Kinetics Study on Microwave Alkaline Roasting-Water Dissolving of Germanium from Zinc Oxide Dust

Abstract Zinc hydrometallurgy plants produce large amounts of germanium (Ge)-containing zinc oxide (ZnO) dust during the production process. However, the present leaching percentages of Ge by the sulfuric leaching process from ZnO dust are generally lower than 60%. Thus, a novel process of microwave alkaline roasting followed by water dissolving is proposed to further improve Ge extraction from ZnO dust, and the kinetic behaviors and related theoretical models are studied. Perhaps it can be promoted Ge leaching percentages by water after microwave alkaline roasting, the dissolving reaction kinetics follow the diffusion control model, and the apparent activation energy is 15.46 kJ/mol.