Replacement of lead-silver anodes with Ti-based anodes in zinc electrowinning process: (feasibility, coating developement, side effects, performance and energy efficiency)

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This research and development program aims to improve the energy efficiency of the zinc electrolysis process. Two industrial partners support this research program; CEZinc and Outotec Canada. The main research component is the replacement of conventional Pb-Ag anodes with titan anodes. Ti anodes have demonstrated a good performance in reducing the potential for oxygen evolution in electrolysis cells. This potential reduction of about 300 to 400 mV can translate into energy savings of nearly 100 GWh per year, or about 10% of the energy consumption of electrolysis. However, in order to use new anodes, their long-term performance needs to be validated and peripheral technologies need to be developed; i.e. the control of Mn and Cl concentrations in the electrolysis cells. The second area of research involves increasing the efficiency of purification process of the zinc solution. More particularly, the cobalt cementation process is targeted. Currently about 6% of zinc production is reinjected into the process for the removal of cobalt.This research program therefore aims to develop new technologies for the management of Mn and Cl in the electrolyte, to validate the performance of titanium anodes in the zinc electrolysis process, and to increase the efficiency of the cobalt cementation process by a new method of preparing Zn powders. The results obtained as part of this research program will give a considerable technological advantage to our partners; CEZinc and Outotec.