Influence of Al2O3 Content on Liquid Phase Proportion and Fluidity of Primary Slag and Final Slag in Blast Furnace

The objective of this study is to understand the influence of Al2O3 on blast furnace operation by studying the properties of primary slag and final slag. The effects of Al2O3 on liquidus temperature, liquid phase proportion and fluidity in the CaO-MgO-SiO2-Al2O3-FeO quinary slag system have been discussed in this paper. The results show that the influence of Al2O3 on primary slag is decreasing the liquidus temperature and increasing the proportion of liquid phase, which lead to a high-pressure drop in the blast furnace, while the influence of Al2O3 on final slag is increasing the liquidus temperature and degrading the slag fluidity. It indicates that increasing MgO content will optimize the influence of Al2O3 and the proper MgO content ought to be greater than 9% in the primary slag. In addition, improving the value of CaO/SiO2 will also optimize the influence of Al2O3, but it is not obvious.