Research On The Structure And Properties Of Molten Silicon Refining Slag

Slag refining has a long history and is the main refining method in the metallurgical industry.It can not only refine steel,but also refine other metals and alloys.For example,denitrification in high-purity steel refining processes and removal of impurities are now carried out on the basis of slag refining.Slag refining has a significant effect on the removal of B element in the metallurgical process of refining silicon.For the slag refining of silicon,it is essential to promote the promotion of metallurgy,the development of photovoltaic industry and the improvement of energy problems.From the former research of our group,the physicochemical properties of the slag and the structure have an important influence on the refining effect of the slag.Therefore,the study of slag structure and slag properties is of great significance for solving the removal of B,promoting the development of metallurgical methods and promoting the development of the light energy industry.CaO-SiO₂-B₂O₃ slag is the basic slag of slag refining,so to study its structure and properties are very important.Electrical conductivity is an important physicochemical property in slag,which not only provides a basis for model building but also reflects the information of slag structure.The properties of slag are determined by the slag structure.This paper studies the electrical conductivity from the structural level.In this paper,the four-electrode method was used to study the electrical conducitivty of slag and the structure of the slag was studied by raman and nuclear magnetic resonance.It is found that with the increase of B₂O₃ content,the degree of polymerization of the network structure increased in the slag,and the BO₃ triangular structural units and the BO₄ tetrahedral structural units appear.The BO₃ triangle structure unit is dominant.As the B₂O₃ content increases,the electrical conductivity of the slag increases,and the electrical conductivity of the slag increases with the temperature of the slag.At1600°C,the B₂O₃ content increases from 0%to 10%the conductivity of the slag increased from 0.118 to 0.224?^-1cm^-1.The slag electrical conductivity and temperature are subject to the Arrhenius formula.According to the slag structure-conductivity model,the slag conductivity decreases with the increase of the slag network polymerization degree,and increases with the increase of BO₃ triangular structure unit,with the increase of BO₄ tetrahedral structural unit.And decreasing,and wherein the order of influence on the conductivity of the slag is BO₃ triangular structural unit>BO₄ tetrahedral structural unit>NBO.The electrical conductivity of the slag was studied by the four-electrode method and the structure was studied by raman and nuclear magnetic resonance.From the study of the structure and elecrivcal conductivity of CaO-SiO₂-Al₂O₃-B₂O₃ slag,the network polymerization degree of slag increases with the increase of B₂O₃.The main structural units in the slag are BO₃ triangular structural unit,BO₄ tetrahedral structural unit,tetracoordinated AlO₄,pentacoordinated and hexacoordinated AlO₅ and AlO₆.A decrease in the content of Ca²⁺causes tetra-coordinated AlO₄ to convert between five-coordinate and six-coordinated AlO₅ and AlO₆.The presence of the five-coordinated AlO₅ structural unit has little effect on the electrical conductivity.The BO₃ triangular structural unit and the six-coordinated AlO₆ structural unit have the greatest influence on the electrical conductivity.At the same time,the degree of influence of the AlO₆structural unit on the electrical conductivity is four times that of the BO₄ tetrahedral structural unit.Through the structural analysis of different positions of the slag and structural analysis of samples obtained by rapid cooling under high temperature conditions by adding different electric fields to the slag,the influence of the electric field on the structure of the slag is found.The slag network structure will depolymerize.By increasing the strength of the electric field,the degree of depolymerization of the slag will be further increased,and the existing structural units will be transformed into simpler structural units.The result of slag refining is closely related to the physicochemical properties and structure of the slag.In this study,the relationship between structure and properties was constructed mainly by studying the electrical conductivity and the structure of slag.By studying the influence of the electric field on the slag structure studied he relationship of the electric field to the slag structure.Research from the structural level provides a theoretical basis for slag refining.