A Novel Route for Copper Recovery from Waste Printed Circuit Boards via Mechanochemistry

This paper mainly introduces a novel route for copper recovery from waste printed circuit boards (WPCBs) via mechanochemistry. Copper in the crust is most commonly present as copper-iron-sulfide and copper-sulfide minerals (about 80%) and there exist many methods to extract copper from cooper ores in mineral engineering. It seems an alternative to transform the metallic components in obsolete materials to their corresponding compounds common in nature. By means of mechanochemistry, copper and sulfur were verified to form into copper sulfide in the model experiment, where, meanwhile, the optimal ball milling time was determined (20 minutes). In the real experiment, WPCB fragments and sulfur were mixed and ground for 20 minutes, no copper was detected by XRD analysis but copper sulfide was left. After leaching in sulfuric acid (3M) and hydrogen peroxide (30 wt%), the yield of copper reached nearly 95% and, also, resin was conserved for further utilization. This paper, for the first time, reports the green recovery route combining mechanical activation and sulfurization and may provide an alternative in other studies of metal recovery.