Mechanism of Reaction between Refractory

This study investigates the conditions of formation of inclusions in steel during ladle refining in MgO-lined ladles, with a focus on the reaction mechanism between magnesium oxide (MgO) and aluminum deoxidised molten steel. The objective is to elucidate the internal oxidation-reduction processes that occur during the refining stage. Methodologically, the research combines experimental results with parallel thermodynamic studies to provide a comprehensive analysis. The findings indicate that there is an internal oxidation-reduction reaction between the MgO refractory and the molten steel. It was observed that a thin oxide layer forms at the interface due to the interaction of magnesium vapor and aluminum dissolved in the steel alongside CO generated from the MgO and carbon reaction. The oxide inclusions primarily consist of MgO and Al2O3, and some fine inclusions may form as secondary inclusions during cooling. Additionally, thermodynamic calculations show that during vacuum refining, decreasing pressure reduces the chemical compatibility of carbon-bonded magnesia for ladle lining. A detailed understanding of these reactions is essential for improving steel quality in metallurgical processes.