Flowability and Desulfurization of High Alumina Blast Furnace Slag

KTH viscosity model was applied to predict the viscosity of blast furnace slag with high content of alumina, and the viscosity measured by a viscosity meter. The relationship between flowability and chemical composition of the slag and temperature of molten iron was studied. Multiple linear regression analysis was conducted to demonstrate the effects of compositions of slag and molten iron on the desulfurization ability of slag. The results showed that a high proportion of Al2O3in the slag reduced the flowability of slag. The content of Al2O3should be controlled below 18.5%(ω), or at least below 19.5%(ω). A moderate content of MgO improved the flowability of slag. The mass ratio of(CaO+MgO) to(SiO2+Al2O3) in the slag should be controlled at above 0.92, while the mass ratio of CaO to SiO2should be lower than 1.2. The mass ratio of MgO to Al2O3should be higher than 0.48, while the MgO content was favorably less than 12.5%(ω) in the slag. The temperature of molten iron and mass ratio of CaO to SiO2in the slag were the main influential factors on the desulphurization ability of slag, by contrast, MgO content and other factors had little effect on it.