In this work, carbon dioxide (CO₂) was investigated as a lifting gas in the Ruhrstahl–Heraeus (RH) decarburization process of ultra-low carbon steel. The main challenge was to determine whether the local carburization reaction leads to the carburization of molten steel with ultra-low carbon content. Thermodynamic analysis of the reaction of the Fe-C-O melt with CO₂ demonstrated that compared with traditional Ar injection, the decarburization rate can be improved during the early stage of the decarburization process. This occurs because oxygen that is present not only in molten steel but also produced by CO₂ dissociation can react with dissolved carbon to remove the carbon from molten steel. However, it is difficult to determine whether the decarburization rate can be influenced during the later stage by injecting CO₂. This is because the carburization reaction at the surface of CO₂ bubbles in the up-snorkel and the decarburization reaction at other reaction sites can occur simultaneously. Industrial test results demonstrated that compared with Ar injection, the decarburization rate was not significantly affected by CO₂ injection at the early stage, whereas it was reduced during the middle and later stages. Nevertheless, the average carbon content in molten steel after the RH treatment with CO₂ injection was only 2.6 ppm higher compared with that in Ar injection. Therefore, Ar can potentially be replaced by CO₂ in the RH decarburization process of ultra-low carbon steel based on economic and environmental considerations.

在这项工作中，研究了二氧化碳（CO ₂）作为超低碳钢Ruhrstahl-Heraeus（RH）脱碳过程中的提升气体。主要挑战是确定局部渗碳反应是否导致碳含量超低的钢水渗碳。Fe-CO熔体与CO ₂的反应的热力学分析表明，与传统的Ar注入相比，在脱碳过程的早期阶段可以提高脱碳速度。发生这种情况是因为氧气不仅存在于钢水中，而且还由CO ₂产生离解可以与溶解的碳发生反应，从而从钢水中去除碳。但是，难以确定在后期能否通过注入CO ₂来影响脱碳速度。这是因为在上通气管中的CO ₂气泡表面的渗碳反应和其他反应部位的脱碳反应可以同时发生。工业测试结果表明，与Ar注入相比，脱碳率在早期阶段不受CO ₂注入的显着影响，而在中后期则有所降低。尽管如此，用CO _2进行RH处理后，钢水中的平均碳含量与氩气注入相比，氩气注入仅高出2.6 ppm。因此，基于经济和环境方面的考虑，在超低碳钢的RH脱碳过程中，Ar可能被CO ₂代替。