Effect of collector, frother and depressant addition on the copper recovery and concentrate grade of the nchanga underground scavenger circuit of konkola copper mine - Zambia

Abstract

Nchanga copper ore is a complex mixture of sulphide and oxide minerals and processing involves sulphide flotation and the sulphide rougher/scavenger tails rich in oxide minerals (acid soluble copper) are sent to the Tailings Leach Plant for the recovery of the acidsoluble copper. Currently, the acid insoluble copper (sulphides) losses on the scavenger banks are very high, from about 0.3 % TCu to 0.77 % TCu. Mineralogical tests carried out on the scavenger feed samples showed that the valuable minerals were liberated. This indicated that the chemical environment might have an effect on the recovery of the sulphide minerals (acid insoluble copper) lost to the tailings. In this paper the effect of collector, frother and depressant addition on thecopper recovery and concentrate grade of the Nchanga Underground Scavenger circuit was studied. The investigation involved the flotation recovery of sulphide minerals from the scavenger feed uponaddition of the collector, frother and depressant. The reagent dose rates were varied as follows: collector (10, 30, 50 and 80 g/t), frother (10, 20, and 30 g/t), and depressant (40, 60, and 100 g/t). The results showed that the addition of TDSC 39/R9004A frother (maximum recovery 72.49 % TCu with a concentrate grade of 29.5 % TCu at a dose rate of 30 g/t) to the scavenger feed is more effective than the addition of SIPX collector (maximum recovery of 23.99 % TCu with a concentrate grade of 26 % TCu at a dose rate of 50 g/t). The depressant (Deptan 100) was more effective at lower dose rate of 40 g/t at which the level of insolubles reduced to 35 %.