On the design robustness and long term performance of the most used electrodes in the copper electrowining industry

The performance of copper electrowining process is directly linked to the electrode´s hanger bar designs and plate assembly methods. The actual physical condition of the plate - hanger bar assembly and the internal resistance of electrodes are critical factors for electrowining practice. Electrode internal resistances affects parallel anode-cathode pair resistances, and correspondingly, balanced copper deposits, current efficiency, cell voltage and power consumption of electrowining cells. This paper summarizes the design characteristics of commercial stainless steel cathodes and cold-rolled lead-alloy anodes. It includes the evaluation of electrode´s performance under typical operating conditions using 3D finite element analysis. The proposed evaluation of electrode´s internal resistance comprises non-linear effects of electrical conduction, heat generation and electrodeposition. The analysis of the design robustness of electrodes considers the most important elements that help to maintain high current efficiency and electrical performance in the long term: mechanical strength, inherent straightness, resistance to dissolution of copper coating on hanger bars, galvanic corrosion of weld joints, and hanger bar resistance to annealing. Results use industrial measurements, test work by vendors and tankhouse operating data for benchmarking. The performance evaluation considers internal electrical resistance, contact shape design, contact loading, average contact resistance and lifetime current efficiency. The results highlight the relationship of electrode´s design robustness and long term performance.