Efficient vitrification of hazardous waste incineration fly ash and slag via the CaO-SiO2-Fe2O3 system.

Landfilling hazardous waste presents substantial environmental risks, necessitating the development of reliable and sustainable disposal technologies. This study explores a novel co-vitrification strategy for hazardous waste incineration fly ash (HWFA), slag (HWS), and iron-rich slag (IRS) by utilizing the CaO-SiO2-Fe2O3 ternary system. Theoretical analysis indicates that optimizing the ternary component ratios can achieve a minimum eutectic temperature of 1192 °C, significantly reducing the liquidus temperature compared to individual HWFA, HWS, and IRS raw materials. Systematic experimental validation confirms that this approach facilitates efficient vitrification at approximately 1300 °C, offering a substantial improvement over conventional thermal treatment process. Multi-factor interaction analysis reveals that melting temperature acts as the dominant factor, exhibiting a synergistic effect with holding time in enhancing the vitreous quality of the final product. Under the optimized conditions (HWFA:HWS:IRS ratio of 36.75:34.19:29.06; 1296 °C for 135 min), the resulting vitrified products demonstrate excellent chemical stability, with heavy metal leaching levels well below the regulatory thresholds stipulated in GB/T 41015-2021. This study proposes a scalable and energy-efficient strategy for the vitrification of hazardous waste, significantly advancing the field of hazardous waste management.