CO absorption and desorption in liquid steel comprise highly significant reaction mechanisms for steelmaking operations such as decarburization, ladle degassing, and the production of rimming steel ingots. However, until present the difference in the mechanism of CO absorption versus desorption has not been clarified. In this study, the CO desorption and absorption experiments were performed by blowing Ar + CO (0% and 5% in volume fraction) gas mixture bubbles into liquid steel with low carbon content (12–19 ppm). The experimental data show that the rate of CO desorption is much lower than that of absorption. The carbon mass transfer in liquid steel is found to be the rate-limiting step with respect to CO absorption. For CO desorption, in addition to the carbon mass transfer, the interfacial reaction at the gas-liquid interface is found to pose an additional kinetic barrier. The present finding improves the understanding of the basic C–O reaction kinetics involved in many steelmaking processes and contributes to accurate modeling and precise control of industrial practices such as basic oxygen furnace (BOF) and argon oxygen decarburization (AOD).
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