The effect of mixed thiol collectors on the flotation of galena

Thiol collector mixtures are commonly used in the flotation of base metal sulphides and platinum-bearing ores. There are synergistic benefits claimed for these collector mixtures, with mixtures lowering total dosage requirements, improving coarse particle recovery and the rate of flotation.Some of these co-collectors are known to have frothing effects. Therefore, the aim of this study was to decouple froth and pulp effects and to consider only the bubble-particle attachments in the pulp. This was achieved through microflotation experiments, where various ratios of the ethyl and isobutyl chain lengths of xanthates, dithiocarbamates and dithiophosphates were used as collectors. The flotation recoveries and rate constants of galena were analysed as a function of particle size in order to determine whether collector mixtures produced any beneficial effects over those of using single collectors.Mixtures of ethyl xanthate with ethyl dithiocarbamate were shown to significantly increase rate and recovery of galena flotation above those of the single collectors. Mixtures of ethyl xanthate and ethyl dithiophosphate showed smaller improvements in recovery. However, isobutyl xanthate, as a single collector, was superior to the mixtures in all cases.

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► Collector mixtures significantly improved the rate and recovery of galena flotation.
► An ethyl xanthate, ethyl dithiocarbamate mixture improved recovery by 29.5%.
► An ethyl xanthate, ethyl dithiophosphate mixture improved recovery by 17%.