Study on the Sulfuric-Leaching Kinetics of Germanium from Zinc Oxide Dust Assisted by Microwave Roasting

Abstract The Ge-bearing zinc oxide dust (ZnO) is commonly leached by sulfuric acid in industry, but the leaching percentage of Ge is only < 60%. To date, there is no suitable industrial process to address this problem. Thus, a novel process of microwave roasting followed by sulfuric acid leaching of Ge from ZnO dust is proposed to further improve Ge extraction from ZnO dust, and the kinetics behaviors and related theoretical models are studied. Results reveal that Ge leaching percentages are markedly increased by microwave roasting, the reaction kinetics follow the shrinking core model of the diffusion process of the solid film, and the apparent activation energy is 2.28 kJ/mol.