Study on preparation of glass-ceramics from municipal solid waste incineration (MSWI) fly ash and chromium slag

In order to realize the harmless treatment of municipal solid waste incineration (MSWI) fly ash and chromium slag, the CaO–SiO2–Al2O3 glass-ceramics were successfully prepared by the one-step method using a mixture of lead-zinc tailings and coal gangue as a flux. The results showed that the mixture successfully reduced the melting temperature of MSWI fly ash with a maximum blending ratio of 70% at 1450 °C, and realized the co-sintering of chromium slag and the base glass of MSWI fly ash. In addition, according to the analysis results of XRD, SEM, and EDS, combined with heavy metal leaching data measured by the TCLP method, diopside ferrous crystals exerted a better solidification effect on Zn and Cd than did gehlenite crystals. Uvarovite crystals exhibited an effective solidification effect on Cr owing to the participation of Cr in its formation, and the toxicity assessment of heavy metals in all samples satisfied the demand of the EPA and the CN GB 5058.3. This work provides a consult for the low-cost, green and efficient treatment of chromium slag, MSWI fly ash, coal gangue, and lead-zinc tailings.