Research on raw materials for Al₂O₃-SiC-C refractory castables used in blast furnace troughs is relatively well established. However, gaps remain in both laboratory and industrial trials concerning the performance of castables incorporating SiC-modified flake graphite and alternative carbon sources. This study investigated the sintering behavior, mechanical properties, and service performance of Al₂O₃-SiC-C castables utilizing varying contents of modified flake graphite, pitch, and carbon black as carbon sources. Samples were characterized using SEM, XRD, and EDS for phase composition and microstructural morphology analysis. Key findings revealed that the thermal expansion mismatch between the SiC coating and flake graphite in SiC-modified graphite generated a microcrack-toughening effect. This effect, combined with the synergistic reinforcement from both components, enhanced the mechanical properties. The SiC modification layer improved the wettability and oxidation resistance of the flake graphite. This modified graphite further contributed to enhanced erosion resistance through mechanisms of matrix pinning and crack deflection within the microstructure. However, the microcracks induced by thermal mismatch concurrently reduced erosion resistance, resulting in an overall limited net improvement in erosion resistance attributable to the modified graphite. Specimens containing 1 wt.% modified flake graphite exhibited the optimal overall performance. During industrial trials, this formulation unexpectedly demonstrated a water reduction mechanism requiring further investigation.

The effects of different clay addition amounts and zircon powder contents on the properties of steel-pouring brick were studied using bauxite particles, sintered mullite powder, and other materials as the main raw materials. The results showed that with the decrease of clay content, the bulk density of the samples changed slightly, but the cold modulus of rupture, compressive strength, hot modulus of rupture, and high-temperature volume stability were improved; the addition of zircon powder did not significantly change the basic properties, such as the bulk density of the brick, but significantly increased the high-temperature flexural strength. Therefore, under the addition of 5 wt.% clay and 1.5 wt.% zircon powder were used for the application. The results show that samples with this formula have good performance, and the surface of the cast steel is smooth. Therefore, the optimization of the mullite steel-pouring brick formula can adopt the strategy of the synergy effect of clay and zircon to improve its comprehensive performance.