Enhanced gallium and germanium recovery from zinc pressure leachate via zinc powder cementation

Industrial extraction of Ga and Ge from zinc concentrate has been achieved; however, their recoveries remain relatively low because of dispersion during various procedures. This study thoroughly investigated the distribution behavior and precipitation mechanism of Ga and Ge from zinc pressure leachate into refinery residue. Process mineralogical investigations demonstrated that Ga primarily precipitated through the formation of jarosite, while Ge enrichment was driven by reduction using zinc powder. Controlling the terminal acidity within the range of 6.0–7.0 g/L during pre-neutralization effectively minimized jarosite formation, thereby reducing Ga loss to below 2.0 mg/L. The cementation process was further improved by introducing secondary zinc oxide, followed by zinc powder in a sequential manner. Strategic adjustment of the pH profile—beginning at 1.9–2.1 and concluding at 3.0–3.5—led to residual Ga and Ga concentrations of less than 2.0 mg/L and 1.0 mg/L, respectively. These conditions enabled production trials to achieve recovery efficiencies above 85 % for Ga and over 96 % for Ge.