Solubility of Calcium and Oxygen in Molten Iron Equilibrated with Slag in CaO, Al2O3 or CaO-stabilized ZrO2 Crucible at 1873 K

This is the authors' abstract. We don't add key points for this paper.

The solubility of calcium and oxygen in molten iron equilibrated with CaO–Al2O3–ZrO2 molten slag in CaO, Al2O3 or 5.5 mass% CaO-stabilized ZrO2 crucible at 1873 K was measured by means of the slag-metal equilibrium partition method under Ar gas atmosphere. From the results by XRD and the phase diagram of CaO–Al2O3–ZrO2 system, the slag in a CaO crucible was in equilibrium with CaO·ZrO2 and CaO and the slag composition was 57.36 mass% CaO-34.86% Al2O3-7.78% ZrO2. The slag in a Al2O3 crucible was in equilibrium with CaO·2Al2O3 and ZrO2–CaO solid solution (Css) and the slag composition was 27.08 mass% CaO-53.42% Al2O3-19.50% ZrO2. The slag in a CaO-stabilized ZrO2 crucible was in equilibrium with ZrO2–CaO solid solution (Css) and CaO·ZrO2 and the slag composition was 30.38 mass% CaO- 51.56% Al2O3-18.06% ZrO2. The average concentrations of oxygen and calcium in molten iron in equilibrium with slag and compounds were 251 ppm and 3 ppm in a CaO crucible, 33 ppm and 4 ppm in an Al2O3 crucible and 21 ppm and 5 ppm in a CaO-stabilized ZrO2 crucible, respectively. The logarithm of equilibrium constant, logK, for the reaction of CaO(s) = Ca + O is –4.38 and the interaction parameter of eCaO is 31.8. The value is satisfied the thermodynamic phase stability.