Influence of ZrSiO4-SiC reinforcement on the decarburization and thermal shock behavior of MgO-C refractories

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The slag corrosion resistance and thermal shock and of MgO-C refractories are crucial in the steelmaking industry. The current study presents a novel approach to enhance these properties by incorporating reinforcing particles such as zircon and silicon carbide. MgO-C refractories containing various amounts of ZrSiO4 and SiC were prepared and subjected to slag corrosion and thermal shock tests. X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS) were used to characterize the microstructure and chemical composition of the samples. The findings demonstrated significant improvements in the overall performance of the refractories with the addition of zircon and silicon carbide. Thermal shock resistance increased from 11 cycles for MgO to 18 and 15 cycles due to the increased fracture toughness and altering crack propagation paths with the addition of ZrSiO4 and SiC particles. The formation of a CaZrO3 phase within pores significantly improved slag corrosion resistance. This led to a reduced slag penetration depth and a thinner decarburized layer compared to the unreinforced MgO-C refractory. SiC decomposition formed a protective silica layer, while zircon particles locked MgO grain boundaries, further enhancing corrosion resistance. The study proposes a corrosion mechanism based on the formation of microstructure containing dense and decarburized layers. These findings highlight the potential of reinforcing particles to improve the performance of MgO-C refractories in steelmaking applications.