Recovery of copper from WPCBs using slurry electrolysis with ionic liquid [BSO3HPy]∙HSO4

Due to rapid innovation in electronic industries, the average lifetime of electronic devices has been shortening drastically, leading to a massive electronic waste production (E-waste). As an essential part of E-waste, waste printed circuit boards (WPCBs) attract considerable concerns to seek a green and cost-effective recycling approach. In this study, a green chemical, [BSO3HPy]HSO4, was used to replace H2SO4 in a slurry electrolytic system in order to recover valuable metal copper from WPCBs in one-step. The results indicate that as more H2SO4 is replaced by [BSO3HPy]HSO4, copper recovery rate and current efficiency first increased and then decreased, while copper powders purity showed a reverse tendency: increases first and then decreases. The substitution of H2SO4 by [BSO3HPy]HSO4 could effectively reduce the particle size of the obtained powders. When 10% H2SO4 was replaced by [BSO3HPy]HSO4, the recovery rate, current efficiency, purity and particle size of copper powders were 90.94%, 70.68%, 81.69% and 2.30 μm, respectively, thus reaching an optimal level. XRD results show that elemental Cu was the main mineral phase in the obtained powders. SEM and TEM results indicate that copper powders obtained in H2SO4-slurry-electrolysis system is dendritic and polycrystalline, whereas those obtained in an electrolytic solution with [BSO3HPy]HSO4 were in form of scattered monocrystalline particles.