Dithiophosphate (DTP) is classically used as a co-collector in sulfide mineral flotation to promote hydrophobicity on target particles. Notwithstanding the improved recoveries observed, DTP does not appear to behave as a conventional collector, since it has been shown that it does not adsorb onto certain sulfide mineral surfaces. Recent investigations have nevertheless indicated that when DTP does not adsorb onto the sulfide mineral surface, the presence of a non-ionic frother, such as an alcohol or polyglycol ether, activates a synergistic increase in pulp phase mineral recovery and bubble-particle attachment probability. In this paper, a regular solution approach is used to quantify the interactions between thiolate collectors and non-ionic frothers at the air-water interface, where no other methodology could demonstrate such interactions. Attractive interactions were observed between DTP and frothers, whereas no such interaction was observed between xanthate, a standard base metal sulfide collector. It is suggested that this is the first time that such interactions have been shown for the DTP-frother system and this may represent an important contribution to our understanding of the role of DTP reagents in the flotation process.
