The First-Principle Study On Vacancies In The Sphalerite And The Metal Atom Doping Of Sphalerite

In this thesis,the theory of density functional theory is used to calculate the effect of vacancies or metal atom doping on the microstructure and properties of sphalerite containing vacancies,doping metal atoms and exposed crystal surface to predict the flotation and leaching performance of impure sphalerite.The results show that the vacancies and the doping of iron,manganese,germanium and indium atoms can cause the lattice parameter and volume of the sphalerite cell change,and make the sphalerite be separated from the original stable structure.The free energy can be increased and the disintegration is easier.The zinc vacancies,sulfur vacancies and doping of germanium atoms make the sphalerite a direct bandgap p-type semiconductor.The doping of iron atom,manganese atom and indium atom will make the sphalerite into a direct bandgap n type semiconductor.Except germanium doping,the Fermi level shifts to the right because of the two kinds of vacancies and the other three kinds of doping,which is beneficial to improve the electron donor ability of sphalerite,and to improve the reaction process of sphalerite.Germanium atom doping causes the emergence of spikes near the Fermi level,and increases electronic activity,and also helps to improve the sphalerite reaction process.The crystal is easy to break away because of the high activity around the zinc vacancies and sulfur vacancies.The stability of the iron atom,the manganese atom and the indium atom in the unit cell is less than that of the zinc atom,and it is easy to get out of the crystal to further make the crystal to disintegrate.The stability of germanium atoms is similar to that of zinc atoms.The outermost atoms of the sphalerite(110)surface relax to the internal displacement,and the secondary atoms move outward,and the displacement of the outermost layer is more obvious.The displacement of the Zn atom is larger than that of the S atom and eventually forms a rich S and Zn-deficient surface,so sulfur atoms on the surface are easier to be adsorbed.At the same time,the(110)surface increases its conductivity and reactivity after relaxing,and the surface atoms are more active than the bulk atoms,and the outermost S atoms are more susceptible to oxidation reaction.