Preparation of microcrystalline glass by municipal solid waste incineration fly ash: heavy metals crystallization mechanism

Abstract

High-value utilization and pollution control of municipal solid waste incineration fly ash (MSWI FA) are global concerns. While microcrystalline glass has emerged as a promising solution, the immobilization and reduction of heavy metals remains a critical bottleneck hindering its application. This study proposed a synergistic preparation of high-performance and low-residue microcrystalline glass by MSWI FA, secondary aluminum ash (SAA), and fluorite tailings (FT). The prepared microcrystalline glass exhibited excellent performance, with Vickers hardness, and acid and alkali corrosion resistance reaching up to 8.71 GPa, 99.83 %, and 99.97 %, respectively. The deposited and semi-deposited heavy metals including Ba, Cu, and Cr were crystallized by replacing anorthite, diopside, and spinel to form a solid solution with immobilization efficiencies of 99.82 %, 98.51 %, and 99.12 %, respectively. Meanwhile, 97.47 % of Zn, 99.18 % of Pb, 100 % of Cd, 45.96 % of Cu, and 99.89 % of Cl could be volatilized and enriched in the secondary ash. Therefore, the proposal strategy of microcrystalline glass preparation by MSWI FA, SAA, and FT could be a potential route for high-value utilization.