Abstract
| Using mixed metal oxide (MMO) anodes in zinc electrowinning is highly desirable as it represents potential to significantly reduce electrical energy consumption. However, the major challenge for implementing this type of anode in zinc cell houses is the presence of manganese in the electrolyte, which could deposit on the electrocatalytic surface of the MMO anode and deactivate it. Therefore, it is crucial to reduce manganese concentration in the zinc electrowinning process when using MMO anodes. This study aims to remove manganese from a zinc-rich solution by using an oxidative precipitation method with an SO2/air gas mixture and the catalytic effect of cobalt. In this study, we investigated the effect of various operating parameters, such as the SO2/air ratio, reaction time, and cobalt concentration, on the Mn removal efficiency and characterized the precipitates. During the reaction, the pH is controlled by adding calcium hydroxide. The results show that adding 10 mg/L of cobalt to the solution significantly accelerates manganese removal kinetics, reducing the manganese concentration from 1 g/L to less than 1 mg/L within 30 minutes. In addition, the manganese elimination process also reduces cobalt ion concentration from 10 mg/L to 1 mg/L. The morphology of the manganese dioxide changes from an angular pebble-like to a cauliflower-like shape due to the addition of calcium hydroxide, as observed in SEM pictures. |
Keywords
Manganese oxidative precipitation, SO2/air gas mixture, MMO anodes, Catalytic effect of cobalt
