Elaborately-designed high-service performance carbon refractory brick through refreshing the pore structure

In this study, the microporous structure of carbon refractory bricks was enhanced through the incorporation of innovative graphitic-silica microspheres with high chemical reactivity. These microspheres were synthesized via hydrothermal carbonization and catalytic graphitization, using silica sol and sucrose wastewater as raw materials. The elemental distribution and morphology of the products obtained through hydrothermal carbonization and catalytic graphitization were analyzed. Building on these findings, the effects of varying graphitic-silica microsphere contents on the phase composition, microstructure, physical properties, molten iron corrosion resistance, and high-temperature carbon dioxide corrosion resistance of the samples were investigated. Compared to samples without graphitic-silica microspheres, those containing the microspheres exhibited in-situ formation of SiC whiskers within the pores, creating a network structure that effectively subdivided the macropores and increased microporosity. Furthermore, these samples demonstrated significant improvements in density, compressive strength, thermal conductivity, and resistance to both molten iron corrosion and high-temperature carbon dioxide corrosion. As the microsphere content increased from 2 wt% to 8 wt%, the sample properties initially improved and then declined. At the optimal microsphere content of 4 wt%, the samples achieved a porosity of 7.5 %, a density of 1.78 g/cm³ , a compressive strength of 69.4 MPa, a thermal conductivity of 11.53 W/m·K, and excellent resistance to molten iron and carbon dioxide corrosion. This study offers an effective approach to improving the performance of carbon refractory bricks.