The flotation of pyrite using mixtures of dithiocarbamates and other thiol collectors.

Results are presented which show that when mixtures of dithiocarbamates are used to float pyrite, each component has a synergistic effect on the performance of the others. Best results were obtained when a 90:10 mole% ratio of di-n-propyl dithiocarbamate and cyclo-hexyl dithiocarbamate respectively was used. The mixtures yielded higher recoveries and grades and also resulted in a greater mass pull, greater recovery of coarse particles and enhanced selectivity. The increased recovery may be due either to the selective adsorption of different collectors on particular sites or the orientation of the alkyl chains causing better surface coverage. Increasing the dosage in the case of pure collectors and mixtures increased the recoveries and grades and effectively masked the synergistic effect. When mixtures of dithiocarbamates and other thiol collectors were used it was clear that the dithiocarbamates were the weakest collectors since the other thiol collectors all performed better than the pure dithiocarbamates or mixtures, irrespective of total dosage. Best results were achieved with a 90:10 mole% mixture of n-butyl xanthate and cyclo-hexyl dithiocarbamate. The method of collector addition (by premixing or simultaneous addition) made no difference but addition of the weaker collector before the stronger collector slightly enhanced performance. The addition of copper sulphate to various collectors marginally increased recoveries, but in the case of cyclo-hexyl dithiocarbamate resulted in a dramatic increase in recovery and grade.
Results are presented which show that when mixtures of dithiocarbamates are used to float pyrite, each component has a synergistic effect on the performance of the others. Best results were obtained when a 90:10 mole% ratio of di-n-propyl dithiocarbamate and cyclo-hexyl dithiocarbamate respectively was used. The mixtures yielded higher recoveries and grades and also resulted in a greater mass pull, greater recovery of coarse particles and enhanced selectivity. The increased recovery may be due either to the selective adsorption of different collectors on particular sites or the orientation of the alkyl chains causing better surface coverage. Increasing the dosage in the case of pure collectors and mixtures increased the recoveries and grades and effectively masked the synergistic effect. When mixtures of dithiocarbamates and other thiol collectors were used it was clear that the dithiocarbamates were the weakest collectors since the other thiol collectors all performed better than the pure dithiocarbamates or mixtures, irrespective of total dosage. Best results were achieved with a 90:10 mole% mixture of n-butyl xanthate and cyclo-hexyl dithiocarbamate. The method of collector addition (by premixing or simultaneous addition) made no difference but addition of the weaker collector before the stronger collector slightly enhanced performance. The addition of copper sulphate to various collectors marginally increased recoveries, but in the case of cyclo-hexyl dithiocarbamate resulted in a dramatic increase in recovery and grade.