Abstract: The efficient flotation separation of chalcopyrite from pyrite is crucial for utilizing copper sulfide resources. However,the unavoidable copper ions in the pulp activate pyrite,severely hindering separation efficiency.To reveal the under lying mechanism and guide collector selection,this study systematically investigated the impact of copper ion activation on the adsorption behavior and selectivity of different collectors on both minerals by integrating density functional theory (DFT) cal culations,molecular dynamics (MD) simulations,and flotation tests.The results indicate that Cu2+ preferentially adsorbs at the sulfur-top site on the pyrite (100) surface with an adsorption energy of -102.89 kJ/mol,significantly enhancing its surface re activity through charge transfer.Theoretical calculations suggest a negative correlation between a collector′s adsorption strength on chalcopyrite and its separation selectivity.Flotation tests verified that among the studied collectors,the order of collecting a bility for chalcopyrite from strong to weak is isobutyl xanthate,diammonium dibutyl dithiophosphate (DDA),diethyl dithiocar bamate (DDTC);Whereas the order of selectivity for Cu-S separation from strong to weak is DDA,DDTC,isobutyl xanthate. MD simulations further elucidated that copper ion activation non-selectively enhances collector adsorption on pyrite,substantial ly reducing the adsorption difference between pyrite and chalcopyrite,thereby deteriorating flotation selectivity.In conclusion, for pulp systems containing unavoidable copper ions,collectors with inherent high selectivity for chalcopyrite,such as DDA, should be prioritized to mitigate the activation effect and ensure separation performance.

Key words: chalcopyrite,pyrite,copper ion activation,flotation separation,selective collector,density functional theory , calculation