Abstract
To determine the thermodynamic properties of sulphur dissolved in liquid iron, the equilibrium in the reaction S+H2 (g)=H2S (g)
was investigated for the temperature range of 1550-1700°C and sulphur concentration up to about 2 pct., using an induction furnace.
Though these measurements have been done by many investigators, their results have scattered by such reasons as sulphur segregation in specimens and thermal diffusion of gas mixture.
After the improvement for these many problems to be solved, the following equilibrium relation was obtained.
log K (=pH2S/pH2·as) =-3200/T-0.863
The activity coefficient of sulphur in molten iron, that is fs, decreased with the increase in sulphur concentration, however its decreasing rate became smaller with increasing temperature, indicating that iron-sulphur solution had a tendency to approach on ideal state with increasing temperature.
The relationship among fs, sulphur concentration and temperature was given as follows, log fs=(-286/T+0.119)[%S].
