Flotation of copper sulphide from copper smelter slag using multiple collectors and their mixtures

•Studied the response of different collectors and their mixture for the recovery of copper value from copper smelter slag.•Correlated the slag mineralogy with flotation performance of copper sulphide.•The role of single collectors and collector mixture were evaluated in terms of copper grade and recovery.•Examined the flotation results to investigate that whether there was synergistic effect arising from mixing collectors.•The information will help in the flotation of copper smelter slag for better copper grade and recovery.

Present work focuses on the differences in the performances obtained in the froth flotation of copper smelter slag with multiple collector viz. sodium iso-propyl xanthate (SIPX), sodium di-ethyl dithiophosphate (DTP) and alkyl hydroxamate at various dosages. Flotation tests were carried out using single collectors as well as various mixtures of the two collectors at different but constant total molar concentrations. Flotation performances were increased effectively by the combination of collectors. The findings show that a higher copper recovery (84.82%) was obtained when using a 40:160 g/t mixture of sodium iso-propyl xanthate (SIPX) with di-ethyl dithiophosphate compared to 78.11% with the best single collector. Similar recovery improvement (83.07%) was also observed by using a 160:40 g/t mixture of sodium iso-propyl xanthate (SIPX) with alkyl hydroxamate. The results indicate that in both cases DTP and alkyl hydroxamate played important role as co-collector with SIPX for the recovery of coarse interlocked copper bearing particles and has an important effect on the behaviour of the froth phase. However, comparatively higher mass recovery was obtained when hydroxamate was used as a co-collector, accompanied by poorer copper grades. In this context the co-collector DTP is advantageous for the improvement of copper grade and recovery from copper smelter slag.