A new technology for recycling solder from waste printed circuit boards using ionic liquid.

Waste printed circuit boards (WPCBs) contain lots of valuable resources together with plenty of hazardous materials, which are considered both an attractive secondary resource and an environmental contaminant. In this study, a new technology for the recovery of solder from WPCBs using an ionic liquid of 1-ethyl-3-methylimizadolium tetrafluoroborate ([EMIM(+)][BF(4)(-)]) as a heating medium was investigated. Experimental results indicate that the separation of solder from WPCBs is complete when WPCBs are heated at 240 °C and [EMIM(+)][BF(4)(-)] is stirred at 150 rpm for 10 min. By observing the cross sections of WPCBs before and after treatment with the ionic liquid, it has been found that there is a initial delaminating phenomenon for WPCBs, which implies that [EMIM(+)][BF(4)(-)] can dissolve bromine epoxy resins of WPCBs to some extent. This clean and non-polluting technology offers a new way of recycling valuable materials from WPCBs and prevents the environmental pollution by WPCBs effectively.