Recovery of gallium(III) from strongly alkaline media using a Kelex-100-loaded ion-exchange resin

Kelex-100 [7-(4-ethyl-1-methyloctyl)-8-hydroxyquinoline] is an important liquid-chelating ion exchanger in hydrometallurgy and a highly selective extractant for gallium(Ga). In this study, Kelex-100-loaded ion-exchange resins were prepared for the recovery of Ga(III) from sodium aluminate solutions (Bayer solution) used in the Bayer process. When macroporous type ion-exchange resins were used as polymer matrices for loading Kelex-100, the physical pore structure and the ion-exchange group significantly affected the adsorption of Ga(III) from strongly alkaline media on the Kelex-100-loaded resin. In particular, the Kelex-100-loaded carboxylic type resin having a macroporous structure showed a high capacity for Ga(III) in concentrated NaOH solution and effectively recovered Ga(III) from the Bayer solution containing large amounts of aluminum(III).