Abstract:In the process of hydrometallurgy of zinc, copper and cadmium in the solution of zinc sulfate are replaced by zinc powder, and vacuum distillation is an important process for comprehensive recovery and utilization of high cadmium slag. In this paper, the modified molecular interaction volume model (M-MIVM) is used to predict the activity of Cd-Cu-Zn alloy, and on this basis, the vapor-liquid equilibrium of Cd-Cu-Zn alloy during vacuum distillation is predicted. The results show that the total average standard deviation of M-MIVM is 0.0037 in the comparison between the experimental value of activity in the binary alloy and the calculated value of the model, which has better accuracy and stability than the traditional local composition model. This study can provide more accurate basic thermodynamic data for the production of high-purity cadmium and the comprehensive recovery and utilization of crude cadmium; at the same time, it also provides a theoretical basis for predicting the vapor-liquid equilibrium calculation of vacuum distillation.