts contained in the startingore.