On the Design Robustness and Long-Term Performance of the Most Used Electrodes in the Copper Electrowinning Industry

Abstract

Performance in copper electrowinning 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 in this process. Internal electrode resistances affect parallel anode–cathode pair resistances. Therefore, it also alters balanced copper deposits, current efficiency, and cell voltage and power consumption of electrowinning cells. This paper summarizes the design characteristics of commercial stainless steel cathodes and cold-rolled lead–alloy anodes. It includes the evaluation of electrode performances under typical operating conditions using 3-D finite-element method analysis. The proposed evaluation of internal electrode resistance comprises nonlinear effects of electrical conduction, heat generation, and electrode position. The analysis of the design robustness of electrodes considers the most important elements, which help to maintain high current efficiency and electrical performance in the long term; that is to say, 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 are based on 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 between the robustness of electrode design and long term performance.