| In bath smelting, the FeO activity of the slag plays an important role in slag-metal reactions. Knowledge of the relationship between slag composition and FeO activity is essential for effective control of the rate of reduction in the system and better control of hot metal chemistry. Because of its ability to measure oxygen potential rapidly and directly, oxygen sensors, Cr{dollar}sb{lcub}rm (s){rcub}{dollar} + Cr{dollar}sb2{dollar}O{dollar}sb{lcub}rm 3(s){rcub}{dollar} // ZrO{dollar}sb2{dollar}(MgO) // Fe{dollar}sb{lcub}(1){rcub}{dollar} + (FeO){dollar}sb{lcub}rm slag{rcub}{dollar}, are used as instruments to measure the FeO activity in slags which are in equilibrium with liquid iron. A series of measurements of the FeO activity by the EMF (electromotive force) technique, and MgO solubility by thermodynamic equilibrium in the typical bath smelting slags (CaO-SiO{dollar}sb2{dollar}-Al{dollar}sb2{dollar}O{dollar}sb3{dollar}-MgO{dollar}sb{lcub}rm sat{rcub}{dollar}-FeO) have been conducted. It has been found that the measured FeO activity coefficient is inversely proportional to FeO content in the slag and increases slightly with the increasing slag basicity which is defined as ((CaO+MgO)/SiO{dollar}sb2{dollar}) in mole fraction basis. The values of the FeO activity coefficient are in agreement with previously published data. The MgO solubility decreases with increasing FeO content in the slag and increasing slag basicity (CaO/SiO{dollar}sb2{dollar}). A special oxygen sensor was designed to directly measure the oxygen potential in the slag phase. In preliminary experiments, stable EMF signals from the oxygen sensors immersed in low FeO complex slags were obtained. |
