Co-fabrication of feldspar-cordierite ceramics from multi-solid wastes: Design, sintering behavior, and microstructural transformation

Abstract

Addressing the challenges of pollution control and resource utilization of hazardous wastes like secondary aluminum ash (SAA) and municipal solid waste incineration fly ash (MSWIFA), this study developed a method for synthesizing high-performance porous ceramics from mixed solid wastes. A systematic evaluation was conducted on the phase transformation, physical properties, high-temperature deformation, sintering kinetics, structural integrity, and pollutant control of the prepared porous ceramics. The results indicated that with SAA, MSWIFA, and serpentine contents of 29 %, 15 %, and 5 %, respectively, at a sintering temperature of 1180 ℃, the resulting porous ceramics achieved an optimal porosity of 55.28 %, a bulk density of 0.81 g/cm³, a compressive strength of 6.12 MPa, and a corrosion resistance of 91.01 %. Sintering kinetics revealed that the addition of 5 % serpentine resulted in the lowest activation energy for high-temperature sintering, at 153.80 kJ/mol. Removal rates for F^-, Cl^-, and NH<inf>3</inf>-N reached 94 %, with SAA formula ceramic achieving a fluoride (F^-) removal rate of 96.02 %, and S formula ceramic achieving removal rates of 99.92 % for Cl^- and 99.91 % for NH<inf>3</inf>-N. The leachate concentrations of the composite porous ceramics were below the relevant standard limits for construction concrete, ensuring environmental safety. This study highlights the significance of the silicate network structure in the melting and mechanical properties of the porous ceramics, providing a sustainable solution for the coordinated safe disposal and phase-oriented transformation of mixed solid wastes.