Studies On Collecting Capability Of Selective Collectors Of Chalcopyrite And Its Mechanism

In conventional flotation of Cu/S separation,it is general to collect Cu and depress S while keeping pulp in a high pH value with lime as S depressant.This method often brings along problems of high lime expenditure,activated difficulties of highly depressed S,and depression of noble metal such as Cu.Therefore,it is of great importance to prepare an efficient selectivity collector for chalcopyrite under neuter and alkalescent conditions.Pure specimens of chalcopyrite and pyrite were studied to investigate the effect of pulp pH(including adjusted pH with CaO),type (including thiourea,CSU31,and dithizone) and dosage of collectors on flotation behavior of the two minerals.Zeta potential,adsorption capacity and infrared spectrum were used to study the mechanism of the collectors on chalcopyrite and pyrite.Pure specimens flotation results show that the collecting abilities of thiourea,CSU31 and dithizone to chalcopyrite are stronger than pyrite at pH=2.7～12.The order of collecting ability for chalcopyrite is dithizone≥CSU31＞thiourea.Using CSU31 or dithizone as collector,chalcopyrite can be well collected at a low concentration of 4mg/L for CSU31 or 2.6×10^-6mol/L for dithizone.The recovery of chalcopyrite is most different from that of pyrite under the neutral and weak alkaline conditions.The comparation of adjusting pH by CaO and NaOH shows that CaO has little influence on the floatability of chalcopyrite,while it depresses pyrite strongly.The influence of Cu²⁺ ion on floatability of pyrite is presented.The recovery of pyrite in the case of adding 1mol/L Cu²⁺ is slightly higher than that without Cu²⁺ under acid condition,and it is not obvious under alkaline condition.The analyses of zeta potential show that zeta potential of chalcopyrite and pyrite surface can be affected by pH of pulp,type and dosage of collectors,and Cu²⁺ addition.Increase of pulp pH will cause decrease of zeta potential.Adding CSU31 or dithizone will cause zeta potential decrease of chalcopyrite and pyrite surface(zeta potential decrease of chalcopyrite is bigger).Increase of collector dosage will cause zeta potentials decrease of mineral surface(zeta potential decrease of chalcopyrite is faster).The analyses of adsorption capacity demonstrate that the adsorption capacity of thiourea,CSU31 and dithizone onto chalcopyrite surface is more than surface of pyrite.A linear relationship holds between adsorption capacity and the concentrations of collectors.Cu²⁺ can improve the adsorption capacity of collectors onto pyrite surface in acid conditions.The analyses of infrared spectrum prove that the adsorption of CSU31 and dithizone onto chalcopyrite surface is chemical absorption and physical adsorption onto pyrite surface.Adding Cu²⁺ doesn't affect interaction between collectors and pyrite.