A Review on Germanium Resources and its Extraction by Hydrometallurgical Method

Resources of germanium and its extraction from the resources by hydrometallurgical methods were reviewed. Although Ge exists in some sulfide ores, by-products and residues from the processing of these ores and coal combustion are the primary resources for Ge recovery. Optical fiber and solar panel wastes can be considered as important secondary resources of Ge. Hydrometallurgical processes consisting of leaching and solution purification is recommended for the recovery of germanium from these resources. In leaching, organic acids are added to the inorganic acid solution to enhance the formation of stable anionic Ge(IV) complexes, the existence of which makes solution purification simpler. Cementation, precipitation, membrane, ion exchange, and solvent extraction were reviewed as a solution purification step for the recovery of Ge(IV) from leach liquors. Several hydrometallurgical processes for the recovery of Ge(IV) from the main germanium-bearing resources were compared in terms of process efficiency and environmental burden.