Thiosulfate leaching of gold from a mechanically activated CuPbZn concentrate

The hydrometallurgical processing of complex concentrates represents an ecologically attractive alternative with respect to classical pyrometallurgical technologies. The leaching of gold from a mechanochemically pretreated CuPbZn complex sulfide concentrate of Slovak origin using ammonium thiosulfate was studied. Physicochemical transformations in the concentrate due to mechanical activation have an influence on the rate of extraction and the recovery of gold. It was possible to achieve 99% gold recovery within 45 min for a sample mechanically activated at an energy input of 403 kWh t(-1). Only 54% of gold were recovered from the as-received concentrate in 120 min. Mechanical activation proved to be an appropriate pretreatment for this CuPbZn concentrate before extraction of gold into thiosulfate leaching solution. (C) 2002 Elsevier Science B.V. All rights reserved.