Current status on leaching precious metals from waste printed circuit boards

Current research on leaching precious metals from waste printed circuit boards (PCBs) in the world is introduced. In the paper, hydrometallurgical processing techniques including cyanide leaching, thiourea leaching, thiosulfate leaching, and halide leaching of precious metals are addressed in detail. In order to develop an environmentally friendly technique for recovery of precious metals from Waste PCBs, a critical comparison of main leaching methods is analyzed based on three-scale analytic hierarchy process (AHP). The results suggest that thiourea leaching and iodide leaching make more possible to replace cyanide leaching. (C) 2012 Selection and/or peer-review under responsibility of Basel Convention Coordinating Centre for Asia and the Pacific and National Center of Solid Waste Management, Ministry of Environmental Protection of China.