Study on preparation of glass-ceramics from multiple solid waste and coupling mechanism of heavy metals

Solid wastes, such as municipal solid waste incineration fly ash (MSWI FA) and tailings, contain a large number of harmful components, which makes harmless and recycling treatment a challenge. Through high-temperature reconstruction, the solid waste containing heavy metals is prepared into glass-ceramics, which is an effective method to realize the harmless and resource utilization of solid waste. In this work, glass-ceramics were successfully prepared by using MSWI FA, waste glass, and lead-zinc tailings. The utilization rate of solid waste reached 91.74%. The coupling mechanism of heavy metals with Fe as the dominant factor and Zn, Cu, and Pb coexisting was explored. The results showed that the critical threshold of sintering temperature was 1000 °C. The properties of glass-ceramics can be greatly optimized when the temperature was higher than 1000 °C. Fe played a leading role in the migration and solidification process. Because of its higher displacement capacity, Fe was preferentially solidified in the form of hedenbergite and magnetite. Zn, Cu, and Pb solidified in the form of (Mg,Fe,Zn,Cu)Fe2O4 and Pb2+ respectively. The order of stabilization effect was Fe > Zn > Cu > Pb. All leaching concentrations of heavy metals were lower than the standard threshold, even if the heavy metals reached 20 wt%.