Study of an Environmentally Friendly Method for the Dissolution of Precious Metal with Ionic Liquid and Iodoalkane

Gold as a precious metal resource has high recycling significance. However, the current extraction methods cannot achieve both efficiency and environmental friendliness. In this paper, we propose new gold leaching agent, which can leach under light condition by mixing iodoform (CHI3) with 1-butyl-3-methylimidazolium dicyanamide (BmimN(CN)2) ionic liquid. Under 25 °C 13 W incandescent lamp irradiation, yield of 100 wt%, average rate is 945 mg Au/(h·mol·CHI3) (18.9 times that cyanidation method). Through analysis results radical inhibition experiment, UV-Vis XPS, possible mechanism proposed: iodine generated oxidizes Au0 to Au+, then forms AuN(CN)2 coordinating N(CN)2−. Subsequently, liquid Au N(CN)2 form stable [Bmim]·[Au(N(CN)2)2] ion pair structure, further promoting dissolution reaction. The reach 81.9 wt% respectively, when applied ore waste electrical electronic equipment (WEEE); also catalyst adding Soxhlet extraction. show method not only efficient, mild, environmentally friendly, but strong adaptability wide application prospects.