Characterization of Gas Flow and Corrosion Resistance in MgO-C Refractories

Abstract

Gas permeability is a key property of MgO-C refractories, as it is related to the porous structure and degradation mechanisms associated with the infiltration of slag. In this work, the gas permeability of two experimental MgO-C formulations, SZ1 and EF3, was characterized using nitrogen as the permeating gas and applying Darcy’s and Forchheimer’s models. The results showed deviations from linear behavior at high flow velocities, indicating the presence of inertial effects associated with the porous network. EF3 exhibited a higher viscous permeability (3.05 × 10^-13 m²) than SZ1 (2.78 × 10^-13 m²), despite its lower total porosity, suggesting that permeability depends on pore connectivity and distribution, in addition to pore volume. Additionally, EF3 showed a higher inertial coefficient (8.17 × 10^-10 m), revealing the influence of pore geometry on gas flow behavior. Corrosion tests at 1600 °C showed lower slag penetration in EF3 (5.02 mm²) compared with SZ1 (8.04 mm²), which was associated with its denser structure and lower open porosity. These results highlight the importance of characterizing the porous structure to understand gas transport and corrosion resistance in MgO-C refractories.