Mechanism of ultrasound enhanced selective oxygen pressure leaching of Ga and Ge from zinc powder replacement residue

The leaching mechanism of gallium (Ga) and germanium (Ge) from zinc powder replacement residue (ZPRR) was investigated through ultrasonic-assisted sulfuric acid leaching. Characterization via XRD, SEM, XPS, and FT-IR revealed that ultrasonic treatment promotes the dehydration of H 4 SiO 4 colloids, thereby reducing their adsorption capacities for Ga and Ge complexes. Additionally, ultrasound enhances the dissolution of CaS in H 2 SO 4 , increasing H 2 S production, which aids in the reduction of Fe 3+ and mitigates iron precipitate formation. Process parameters including ultrasonic power (0−450 W), temperature (100−120 °C), and leaching time (30−120 min) were systematically optimized, achieving optimal leaching efficiencies of Ga and Ge at 95.7% and 94.5%, respectively.