A Novel, Solvent-Free Mechanochemistry Approach for Gold Extraction from Anode Slime

摘要

Gold extraction from anode slime often results in severe pollution as well as high consumption of reagents. Herein, a novel strategy, that in situ generates oxidative chlorine by a mechanochemistry approach, was developed for gold extraction from anode slime for the first time. By conducting dry ball milling of the mixed anode slime, KMnO_(4), and NH_(4)Cl, elemental gold in anode slime was efficiently converted into water-soluble AuCl_(3) and then separated from solids by simple water leaching. A high gold yield of 97.71% was achieved under optimal conditions of 0.15 g of NH_(4)Cl, water content of 9.09%, mass ratio of 20, rotation speed of 700 rpm, and reaction time of 60 min. Furthermore, this approach achieved a gold yield of 78.82%, while yields of other coexisting metals were nearly negligible. Compared with the hydrometallurgical process, this approach exhibited great advantages for its nearly solvent-free process, excellent selectivity for gold, and environmental friendliness.