Preparation of high-strength lightweight porous ceramics of coal slime via foam-gelcasting method based on TIMA and thermodynamics of complex systems

This study presents an innovative approach for preparing full solid-waste coal slime-based lightweight porous ceramics with high mechanical strength through optimized foam-gelcasting technology. The Tescan Integrated Mineral Analyzer (TIMA) was employed to characterize the distribution of key components within the coal slime system. Thermodynamic simulations, utilizing Factsage software, coupled with TG-DSC and XRD analyses, were conducted to elucidate the compositional transformations and crystalline phase formation mechanisms of complex mineral systems during high-temperature sintering. Systematic investigations were conducted on the influence law of slurry pH on slurry stability, establishing the qualitative relationships between sintering temperature (1150–1300 °C) and the pore architecture and mechanical performance of ceramics. Optimal results achieved at pH = 10 and 1300 °C demonstrated exceptional porosity (69.5 %), low thermal conductivity (0.18 W/(m·K)), and remarkable compressive strength (12.84 MPa). 3D rendering and pore size analysis revealed favorable pore parameters, with an average pore size of 54.87 μm, surpassing conventional solid-waste derived ceramics. The developed material exhibits promising engineering applications in thermal insulation and lightweight construction, providing a high-value solution for coal slime utilization.