Improving flotation recovery of copper sulphides by nitrogen gas and sulphidisation conditioning

This paper describes investigations to increase the flotation recovery of c opper from ores containing both primary and secondary copper minerals. An i ncrease in the flotation recovery of copper is obtained by conducting contr olled potential sulphidisation conditioning in the absence of dissolved oxy gen. Sulphidising reagents have been widely employed for the flotation of s econdary copper minerals and in the case of molybdenum production the flota tion depression of copper sulphides. However, by using nitrogen gas to excl ude oxygen and by careful control of the sulphidisation process it has been possible to increase the flotation recovery of chalcocite, chalcopyrite an d bornite. The additional recovery is believed to be from particles with ox idised or tarnished surfaces where surface oxidation has been reversed. The use of nitrogen to exclude oxygen increases the efficacy of new sulphide s urface formation and improves process efficiencies by maximising the availa bility of sulphide ions for surface sulphidisation to occur at the lowest s ulphide consumption levels. (C) 2000 Elsevier Science Ltd. All rights reser ved.