Process development for recovery of copper and precious metals from waste printed circuit boards with emphasize on palladium and gold leaching and precipitation.

摘要: A novel hydrometallurgical process was proposed for selective recovery of Cu, Ag, Au and Pd from waste printed circuit boards (PCBs). More than 99% copper content dissolved by using two consecutive sulfuric acid leaching steps in the presence H2O2 as oxidizing agents. The solid residue 2nd step treated acidic thiourea ferric iron agent 85.76% 71.36% Ag dissolution achieved. precipitation leachate investigated different amounts sodium borohydride (SBH) a reducing agent. remained gold reside 3rd performed NaClO-HCl-H2O2 system effect parameters investigated. specially increased increasing NaClO concentration up to 10 V% any further has negligible effect. HCl 2.5 5 M. were endothermic raising temperature had positive on efficiency. kinetics quite fast after 30 min complete achieved, while need longer contact time. best conditions determined be M HCl, 1 H2O2, at 336 K 3 h with solid/liquid ratio 1/10. 100% what chloride precipitated 2 g/L SBH. Finally, flow sheet PCB proposed.