Co-preparation of secondary aluminium ash-based ceramics from multi-solid wastes: Thermoanalytical kinetics and contaminant migration patterns

Abstract

Addressing the pressing dual challenges of pollution control and resource utilization of hazardous wastes, such as secondary aluminum ash (SAA) and municipal solid waste incineration fly ash (MSWIFA), this study investigates the synthesis of high-performance porous ceramics from SAA, MSWIFA and other industrial wastes. The method not only optimizes waste management but also effectively enhances the containment of pollutants. The influence of phase transitions, physical performances, thermoanalytical kinetics, pollutant migration, and the structural integrity of the resultant secondary aluminum ash-based porous ceramics (SAABPC) was systematically evaluated. The optimized formulation, with a 3:5 MSWIFA to SAA ratio and sintered at 1175 °C, achieved a compressive strength of 7.34 MPa, porosity of 60.33 %, and a bulk density of 0.87 g/cm³. Sintering gas analysis confirmed the potential of SAA to act as a self-foaming agent through the oxidation of AlN, releasing N<inf>2</inf>. The leaching tests demonstrated effective immobilization of Pb²⁺, Cr³⁺, Ni²⁺, Cu²⁺, and Zn²⁺, thereby significantly mitigating the environmental risks associated with heavy metals. The study underscores the robustness of the SAABPC silicate network in immobilizing heavy metal ions, and provides a sustainable solution for the synergistic safe disposal and materialisation of hazardous waste from multiple sources.