Deoxidation Equilibrium of Liquid Iron with Barium

Abstract

Deoxidation of liquid iron with barium was studied in the temperature range from 1600 to 1700°C. Barium and oxygen dissolved in liquid iron were brought into equilibrium in presence of pure barium oxide in the lime crucible under the inert gas atmosphere of argon.
The equilibrium constant and standard free energy of the deoxidation reaction "BaO(s)=Ba(%)+O(%)" were obtained as follows:
logK=-9980/T-1.82 (±0.11)
ΔG°=191000+34.9T(J) (±4 kJ)
The temperature dependences of the interaction parameters were expressed by the following equations:
e^Ba_O=27.1-1.48×10⁵/T
e^O_Ba=233-1.27×10⁶/T
The standard free energy of solution of barium in liquid iron and the activity coefficient of barium in the infinite dilute liquid iron solution refered to pure barium (γ°_Ba) were calculated and discussed.