An innovative method of recycling metals in printed circuit board (PCB) using solutions from PCB production

Waste printed circuit boards (WPCBs) have both a potentially high resource value and hazardous drawbacks. Meanwhile, large quantities of corrosive waste solutions are generated in PCB production. Existing methods for recycling metals in WPCBs produce high yields but unfortunately produce secondary pollution. In this study, to minimize these disadvantages, a win-win innovative recycling method for WPCBs was developed using waste solutions that are generated in PCB production. Both of the waste solutions - waste tin stripping solution (WTSS) and waste etching solution (WES) - had an enormous capacity to extract Pb, Sn, and Cu. It was suggested that 1 L of WTSS was potentially capable for dissolving solder from 3.6 to 7.2 kg of WPCBs under room temperature, while WES was capable for Cu leaching from 0.13-0.35 kg of WPCBs. Compared with conventional leaching solutions, it was demonstrated that approximately 1 kW h of electricity could be saved from the recycling process when WTSS and WES were used to recycle only 1 kg of WPCBs. The proposed approach can be expected to significantly reduce energy consumption for recycling metals from WPCBs, without additional waste solution generated, and to increase the potential value of WTSS and WES, as they can facilitate the recycling process.