Al2O3对高炉渣物化性能影响的理论分析

随着优质铁矿资源的消耗，钢铁企业可利用的铁矿原料品位逐渐降低。因此，高铝质铁矿资源越来越受到钢铁企业的关注，但高铝原料在高炉冶炼过程中会带来渣铁黏稠、炉温偏低、冶炼安全等一系列问题。本研究中采用FactSage热力学软件分析Al₂O₃质量分数对高炉渣平衡物相、熔化温度、相析出温度的影响以及高铝渣液相区变化和黏度变化，旨在为高炉冶炼高铝原料提供一定的基础支撑。研究发现：炉渣为低铝（5%～10%）含量时，随着Al₂O₃含量增加，炉渣熔化温度升高，析出相为黄长石相和纯物质相，高炉渣黏度变化不大，炉渣中SiO₂含量高，炉渣黏度过高，不适合高炉冶炼；炉渣为中铝（10%～15%）含量时，随着Al₂O₃含量增加，炉渣熔化温度升高，析出相为尖晶石相、黄长石相和纯物质相，高炉渣黏度增加幅度略有提高，Al₂O₃含量对高炉渣性质影响较小，增加炉渣二元碱度对炉渣黏度降低效果较明显；炉渣为高铝（15%～30%）含量时...

Theoretical analysis of the effect of Al2O3 on the physicochemical properties of blast furnace slag

With the consumption of high-quality iron ore resources, the grade of iron ore available to iron and steel enterprises gradually decreases. Therefore, high alumina iron ore resources have attracted more and more attention. However, high alumina materials in the smelting process in the blast furnace will bring a series of problems, such as viscous slag iron, low furnace temperature, and smelting safety issues. From the perspective of blast furnace slag, this paper analyzes the effects of Al₂O₃ mass fraction on equilibrium phase, melting temperature and phase precipitation temperature of blast furnace slag, as well as the changes of liquid phase zone and viscosity of high alumina slag by using FactSage thermodynamic software. The results show that 1) when the slag is of low alumina (5% to 10%), with the increase of Al₂O₃ content, the melting temperature of slag increases, and the precipitates are feldspar phase and pure material phase. The viscosity of blast furnace slag increases slowly. The content of SiO₂ in slag is large, and the viscosity of slag is too high, which is not suitable for blast furnace smelting. 2) When the slag is of medium alumina (10% to 15%), with the increase of Al₂O₃ content, the melting temperature of the slag increases, and the precipitates are spinel phase, feldspar phase and pure material phase. The viscosity of the blast furnace slag increases slightly when the content of alumina is low. The Al₂O₃ content has little effect on the properties of the blast furnace slag, and the increase of the binary basicity of the slag has an obvious effect on the decrease of the viscosity of the blast furnace slag. 3) When the slag contains high alumina (15% to 30%), with the increase of Al₂O₃ content, the melting temperature of the slag increases, the precipitated phases are spinel phase, feldspar phase and pure material phase. The viscosity of the blast furnace slag increases at a rate of 0.011 Pa·s/%. In order to ensure that the solid phase precipitation temperature and viscosity of the slag meet the normal blast furnace smelting requirements, it is suggested that MgO/Al₂O₃ should be in the range from 0.4 to 0.5, the binary alkalinity R₂ range should be between 1.1 and 1.3, and the mass fraction of TiO₂ can be appropriately increased to about 5% in neutral atmosphere.