Highly selective removal of Ga³⁺ ions from Al³⁺/Ga³⁺ mixtures using graphite oxide

In this paper, we present a simple solution to a major technological issue, the extraction of gallium from bauxite ore and aluminium-gallium separation. Due to its extremely large surface area and oxygen functional groups, graphite oxide was used for the highly selective sorption of Ga³⁺ from Al³⁺/Ga³⁺ mixtures. Graphite oxide prepared according to the Hummers method has various oxygen functionalities which form coordination bonds with metal ions. Sorption capacity and selectivity of graphite oxide towards Al³⁺, Ga³⁺ and their mixtures were investigated. Since the results of these experiments revealed much higher affinity of graphite oxide to Ga³⁺ ions, we tested the procedure on aluminium-gallium oxide prepared by Bayer process from real bauxite ore. In this case too, the results showed that Ga³⁺ accumulated on the graphite oxide surface. This suggests that high sorption selectivity can be used for the extraction of gallium on an industrial scale and, thus, as a rich source of gallium for the semiconductor industry.