Effect of melt structure property on Al2O3 activity in CaO-SiO2-Al2O3-MgO system for blast furnace slag with different Al2O3 content

With the shortage of high-quality iron ore resources, more and more attention has been paid to the blast furnace (BF) smelting of Al2O3-rich iron ore in recent years. Thus, investigation on the thermodynamics property of Al2O3-rich blast furnace slag was inevitable in order to produce high quality hot metal with low cost. In this paper, based on the determination of Al2O3 activity by reference slag method at 1873 K in previous study, the effect of the mechanism of slag structure property on Al2O3 activity in CaO-SiO2-MgO-Al2O3 system was discussed by Raman spectra analysis. It was found that the [AlO4] structure was polymerized and [SiO4] structure was depolymerized with the Al2O3 content increasing from 10 wt.% to 18 wt.%, which caused the Al2O3 activity increased.