Thermodynamics of the reaction of components of the Fe-S-O system in equilibrium with a CO-CO2-SO2 gas phase at 1300°C

The composition of a CO-CO2-SO2 gas phase in equilibrium with liquid iron containing dissolved sulfur and oxygen at 1300 degrees C is determined using a mass spectrometer, The sulfur and oxygen partial pressures, which are proportional to the activities of the dissolved nonmetals (sulfur and oxygen) in the melt, are calculated. On the basis of the theory of mixed solutions, expressions are obtained for the activities of oxygen and sulfur in the liquid iron, and the equilibrium of the reaction between the dissolved nonmetals and the gas phase is described. Comparison indicates that theoretical and experimental compositions of the equilibrium metallic phase are in good agreement.