Innovative Solvent Extraction Processes for the Separation of Indium, Germanium, and Gallium from Iron

Germanium, gallium, and indium are valuable elements due to their great economic importance and growing utilization in high-tech and green-tech applications. The exploitation of secondary resources, for example, tailings, slags, or end-of-life products, as well as the application of sustainable biotechnological methods, results in the challenge of separating Fe(III) from In(III), Ge(IV), or Ga(III). With common methods, such as precipitation, the selectivity for In, Ga, and Ge is often insufficient. The application of innovative solvent extraction processes is a promising approach to separate valuable metals from iron in order to make them available for an efficient recovery. In this study, we present the development of extraction methods using amine extractants for the selective separation of Fe(III) from In(III), Ga(III), and Ge(IV) in sulphate solutions. The influence of different parameters, e.g. the pH value and the composition of the organic phase, as well as possibilities to re-extract iron from the loaded organic phase, will be discussed.