Evaluation and Control of Iron and Steelmaking Slags through Electrochemical FeO Sensor

One of the greatest obstacles to the application of physical chemistry principles to the elucidation of slag-metal reactions is a lack of knowledge of activities of the reacting species. To a large extent, oxygen potential of the slag phase governs iron and steelmaking practice. Without oxygen control by means of appropriate sensors, the behaviour of the other elements cannot be managed. In this paper, measurements of the FeO activity with various types of electrochemical FeO sensors will be described together with examples of their applications for improved strategies toward better practice for ladle metallurgy and sulphur and manganese distributions between slag and metal phases during steelmaking. Measurements of FeO activity have also been made in order to improve dephosphorization reactions. This type of work has led to significant reduction in volume of slag generated within the steelmaking vessel, which in turn, has important implications for refractory wear, metal yield, alloy recovery and improved productivity. Finally an on-line sensor is described which permits the oxygen potential to be determined for both the metal phase and the slag phase during steelmaking in the BOF.