Completely separating metals and nonmetals from waste printed circuit boards by slurry electrolysis

Completely separating and recovering metals and nonmetals from waste printed circuit boards (WPCBs) is key to e-waste recycling. Here we proposed a novel approach, slurry or suspension electrolysis, to separate metals and nonmetals from WPCBs. The factors that impact the separation rate during the slurry electrolysis were discussed in detail. The results indicate that CuSO4·5H2O, NaCl, H2SO4, WPCBs dosage, current and time could impact metals separating from WPCBs. Increasing NaCl and H2SO4 concentration and extending electrolysis time could effectively increase the metal and nonmetal separation rate, while increasing WPCBs dosage and current have negative impacts on the metal and nonmetal separation rate. Slurry electrolysis could directly and completely separate and recover metals from WPCBs with a separation rate up to 97.79% under the conditions of 3 g WPCBs dosage in 100 mL electrolyte, 30 g/L CuSO4·5H2O, 40 g/L NaCl, 150 g/L H2SO4, 0.5 A and 9 h. The separated micro-metal powders are mainly Cu, about 86.6%, without any nonmetal powders. Copper recovered is dendritic, with a copper recovery rate up to nearly 99%. Thus, slurry electrolysis shows a prospective future in e-waste reutilization, providing a way to enrich metals for all kinds of urban mines.