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

The application of an O-2-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 (O-18(2) and (CO2)-C-13) are used to study the competitive oxidation of O-2 and CO2, for Fe-C melts at 1873 K. Changes in gas mix composition during the decarburization of Fe-C melts with O-2-CO2 are monitored using an online mass spectrometer. The results show that when the O-2/CO2 ratio at the inlet is 4:1, the O-2 oxidation rate is approximately four times that of CO2. O-2 and CO2 decarburization abilities are found to be basically the same, even when the O-2 supply is more than sufficient. As for the ability to oxidize Fe in molten steel, when the ratio of O-2/CO2 at the inlet is 4:1, the O-2 oxidation rate is approximately seven times that of CO2, allowing us to conclude that CO2 is less able to compete with molten iron oxide.