ELECTROCHEMICAL CHARACTERIZATION OF LEAD-CALCIUM ALLOY IN AGITATED ZINC ELECTROWINNING ELECTROLYTE

摘要

Degradation of lead anodes has always been a major concern among the electrowinning industries. In this study, the effect of agitation of the zinc electrowinning solution on the integrity of lead anodes was investigated. Galvanostatic experiments were performed at 37±0.5℃ using 0,600 and 1000rpm magnetic stirring rates for 24 hours. The PbO_2 layer formed on the anode surface was reduced to PbSO_4 (discharged). The discharge information was used to calculate the amount of PbO_2 present on the surface. Weight loss measurements along with the discharge calculations revealed that the degradation rate of the lead anode increased as the solution was stirred more vigorously. Furthermore, the amount of remaining PbO_2 on the surfaces was decreased as a function of solution velocity. Therefore, it may be concluded that, degradation rate of lead anodes is controlled by detachment of the corrosion products from the surface rather than by electrochemical reactions.