Study On Electron Structure Differences And Surface Adsorption Properties Of Sulfide And Oxidized Minerals Of Fe,Pb,Zn

Quantum chemical calculations were used to study typical sulfide and oxide minerals of iron,lead and zinc,including pyrite(FeS2),hematite(Fe2O3),galena(PbS),cerussite(PbCO3),sphalerite(ZnS)and smithsonite(ZnCO3).Both crystal structure and electronic properties of those six minerals were studied.The slab models of pyrite(100),hematite(001),galena(100),cerussite(100),sphalerite(110)and smithsonite(101)were established and the adsorption of N,O,P and S atoms on these six mineral surface were studied.The main conclusions were as follows:(1)It could be concluded from the PDOS analysis results of these six minerals that the coordination bond of pyrite mainly consists of S 3p and Fe 3d orbitals;For hematite,the coordination bond of it mainly consists of O 2p and Fe 3d orbitals;For galena,mainly consists of S 3p and Pb 6p orbitals;For cerussite,mainly consists of O 2s and Pb 6p orbitals;For sphalerite,was mainly formed by S px and Zn dzz orbitals,S py and Zn dxx-yy orbitals;For smithsonite,was mainly formed by O 2p and Zn 3d orbitals.(2)The results of adsorption of N,O,P and S atoms on the Fe atom on the pyrite(100)surface indicated that electrons were all provided by the Fe atom to the target atom.Among the four adsorptions,the Fe 3dzy and 3dzx orbitals were mainly interacted with the corresponding p orbitals of the adsorbed atoms.Adsorption results showed that the collection effects of xanthate,aerofloat,and sulfur-nitrogen collectors with S atoms as their core atoms were stronger than those with O,P,and N as the representatives of fatty acids,citric acid and amines collectors.When the target atom was adsorbed on the hematite(001)surface,the electrons also transfered from the Fe atom to the target atom.Among those four adsorptions,the main interaction was Fe 3dzz orbital with p orbital of the target atom.Adsorption results showed that the collective effect of amine collectors on the hematite surface was better than xanthate,aerofloat and sulfur-nitrogen collectors.(3)The adsorption of N,O,P and S atoms on the Pb atom on the galena(100)surface indicated that electrons were all provided by the Pb atom to the target atom.Among these four adsorptions,the Pb 6pz was mainly interacted with the corresponding p orbitals of the adsorbed atoms.The adsorption results showed that the adsorption of O and N atoms on the galena surface was stronger than that of P and S atoms.When the four target atoms were adsorbed on the surface of cerussite(110),they were still adsorbed on the surface Pb atoms.For N-Pb adsorption and O-Pb adsorption,the electrons were transferred from the metal atom Pb to the non-metal target atom.It was the Pb 6py orbital played a major role in these two adsorptions.However,for P-Pb adsorption and S-Pb adsorption,the electrons transfered in the opposite direction and the major orbital was Pb 6px.The results showed that the adsorption capacities of N,O atoms on the surface of cerussite were stronger than P,S atoms.(4)As the three atoms of N,O and P were adsorbed on zinc atom of sphalerite(110)surface,the electrons were transferred from these three kinds of atoms to Zn atom,and when S atom was adsorbed on the surface of sphalerite(110),the electron transfered in contrast.It was the Zn 3py orbital played a major role in the adsorption of N and O atoms on the surface of sphalerite,while the Zn 3px and 3pz orbitals played a major role in the adsorption of P and S atoms.Adsorption results showed that the adsorption capacity of O atom on the surface of sphalerite was the best.When S atoms were adsorbed on the Zn atom on the smithsonite(101)surface,only then,did the electrons flow from the non-metal S atoms to the metal atoms Zn.The adsorption of other atoms was exactly the opposite.The adsorptions of O and P atoms on the smithsonite(101)surface was the most similar.The orbital that played a leading role was Zn 3pz.The adsorption capacity of N atoms on the smithsonite(101)surface was slightly weaker than the O and P atoms.While the adsorption of S atom on the smithsonite(101)surface belonged to a kind of metastable structure,which indicated that the S atom group was difficult to sulfurise the smithsonite(101)surface,the stability of the adsorption structure was poor,and sulfur-nitrogen collectors with S atoms as their core atoms were weeker than those with O,P,and N as the representatives of fatty acids,citric acid and amines collectors.