To elucidate the reoxidation mechanism of Al-killed ultra-low C steel by Fe_tO-containing slag, the kinetics of a reaction 2Al + 3(Fe_tO) = (Al₂O₃) + 3Fe between the steel and CaO–Al₂O₃–Fe_tO–MgO_sat. slag was investigated mostly at 1823 K. Al contents (total and soluble), and total O content in steel samples were measured during the reactions under various initial compositions of slag ((pct CaO)\(_0\)/(pct Al₂O₃)\(_0\), (Fe\(_t\)O)\(_0\)), and the reaction temperature. The experimental results were analyzed using the reaction rate model developed in the present study, which is based on probable rate controlling step and employing CALPHAD thermodynamics using FactSage thermochemical software and databases. When the (pct Fe\(_t\)O)\(_0\) was higher than 10, the rate model could explain the measured data with an assumption that the rate was solely controlled by mass transport of Al in the steel. However, mixed transport control theory should be used to interpret the reaction rate when the (pct Fe\(_t\)O)\(_0\) was lower than 10. Decreasing (pct Fe\(_t\)O) during the reoxidation reaction changes the reaction mechanism in terms of the mode of rate-controlling step. The mass transport coefficient of Al in the steel (k ^M_Al was \(5\times 10^{-4}\) m s\(^{-1}\) at 1823 K (1550 °C), which is in favorable agreement with those in the literature. The mass transport coefficients of Al\(_2\)O\(_3\) was formulated to depend on the viscosity of the slag. In the mixed transport control regime, the apparent mass transport coefficient gradually decreased due to the slow mass transport of Al\(_2\)O\(_3\) as a resistance to the overall mass transport. This was also additionally supported by evaluating the activation energy of the apparent mass transport coefficient, which turned out to increase as the reoxidation reaction proceeds. Therefore, it can be concluded that the reaction mechanism gradually changes during the reoxidation reaction. (pct CaO)\(_0\)/(pct Al\(_2\)O\(_3\))\(_0\) ratio affects the reoxidation rate only when (Fe\(_t\)O)\(_0\) was low.

为了阐明含Fe _t O 渣对 Al 镇静超低 C 钢的再氧化机制，钢与 CaO 之间的反应动力学 2 Al + 3(Fe _t O) = (Al ₂ O ₃ ) + 3Fe -Al ₂ O ₃ -Fe _t O-MgO_饱和。炉渣主要在 1823 K 下进行研究。 Al 含量（总和可溶），钢样品中的总 O 含量在不同初始炉渣成分（(pct CaO) \(_0\) /(pct Al ₂ O )下的反应过程中测量）₃ ) \(_0\) , (Fe \(_t\) O) \(_0\)) 和反应温度。使用本研究中开发的反应速率模型分析实验结果，该模型基于可能的速率控制步骤，并使用 FactSage 热化学软件和数据库采用 CALPHAD 热力学。当 (pct Fe \(_t\) O) \(_0\)高于 10 时，速率模型可以解释测量数据，假设速率仅受钢中铝的质量传输控制。但是，当 (pct Fe \(_t\) O) \(_0\)低于 10时，应使用混合输运控制理论来解释反应速率。 减少 (pct Fe \(_t\)O) 在再氧化反应期间，在速率控制步骤的模式方面改变了反应机制。钢中 Al 的传质系数 ( k ^M _Al为\(5\times 10^{-4}\) ms \(^{-1}\)在 1823 K (1550 °C)，这是有利的与文献一致. Al \(_2\) O \(_3\)的传质系数被公式化为取决于渣的粘度. 在混合输运控制制度下, 表观传质系数逐渐降低到 Al \(_2\) O \(_3\)的缓慢质量传输 作为对整体大众运输的阻力。这也得到了评估表观传质系数的活化能的额外支持，结果表明随着再氧化反应的进行而增加。因此，可以得出结论，在再氧化反应过程中，反应机理逐渐发生变化。(pct CaO) \(_0\) /(pct Al \(_2\) O \(_3\) ) \(_0\)比仅当 (Fe \(_t\) O) \(_0\ )很低。