Slag resistance mechanism of MgO–Mg2SiO4–SiC–C refractories containing porous multiphase aggregates. Issue 10 (15th May 2023) - Qi, Xin
Abstract: The slag resistance of MgO–SiC–C (MSC) refractories should be improved because of the mismatch in the thermal expansion coefficient between the aggregates and matrix, as well as the defects caused by the affinity between periclase and slag. In this study, MgO–Mg2 SiO4 –SiC–C (MMSC) refractories were prepared using porous multiphase MgO–Mg2 SiO4 (M-M2 S) aggregates to replace dense fused magnesia aggregates. Compared to MSC, the slag penetration index of MMSC decreased by 43.5%. The structure of the porous aggregates increased the surface roughness, and the multiphase composition of the aggregates decreased the mismatch of the thermal expansion coefficient with the matrix, thus reducing debonding between the aggregates and matrix. The aggregates and matrix in the MMSC formed an interlocking structure, which bound them more tightly to improve the slag resistance. The slag viscosity at different depths from the initial slag/refractory interface was calculated using the Ribond model. The M-M2 S aggregates increased Six Oy z− in the slag, which increased the slag polymerization and slag viscosity. The aggregates and matrix in the MMSC reacted with the slag to form high melting point phases, which reduced the channel of the slag. In addition, the penetration depth and velocity derived from the Washburn Equation were modified for the CaO–SiO2 –Al2 O3 –MgO–FeO slag and magnesia based refractory to accurately evaluate slag penetration.