LIQUID-LIQUID-EXTRACTION OF GALLIUM BY TRI-N-BUTYL PHOSPHATE

The recovery of gallium from discarded germanium plant solutions by solvent extraction with tri-n-butyl phosphate (TBP) has been investigated. Because of the high content of iron, selective extraction of gallium with undiluted TBP is not possible, but suitable conditions are obtained by diluting the TBP with an aliphatic hydrocarbon and extracting at an acidity of 4 M. It is advantageous to reduce the FeIII in the initial solution to the bivalent state; scrubbing of the loaded organic phase with HCl also increases the final Ga/Fe ratio. Gallium can be recovered from the strip solution by hydrolysis, and it is again beneficial to add a reducing agent. A gallium yield of 99.5% has been obtained in a final dry product containing 50.9% Ga and 1% Fe. © 1979.