Thermodynamic Interaction between Chromium and Sulfur in High Cr Containing Liquid Iron

Abstract

Thermodynamic interaction between chromium and sulfur in liquid iron was studied using the slag/metal equilibration technique to measure the effect of chromium on the equilibrium sulfur distribution between the slag and carbon saturated Fe–Cr–S alloys containing chromium up to 30 mass% in the temperature range from 1823 K to 1923 K. The sulfide capacity of the CaO–Al₂O₃ slag was separately determined using carbon saturated liquid Fe–S alloys under CO atmosphere as a function of temperature. The sulfur distribution decreases with chromium content and increases with melt temperature significantly. The specific effect of chromium on the activity coefficient of sulfur in liquid Fe–C_sat.–Cr–S alloys was determined by considering the effect of carbon on sulfur at carbon saturation. The interaction parameters determined in the present study were compared with the previous data determined by the gas-metal equilibration technique using a H₂S–H₂ gas mixture.