Competitive Oxidation of O2 and CO2 in Fe–C Melts Using Isotope Tracing Method

Abstract

The application of an O2–CO2 mixture gas in the steel industry makes an important contribution to energy savings and emissions reduction. To clarify the reaction mechanisms of this gas mixture, isotope gases (18O2 and 13CO2) are used to study the competitive oxidation of O2 and CO2, for Fe–C melts at 1873 K. Changes in gas mix composition during the decarburization of Fe–C melts with O2–CO2 are monitored using an online mass spectrometer. The results show that when the O2/CO2 ratio at the inlet is 4:1, the O2 oxidation rate is approximately four times that of CO2. O2 and CO2 decarburization abilities are found to be basically the same, even when the O2 supply is more than sufficient. As for the ability to oxidize Fe in molten steel, when the ratio of O2/CO2 at the inlet is 4:1, the O2 oxidation rate is approximately seven times that of CO2, allowing us to conclude that CO2 is less able to compete with molten iron oxide.