Study On Bonding Characteristics Of Selenium And Tellurium Compounds In Copper Anode Slime Based On First Principles

With the continuous development of society,people’s demand for rare and precious metals is increasing.Facing the problem of increasing shortage of resources,people have paid more and more attention to the recycling of secondary resources.Copper anode slime is rich in selenides,Tellurides and valuable metal elements.It is one of the important sources for extracting rare and precious metals.Its recovery and enrichment process has become more and more mature.In the treatment process of Selenide and Telluride,most of them focus on optimizing the process means.At present,there are few reports on the valence bond structure and microstructure of Selenium and Tellurium compounds in Copper anode slime.Aiming at the key problem of the change law of valence bond structure of Selenide and Telluride in the dissolution process,based on the first principle calculation of density functional theory,this paper studies the stability,electronic characteristics and bonding characteristics of crystal structure of Selenium and Telluride compounds,Through the simulation of doping,the change law of chemical bond between Selenide and Telluride in the roasting leaching process is explored,and the bonding behavior of doped S and O atoms in Selenium and Tellurium compounds is clarified,which provides a theoretical basis for the dissolution of Selenium and Tellurium compounds.The main research results are as follows:The calculated results show that the cohesive energies of Ag₂Se and Cu₂Se are negative,indicating the stability of their structures.The calculated band gaps are0.038e V and 0.86e V respectively.The differential charge density and electron localization function show that the bonding mode of Ag₂Se and Ag₂Te is the coexistence of metal bond,covalent bond and ionic bond,and the bonding mode of Au₂Te,cute and Cu₂Se is the coexistence of covalent bond and ionic bond;The density of states and charge density diagrams show that the covalent bond mechanism is caused by the hybridization between valence electron orbitals of atoms and the overlap of energy levels of electron clouds;The relationship between bond strength of five compounds was analyzed by calculating Mulliken layout number.By simulating the change of valence bond structure of selenium and tellurium compounds in the process of sulfation roasting with S and O atoms,it shows that the pair doping energy of S atoms significantly affects the electronic structure and bonding characteristics of Cu₂Se and Cu Te.At the same time,the change of bonding characteristics and electronic structure of selenium and tellurium compounds is that the P valence electron state of S atom affects the valence electron band in Telluride and Selenide,A new hybrid orbit has been formed.