Direct recovery of copper from printed circuit boards (PCBs) powder concentrate by a simultaneous electroleaching-electrodeposition process

摘要

In this paper, a novel process to produce copper from ground and concentrated printed circuit board (PCB) powder is presented. In this process, a powder sample containing approximately 48% copper and 40% other metals, as well as 12% non-metallic materials, was anodically dissolved in an acidic copper sulfate solution, while copper ions were simultaneously reduced on the cathode, producing pure electrolytic copper and a solid residue rich in tin, lead, non-metallic materials and with a small copper content The results indicated that agitation and temperature increase favored copper recovery. However, agitation was demonstrated to be the most important parameter for increasing the efficiency of copper recovery from PCBs. At 25 °C, an apparent copper recovery of 96% was achieved after a 15 h-electrolysis with an agitation speed of 415 rpm, while at 40 °C without agitation the apparent recovery was only 90%. Scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) analyses had indicated that the copper recovered from PCBs by this method did not contain detectable impurities, indicating that this process may be an interesting alternative route for copper recovery from PCBs, thereby permitting the recovery of tin and lead as a solder alloy, substantially decreasing the amount of residues and decreasing the environmental impact caused by such hazardous materials.