Spouted Bed Electrowinning of Zinc: Part I. Laboratory-Scale Electrowinning Experiments

This study investigates the electrowinning of zinc from sulfate electrolytes using two types of laboratory cells: one cylindrical and one rectangular geometry. The objective was to determine the performance of these configurations in terms of current efficiencies and energy consumption during zinc electrodeposition onto a spouted bed of zinc particles, with sizes ranging from 0.75 to 1.45 mm. Both cell types were operated on either industrial or synthetic electrolytes, and experiments were carried out in a batch mode. The findings revealed current densities varied between 1380 to 6200 A/m2, and the performance metrics indicated that the flat cell outperformed the cylindrical one, achieving energy consumptions under 3 kWh/kg zinc at current densities up to 3500 A/m2. Current efficiencies for the flat cell application reached 91 to 92 percent when reducing zinc content from 150 to 100 g/L. Overall, the results demonstrate significant advancements in current efficiency compared to previous studies, highlighting the effectiveness of the spouted bed design in optimizing zinc electrowinning processes.