Thermodynamic activity of FeO in CaO–SiO₂–MnO–FeO–MgO molten slags

ABSTRACT

To understand the thermodynamic characteristics of the melting process for high manganese twinning-induced plasticity steel, the activity coefficient of FeO in molten slag of MnO–CaO–SiO₂–FeO–MgO slag system with up to 52 mass% MnO was measured at 1450°C by the experiments of the iron equilibrium between liquid silver and molten slag under the mixed gas atmosphere of CO, CO₂ and Ar. The effects of MnO, FeO and the basicity on the activity coefficient of FeO in molten slag were discussed. The relationships between the activity coefficients of FeO, the concentrations of FeO and MnO and the basicity ((mass% CaO + mass% MgO)/mass% SiO₂) were investigated by the regression analysis method. The results show that the activity coefficient of FeO was proportional to the reciprocal of FeO concentration, and increased slightly with the increasing MnO, but slowly decreased by increasing the basicity under the research conditions.

KEYWORDS:

• Thermodynamics
• activity coefficient
• iron oxide
• activity
• slag
• TWIP steel

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

The author expresses his gratitude to the funding support by National Natural Science Foundation of China [grant number 51174137] and [grant number 51874198].