A SULPHIDE-CAPACITY PREDICTION MODEL OF BLAST-FURNACE SLAG

A sulphide-capacity prediction model of CaO-SiO2-MgO-Al2O3 slags was developed based on the ion and molecule coexistence theory (IMCT). The biggest advantage of the theoretical model of ion and molecule coexistence was the fact that it is easily popularized and applied within a multicomponent slag system. The sulphide capacity (Cs) of the slag for a blast furnace (BF) with high Al2O3 in the CaO-SiO2-MgO-Al2O3 system at 1773 K was measured by applying the slag-metal equilibrium method. The feasibility of the developed IMCT model was verified with the sulphide capacity measured during the experiment. The effects of R (w/% (CaO)/w/% (SiO2)), w/% (MgO)/w/% (Al2O3) and w/% (Al2O3) on the sulphide capacity were discussed. There is a good linear relationship between the experimental values and predicted values. Therefore, the theoretical model of ion and molecule coexistence can be used to calculate the sulphide capacity of a CaO-SiO2-MgO-Al2O3 quaternary slag system. When the amount of Al2O3 is 20 w/% and w/% MgO/w/% Al2O3 is 0.5, the sulphide capacity of the slag increases with an increase in R. When the amount of Al2O3 is 20 w/% and R = 1.30, the sulphide capacity of the slag increases with an increase in w/% MgO/w/% Al2O3. When R = 1.30 and w/% MgO/w/% Al2O3 = 0.4, the sulphide capacity of the slag decreases with an increase in w/% Al2O3.