Based on the first-principles calculation of density functional theory(DFT),the characteristics of pyrochlore crystal,crystal plane structure and electronic structure,as well as its surface active sites and adsorption behavior were studied to optimize the flotation process and improve the mineral separation efficiency.The results of energy band and density of states analysis show that pyrochlore belongs to semiconductor,and the positively charged active sites on its surface are Nb atom and Ca atom.The reaction activity is strong,followed by O atom,and the lowest active atom is F atom.The F—Ca and O—Ca bonds are mainly ionic bonds,which are easy to break during crushing and grinding,thus exposing more Ca atom active sites on the surface of pyrochlore.The calculation results of surface bond breaking density and surface energy show that the common cleav-age planes of pyrochlore include(111)plane,(311)plane and(400)plane,among which(111)plane is most likely to ap-pear and stable.The surface differential charge density analysis shows that Nb and Ca atoms have strong metal properties,and collectors that can bind to Ca and Nb active sites should be given priority in flotation.The results of adsorption energy calcula-tion show that OHA-can chemically adsorb with Nb and Ca sites on the surface of pyrochlore.The five-membered ring chela-ting configuration formed by OHA-and Nb is the most stable,but the number of Ca sites is more,which also plays an important role in the collector adsorption process.
pyrochloredensity functional theory(111)surfaceactive site
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