Copper Electrowinning from Supercritical Leachate of Printed Circuit Boards

The technological development propitiates the rapid replacement of electrical and electronic equipment, which makes it indispensable to develop recycling processes for the treatment of this equipment when discarded. Printed circuit boards (PCBs) are fundamental components of electrical and electronic equipment. PCBs are composed of ceramics, polymers, and metals. Copper is the metal that is present in the greatest percentage of mobile phone PCBs. The objective of this study was to recover copper in the form of metallic deposits from a copper solution extracted from comminuted PCBs through supercritical CO2 in the presence of cosolvents (H2O2 and H2SO4). A synthetic CuSO4 solution was employed to determine the ideal current density in the range of 250 to 540 A/m2. The electrowinning of the leachate solution from PCBs was performed at the determined current density. Using the current density of 250 A/m2, pH equal to 4, and temperature of 25 °C, a current efficiency of around 100% was achieved for the real solution. The deposit obtained showed a copper concentration of 95.97 wt%, recovering 40% of the copper contained in the solution in 300 min of electrowinning. It was observed that for a longer electrowinning time, the percentage of copper recovery could increase.