Characteristics And Regulation Mechanism Of Microcrystallization During Cooling And Solidification Of Copper Slag

Copper slag is a solid waste discharged and condensed by high temperature liquid during pyrometallurgical smelting of copper ore.According to statistics released by ICSG,copper production will reach 2030 million tons by 2020 and copper slag production will reach about 40 million tons per year.Copper slag has various components and complex structure,which is difficult to be effectively used.How to solve the problem of copper slag resource utilization with huge output,high emission temperature and great harm to environmental pollution has become a key constraint for the sustainable development of copper metallurgical industry.The purpose of this study is to regulate the slag composition in the process of smelting reduction and iron precipitation of copper slag tailings,and provide the basic conditions for slag ceramicization.Glass ceramic materials are prepared by melting method,so as to achieve the high-value and slag-free utilization of copper slag,reduce environmental pollution and rationally utilize resources.In this study,glass ceramic materials were prepared by melting method melting method waste residue of pyrometallurgical copper smelting industry as raw material.Firstly,the molding glass-ceramic materials were prepared by direct molten carbon thermal reduction to separate some valuable metal iron in copper slag and effectively control the composition ratio of slag,and the microstructure of glass-ceramic materials was studied.Then by adding Ca O,Si O₂,Al₂O₃,Mg O to adjust the slag structure and slag type,the effect of iron content on the preparation and crystallization of copper slag glass ceramics was studied.At the same time,the bending strength and compressive strength of the prepared glass ceramics were compared.The results show that using copper slag to reduce iron,controlling the content of iron oxide(about 12.5 wt%of the slag),Si O₂ and Ca O(the mass ratio of Ca O/Si O₂ is0.42)in the slag composition,direct injection molding and rapid condensation molding can obtain high strength molding glass ceramics.When the first-order heat treatment was heat treated by first-order heat treatment,900?was suitable as the crystallization temperature of the material,and the crystallization time was about 5 h.The bending strength and compressive strength could reach 42.5 MPa and 165.8 MPa,respectively.When the molding glass-ceramic material was heat treated by second-order heat treatment,695?was used as the nucleation temperature of molding glass-ceramic,and 835?was used as the crystallization temperature of molding glass-ceramic.After nucleation for 1 h and crystallization for 3 h,the bending strength and compressive strength could reach 43.1 MPa and 167 MPa,respectively.In the prepared glass ceramics,diopside is the main crystalline phase,followed by magnetite,and may also contain some wollastonite phase,with an average grain size of 0.0 4?m and 0.1?m.