PROCESS FOR LIQUID-LIQUID EXTRACTION OF GALLIUM FROM BASIC AQUEOUS SOLUTIONS BY MEANS OF AN ORGANIC EXTRACTION AGENT

摘要

Process for the liquid-liquid extraction of gallium from basic aqueous solutions, particularly sodium aluminate lye from alumina production according to the Bayer process, by means of an organic extraction agent comprised of a solvent and of substituted hydroxyquinoline, aluminium in addition to gallium being in the organic extraction agent solution. In five successive steps, the organic extraction agent solution containing gallium and aluminium is brought in substance exchange relationship with an aqueous mineral acid solution; the latter lades itself with gallium and aluminium and separates from the organic extraction agent solution. Chloride salt or hydrochloric acid is then dissolved into the solution laden with gallium and aluminium and is placed in substance exchange relationship with an organic solvent, for example an n-butyl acetate solution. The aluminium then remains in the aqueous acid solution while the organic solvent lades itself with gallium. After separation of the aqueous acid solution, the organic solvent is separated from the gallium chloride which is the starting product for the production of pure gallium. A main advantage of the present process is that, in the third step, the aqueous concentrated mineral acid laden with gallium and aluminium may be placed in substance exchange relationship with an organic solvent which, besides the fact that it is less costly, may be more gallium laden than substituted hydroxyquinoline.