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Sulfide capacities of iron-oxide containing slags in the "FeO"-Al 2 O 3 -SiO 2 , "FeO"-CaO-SiO 2 , "FeO"-MgO-SiO 2 , and "FeO"-MnO-SiO 2 systems were experimentally determined using gas-slag equilibration technique. The experiments were conducted in a temperature range of 1673 to 1923 K. The experimental data were employed to optimize the model parameters of a sulfide capacity model developed earlier in the present laboratory. Based on these parameters, along with those obtained in previous works, an equation was suggested to predict the sulfide capacities of the "FeO"-Al 2 O 3 -CaO-MgO-MnO-SiO 2 slags. The results of model predictions show reasonable agreement with the experimental values of the six-component slags determined as a part of this work.

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The viscosities of high alumina blast furnace slags were experimentally determined by the rotating cylinder method using the Brookfield digital viscometer model LVDV-II+ pro. Two different slag systems were considered for the current study, the CaO-SiO 2 -MgO-Al 2 O 3 quaternary and the CaO-SiO 2 -MgO-Al 2 O 3 -TiO 2 quinary system. Experiments were conducted in the temperature range of 1650 to 1873 K. The effects of temperature, basicity, TiO 2 , and silica activity of slags on viscosity were studied. The viscosity decreases with basicity for high alumina blast furnace slags with basicity in the range of 0.46 to 0.8. At high basicity (~0.8), slag viscosity decreases even with a small amount of TiO 2 (~2 pct) addition in the slag. With an increase in silica activity in the range of 0.1 to 0.4, the slag viscosity increases, the increases being steeper below the liquidus temperature.

In the present work, the viscosities in the CaO-Fe n O-SiO 2 ternary system have been measured by the rotating cylinder method involving a spindle and crucible made of iron. Nine slag compositions in the ternary system have been chosen with CaO varying between 5.5 and 45.5 pct mass, FeO between 10.0 and 70.0 pct mass, and one measurement each in the binary Fe n O-SiO 2 and CaO-SiO 2 melts. The measurements have been carried out in the temperature range of 1423 to 1753 K. The viscosity in this system is described as a function of temperature and composition using the model approach developed earlier at the present laboratory. The isoviscosity lines have been predicated at 1573, 1673, and 1723 K. Good agreement between the calculated results and the experimental data has been obtained.

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Most refining reactions in steelmaking involve oxidation of impurity element(s). The product(s) of oxidation either dissolve in the slag or escape as gaseous phase. The activities of oxygen in the metal (h O ), and that of ''FeO'' in slag (a FeO ), are major factors controlling these chemical reactions. The activities of oxygen and ''FeO'' are thermodynamically related, provided equilibrium distribution of oxygen between the slag and the metal is attained. This enables direct estimation of one parameter from the other. A thorough knowledge of the variation in activity of FeO, and factors affecting the same, is therefore of great importance in the process metallurgy of steelmaking. The present work experimentally measures the activity of FeO in steelmaking slags and attempts to develop a correlation for estimation of c(FeO) as a function of temperature and chemical composition of the slag.