Electrorefining behavior of a multicomponent copper alloy derived from waste printed circuit boards

Efficient recycling of waste electrical and electronic equipment (WEEE) is a major priority for the circular economy and sustainable resource management. This study proposes and investigates an integrated mechanical, pyrometallurgical, and electrochemical process for recovering copper from waste printed circuit boards (WPCBs), focusing on smelting metal concentrates into anodes (∼69 wt.% Cu) and subsequent electrorefining. Electrorefining of the anodes was carried out in an acidic sulfate medium (50 g⋅L⁻¹ Cu²⁺, 200 g⋅L⁻¹ H2SO4) at a constant temperature of 60 °C, at three applied cell voltages: 0.25 V, 0.30 V and 0.35 V. Experimental results indicated an optimal working window between 0.25 V and 0.30 V. In this range, cathodic deposits containing approximately ∼99% wt.elemental Cu and a maximum copper recovery yield of ∼ 89% were obtained. Increasing the cell voltage to 0.35 V caused a kinetic destabilization of the process. The XRD results are consistent with the proposed formation of Cu2O under conditions favoring local Cu⁺ accumulation and secondary precipitation; however, the present experimental data do not allow direct confirmation of the proposed intermediate Cu⁺ species. Also, X-ray fluorescence spectroscopy (ED-XRF) revealed a undesired incorporation of silver at the cathode (up to 0.97 wt.% at 0.35 V), may be attributed to secondary chemical dissolution induced by dissolved oxygen and by mechanical entrainment of fine particles from the anode slime (insoluble anodic residue) under the effect of agitation. The integrated method proved superior in selectivity, limiting the co-deposition of impurities such as Ni and Zn and offering an efficient solution for e-waste recycling.