Thermodynamic and Kinetic Aspects of Sulfur Evaporation from Fe–C Alloy Droplets

Evaporative loss of sulfur from Fe-C-0.1 mass% S alloys was investigated using electromagnetic levitation. An inert atmosphere was maintained with a constant flow of purified argon. The influence of carbon concentration, up to carbon saturation, on the reaction kinetics was determined at 1873 K. The effect of carbon on the activity coefficient of sulfur in liquid iron was also evaluated. While the value for the first order interaction parameter was found to be in good agreement with data in the literature, the value for the second order parameter was higher than those measured using a conventional crucible approach involving gas dissolution into liquid iron. The results are consistent with the premise that sulfur loss is primarily due to the evolution of monatomic sulfur vapor.