A Study on the Application Characteristics of the Insoluble MMO (Mixed Metal Oxide) Electrode for Energy Reduction of Zinc Electrowinning Process

Abstract

Objective : The zinc electrowinning industry is one of the high energy consumption industries where energy saving is required. In the zinc electrowining process, electrode is a high energy consuming part. In order to reduce energy use in the electrolytic smelting industry, a comparative study was conducted on the current usage of Pb+Ag alloy electrode and insoluble composite metal oxide (MMO) electrode.Methods : In this study, a comparative evaluation of energy consumption was conducted between the generally used Pb+Ag alloy electrode and an insoluble MMO electrode. Aluminum was used as a reducing electrode. The actual on-site zinc electrowinning solution and ZnSO₄ simulated solution were prepared to estimate the electrode potential, voltage, zinc deposition efficiency, and lifetime characteristics under the current density of 500 A/m².Results and Discussion : The overvoltage of the insoluble MMO electrode was 28.9% lower and the voltage was 15.0% lower than that of Pb+Ag alloy electrode. The zinc deposition efficiency of the insoluble MMO electrode was higher 1.9% in the actual on-site zinc electrowinning solution and 6.3% in the simulated solution. Compared with the Pb+Ag alloy electrode in use, the insoluble composite metal oxide electrode exhibited low overvoltage, good voltage characteristics, and high current efficiency characteristics.Conclusions : When the energy consumption of the Pb+Ag alloy and the insoluble MMO electrodes was compared, The insoluble MMO electrode showed 17.0% lower energy consumption in the actual on-site zinc electrowinning solution and 23.8% lower in the ZnSO₄ simulated solution than Pb+Ag alloy electrode.