Comparison of single and mixed reagent systems for flotation of copper sulphides from Nussir ore

Abstract

The present study investigates the application of thiol collectors and their mixtures on the flotation of copper-silver-gold minerals from a new copper mine located in northern Norway. The copper minerals (chalcopyrite, chalcocite, and bornite) are uniformly distributed in all size ranges in the ore sample under study. Silver, gold and PGM (platinum group minerals) are closely associated with these copper sulphides, although only in trace amounts. The identified gold and silver particles occurred as fine inclusions (~10–32 µm) in copper minerals. In order to maximise the recovery of these economically interesting minerals, improvements in the recovery of the base copper minerals are required. Chemicals used in flotation greatly influence metallurgical results. Consequently, the feasibility of selective sulphides flotation using sodium iso-butyl xanthate (SIBX), n-butoxycarbonyl-O-n-butyl thionocarbamate (BBT), disecondary butyl dithiophosphate (DBD) and their mixtures as collectors were studied since these were identified as promising subjects of investigation. This paper presents a thorough analysis and comparison of results from the application of these three collectors and their mixtures to pure minerals. An increase in copper recovery was observed in the presence of collector mixtures relative to single collectors. It was found that xanthate and thionocarbamate in the ratio of 1:3 exhibited a highest grade of 29% and 98% copper recovery. Additionally, a significant increase in gold and silver recoveries/grades was also noticed in the presence of collector mixtures. The recovery of PGM increased marginally at the expense of concentrate grade while using the collector mixtures. The current study also revealed that all these metallurgical results are strongly influenced by the ratio of the collectors in the mixture and particularly the sequence of collector addition.