Waste electric porcelain-based refractory bricks with significantly enhanced mechanical properties: Preparation, characterization and mechanism

Using waste electric porcelain to produce refractory bricks is a viable technology. However, these bricks currently have lower mechanical strength compared to those made from mineral raw materials. This study optimized the proportions and sintering process to develop high-strength refractory bricks from waste electric porcelain. The impact of physical phase, crystallinity, sintering temperature, and fly ash content on the bricks properties was examined. The research found that low crystallinity in waste electric porcelain leads to disorganized growth of mullite nano whiskers at high temperatures, reducing mechanical strength due to insufficient support structures and stress concentration zones. The addition of fly ash promotes the formation of uniformly dispersed mullite columns through non-uniform nucleation, significantly improving mechanical properties by creating a collective tetrahedral structure. Bricks with 20 wt% fly ash sintered at 1440 °C achieved a flexural strength of 77.3 MPa, a compressive strength of 156 MPa, and an apparent porosity of 10.89 %. High-temperature simulations indicate that these bricks exhibit good compressive strength and deformation resistance, with no adhesion observed. These high strength refractory bricks have promising potential for use in various high-temperature applications, including kiln linings, high-temperature flue, high-temperature support components and other industrial processes where durability and thermal stability are critical.