Interaction between refractory for refining ladle and low-carbon low-silicon Al-killed molten steel.

This article investigates the interfacial reactions between low-carbon low-silicon aluminum-killed (Al-killed) molten steel and four types of refractory materials—MgO-C, MgO-Al₂O₃, Al₂O₃-SiC, and MgO-Al₂O₃-C—used in refining ladles at 1873 K. The study finds that each refractory forms distinct interface layers after 60 minutes of contact: a dense MgO layer for MgO-C, a (Fe, Mg)Al₂O₄ spinel layer for MgO-Al₂O₃, a Si-enriched MgAl₂O₄ layer for Al₂O₃-SiC, and a MgAl₂O₄ spinel layer for MgO-Al₂O₃-C. The average magnesium content at the interface decreases in the order MgO-C > MgO-Al₂O₃-C > Al₂O₃-SiC > MgO-Al₂O₃, with SiC in Al₂O₃-SiC refractory contributing additional silicon to the interface. Thermodynamic simulations corroborate experimental results, indicating that MgO-C refractory most significantly influences the magnesium content in molten steel, which has implications for optimizing refractory selection to improve steel refining efficiency and product quality.