Optimization of Zinc and Germanium Recovery Process from Zinc Oxide Dust by Response Surface Methodology

Abstract

Based on the problems existing in the existing process, the ultrasonic field enhanced potassium dichromate atmospheric leaching of zinc and germanium in zinc oxide dust was studied, and three main factors (liquid‐solid ratio, leaching temperature and potassium dichromate concentration) were optimized by the Box‐Behnken design (BBD) model. XRD, ICP‐OES, EPMA and SEM results show that the occurrence state of Ge is highly correlated with ZnS. Promoting the dissolution of ZnS is the basis for improving the leaching rates of Zn and Ge. Finally, under the conditions of liquid‐solid ratio of 7 mL/g, leaching temperature of 90 °C and potassium dichromate concentration of 19.16 g/L, the leaching rates of zinc and germanium were 99.968 % and 90.395 %, respectively. The error between the prediction results of the quadratic model and the experimental results is small, and the correlation coefficients are greater than 0.99, indicating that the model is credible.