Study On The Effect Of Homogenization In The Flotation Process Of Chalcopyrite And Galena

In the beneficiation of polymetallic sulfide ores,the separation of chalcopyrite and galena by flotation is a difficult problem.Many researchers have proposed that chalcopyrite and galena have similar natural floatability,which is the reason why it is difficult to separate them by flotation.Within a flotation circuit,the surface chemical compositions of sulfide minerals will be changed under the action of mechanical force,electrochemistry,unavoidable ions,and flotation reagents etc.At present,the effect of surface chemical compositions changes of chalcopyrite and galena in the flotation process on their flotation separation is still unclear.In this work,it was found that the surface chemical compositions of chalcopyrite and galena tend to be homogenized in the flotation process,which was called homogenization effect.Studying the homogenization effect in the flotation process of chalcopyrite and galena has important theoretical value and practical significance for understanding the flotation separation mechanism of chalcopyrite and galena.In this study,chalcopyrite and galena were the main research objects.Flotation test,To F-SIMS,PCA,MCR-ALS,ICP-OES,XPS,zeta potential,UV-Vis,and FTIR were applied to study the homogenization effect in the flotation process of Cu-Pb sulfide ore,the homogenization mechanism of chalcopyrite and galena in the flotation process,and the mechanism by which Fe Cl₃eliminated the influence of homogenization effect on flotation separation of chalcopyrite and galena in the ethyl xanthate system.To F-SIMS analysis results of Cu and Pb concentrates showed that the surface chemical compositions of chalcopyrite and galena tended to be homogenized in the flotation process.Compared with chalcopyrite and galena in Pb concentrate,the surfaces of chalcopyrite and galena in Cu concentrate were richer in copper sulfides,lead sulfides,and adsorption products of sodium diethyldithiocarbamate and ammonium dibutyl dithiophosphate,while the adsorption products of aluminum ion,magnesium ion,calcium ion and sodium silicate were less.During the mixed grinding process of chalcopyrite and galena,the dissolution of lead ions from galena was promoted by chalcopyrite,meanwhile,the dissolution of copper ions and iron ions from chalcopyrite was also promoted by galena.These dissolved ions were adsorbed on the mineral surface,making the fragment ions,such as Cu⁺,Fe⁺,Pb⁺,Pb OFe⁺,Pb OCu⁺,and Pb SCu⁺,can be detected on the surfaces of chalcopyrite and galena after mixed grinding,which indicated that the surface chemical compositions of chalcopyrite and galena tended to be homogenized during the mixed grinding process.Under the influence of copper ions and lead ions,the flotation behavior of galena and chalcopyrite was tended to be similar.When the collector was not present,the flotation of galena and chalcopyrite could be inhibited by copper ions and lead ions,respectively.When sodium diethyldithiocarbamate/ammonium dibutyl dithiophosphate was present,the inhibitory effect of copper ions on galena flotation and that of lead ions on chalcopyrite flotation were significantly weakened.When both sodium diethyldithiocarbamate/ammonium dibutyl dithiophosphate and depressant（Fe SO₄+Na₂SO₃）were present,the flotation of galena and chalcopyrite could be activated by copper ions and lead ions,respectively.Copper ions were mainly adsorbed on the sulfur-rich sites of galena surface,forming Cu（Ⅰ）–S species in the form of Pb_x–S_y–Cu–（OH）_z.The lattice substitution of lead ions for Fe and Cu in chalcopyrite lattice was not possible.Lead ions were adsorbed on the hydroxyl-rich sites and sulfur-rich sites of chalcopyrite surface,forming（OH）_z–Pb–O–Fe,（OH）_z–Pb–S_y–Cu_x,and（OH）_z–Pb–O–Cu species with decreasing content.Among the adsorbed lead species on chalcopyrite surface,the proportion of（OH）_z–Pb–S_y–Cu_x species did not exceed 29%.While after the copper ions treated galena interacted with sodium diethyldithiocarbamate and ammonium dibutyl dithiophosphate,copper diethyldithiocarbamate salt and copper dithiophosphate salt were formed on galena surface,respectively,and the formation of lead diethyldithiocarbamate salt and lead dithiophosphate salt was inhibited.After the lead ions treated chalcopyrite interacted with sodium diethyldithiocarbamate and ammonium dibutyl dithiophosphate,lead diethyldithiocarbamate salt and lead dithiophosphate salt were formed on chalcopyrite surface,respectively,and the formation of copper diethyldithiocarbamate salt and copper dithiophosphate salt was promoted.After the lead ions treated chalcopyrite interacted with sodium diethyldithiocarbamate and ammonium dibutyl dithiophosphate,lead diethyldithiocarbamate salt and lead dithiophosphate salt were formed on chalcopyrite surface,respectively,and the formation of copper diethyldithiocarbamate salt and copper dithiophosphate salt was promoted.The PCA analysis results of combined mass spectra dataset of chalcopyrite and galena showed that,when sodium diethyldithiocarbamate/ammonium dibutyl dithiophosphate was absent and present,the surface chemical compositions of chalcopyrite and galena were tended to be homogenized under the influence of lead ions and copper ions.The flotation test results of pure minerals showed that Fe Cl₃ could eliminate the influence of homogenization effect on the flotation separation of chalcopyrite and galena at p H 9.5 with ethyl xanthate as collector,thus realizing the selective separation of chalcopyrite and galena.Mechanism studies had found that the difference of surface compositions between galena and chalcopyrite were enlarged under the action of Fe Cl₃.Specifically,Fe Cl₃ had a weak influence on the surface chemical compositions of galena,but chalcopyrite was oxidized after being treated with Fe Cl₃,and most of the Cu,S,Pb,and ethyl xanthate adsorption products on its surface were removed,forming a surface riched in（oxy）hydroxide of iron and ferric（hydroxy）sulfate.The research results of this study improved and perfected the flotation separation theory of chalcopyrite and galena,and provided a surface chemical basis for regulating and controlling the flotation process of chalcopyrite and galena.