Process for extracting and purifying gallium from bayer liquors
AssigneeAluminium Pechiney B.P.
InventorJean-Michel Lamerant
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Abstract
A process for extracting and purifying the gallium contained in an industrial solution of sodium aluminate by fixing the gallium on a stationary phase constituted by porous polystyrene adsorbent resin which is impregnated with an extracting agent, optionally in the presence of a surface-active agent. After elution of the gallium in acid medium, the resultant gallium salt is purified and concentrated so as to be reduced directly to the state of high purity metallic gallium, by electrolysis.
Claims28
A process for extracting and purifying gallium contained in a sodium aluminate solution, comprising the following sequence of steps:
- (a) impregnating a porous adsorbent resin with a 7-alkyl-8-hydroxyquinoline extracting agent in the presence of a volatile solvent;
- (b) evaporating said volatile solvent;
- (c) hydrating said porous adsorbent resin;
- (d) fixing gallium onto said porous adsorbent resin by passing a sodium aluminate solution taken directly from a Bayer cycle, having a precipitation stage, and kept at a temperature of between 30.degree. C. and 60.degree. C., over said porous adsorbent resin;
- (e) washing said porous adsorbent resin with water;
- (f) eluting gallium fixed onto said porous adsorbent resin with a strong mineral acid having a concentration of between 0.7 N and 7N;
- (g) performing a first purification and concentration operation of the gallium by precipitating the gallium in a reducing medium to gallium hydroxide and redissolving the gallium in the form of gallium chloride;
- (h) performing a second purification and concentration operation of the gallium by contacting the gallium chloride with an organic solution comprising tributylphosphate, a C.sub.8-13 alcohol, and an aromatic solvent, until said organic solution is saturated with gallium, and then eluting with water;
- and
- (i) subjecting to electrolysis the concentrated and purified gallium chloride solution to obtain metallic gallium.
Dependencies are inferred from the claim text.