The use of mixed thiol collectors in the flotation of Nkomati sulphide ore

Includes bibliographical references.Mixtures of collectors are widely used in sulfide and platinum group mineral (PGM) flotation, and a range of performance benefits have been reported for many different systems. An increase in paymetal recovery and grade as well as increased rates of recovery at lower collector dosages has been observed when single collectors are replaced with multi-collector suites. These benefits have been attributed to increased carrying capacity of the froth phase, faster kinetics and increased recovery of middling or course particles. However, the mechanism of action of such collector suites is not clearly understood. Candidate selection of mixed collector suites is currently based on experience and contextual knowledge. The overall objective of this study was to experimentally identify a three component collector suite consisting of conventional collectors which could enhance the metallurgical performance of Nkomati nickel-copper sulfide ore. A three component collector suite consisting of sodium isobutyl xanthate (SIBX), sodium ethyl xanthate (SEX) and either sodium ethyl dithiophosphate (DTP) or sodium ethyl dithiocarbamate (DTC) was used. The scope of this work was confined to the use of xanthates, DTC’s and DTP’s since they are in common use in industry, are supplied over a relatively low price range and have shown potential performance enhancements when used as mixtures. The standard University of Cape Town (UCT) batch flotation procedure was used in this investigation and changes in electrochemical potential were monitored as collector was added to the flotation cell. It is hypothesised that the benefits of collector mixtures are only evident at low dosages, thus, dosages were carefully controlled. The study aimed to determine whether benefits of collector mixtures were dominant in the pulp or froth phase and suggest a possible mechanism of action