Study On The Influence Of Slag Composition On The Fluidity Of Primary Slag And Final Slag

With the rising prices of high-quality iron ore raw materials and the increasing demand from steel companies for lowering production costs,the effective use of cheap high-aluminum mines in blast furnaces has become the focus of steel companies.However,due to the high content of Al₂O₃ in the high-aluminum ore,the content of Al₂O₃ in the slag is bound to increase.The increase of Al₂O₃ content can easily lead to the formation of high melting point compounds in the slag,which makes the viscosity of the blast furnace slag increase,the fluidity deteriorates,and the slag Metallurgical performance is reduced.Therefore,through the research on the metallurgical properties of primary slag and final slag of A large blast furnace ironmaking enterprise,it provides basic data and theoretical support for the full utilization of high-aluminum ore in blast furnace smelting.In this paper,the metallurgical properties of the primary slag and the final slag were investigated by the five-component slag system?CaO-SiO₂-MgO-Al₂O₃-FeO?for the 7^#blast furnace primary slag and the 8^#blast furnace final slag of A large blast furnace ironmaking enterprise.The main conclusions were as follows:?1?When the Al₂O₃ mass fraction of 15.00%,the binary alkalinity R?CaO/SiO₂?=1.17,the viscosity and melting temperature of the final slag first decrease with the increase of the MgO mass fraction,when the MgO mass fraction is 7.50%The viscosity and melting temperature reached a minimum of 1650K?1377°C?.When the MgO mass fraction exceeded 7.50%and rose to 8.50%,the final slag viscosity was basically the same as 7.5%,and the melting temperature was 1648K?1375°C?.?2?It is analyzed by three sets of fixed binary alkalinity experiments of fixed MgO and Al₂O₃ content:when the MgO content in the final slag is at a relatively high level,the binary slag basicity increases and the final slag viscosity increases.The change is not large,but the melting temperature increases as the binary alkalinity increases.When the binary alkalinity is 1.05,the melting temperature of the final slag is the minimum,wherein the mass fraction of MgO is 8.50%,and the melting temperature of the mass fraction of Al₂O₃ is 17.50%,the lowest is 1640K?1367°C?.?3?The Al₂O₃ mass fraction is 20.00%,the binary alkalinity R?CaO/SiO₂?=1.17,and the high temperature viscosity of the final slag is good.When the MgO mass fraction is 9.00%,the final slag melting temperature is at least 1675K?1402°C?.Under the condition of ensuring stable furnace condition and abundant furnace temperature,the Al₂O₃ content in the final slag is allowed to rise to 20%.?4?The binary basicity R?CaO/SiO₂?=1.373,the mass fraction of Al₂O₃ is10.95%,the mass fraction of MgO is 7.38%,the initial slag viscosity and the melting temperature decrease with the increase of FeO mass fraction,and the FeO mass fraction The effect on the initial slag viscosity and the melting temperature is significant.The larger the FeO mass fraction,the smaller the viscosity and melting temperature of the primary slag.However,the FeO in the initial slag is too high,which is not conducive to blast furnace operation.Based on the experimental results of the final slag and the initial slag,in order to realize the application of high-aluminum ore in the production of blast furnace in A large blast furnace ironmaking enterprise,considering the effect of high alkalinity on the viscosity,the MgO content in the slag should be 7.5%,taking into account the characteristics of the melting temperature.The binary alkalinity R should be maintained between 1.05 and 1.15 to improve the metallurgical properties of the high Al₂O₃ slag.