Equilibria in Reactions of CO and CO₂ with Dissolved Oxygen and Carbon in Liquid Iron

Carbon and oxygen activities have been established in molten iron using CO-CO2 mixtures in the temperature range 1550 to 1750°C. Pressures of up to 70 atm were used to establish the required carbon activities up to carbon saturation at 1550°C in gas mixtures with CO2 contents between 0.76 and 8.21 pct. The lévitation technique was used to avoid any possible contamination and the effect of thermal diffusion in the gas mixture was measured and corrected for. The data obtained on carbon activities fall between those of previous workers at low carbon but measurements have been extended to the much higher carbon concentrations which had not been investigated previously. By using the same CO-CO2 mixture and varying the total pressure it was possible to measure the effect of carbon on oxygen concentration at fixed oxygen activity and it was found that carbon increases the activity coefficient of oxygen