The knowledge of FexO activities in molten slags at lower temperatures is necessary for effective dephosphorization hot metal pretreatments. However, there have been still differences among the reference data FexO–CaO–SiO2 pseudo-ternary system 1573 K. In present study, were measured with an electrochemical technique order to reevaluate iso-activity curves FexO. Subsequently, CaO and SiO2 along...