Abstract:High-temperature incineration is the predominant method for managing municipal solidwaste, enabling effective heat and heavy metal recovery and facilitating efficient energy and resourcerecycling. Fly ash generated from municipal solid waste incineration contains various heavy metals,chloride salts, dioxins, and other harmful substances, seriously impacting the ecological environmentEnergy Environmental Protectionand human health. Vacuum melting treatment of fly ash effectively eliminates heavy metals andchloride salts, rapidly decomposes dioxins, and significantly reduces fly ash toxicity. This studyoptimized the temperature, vacuum level, and holding time for vacuum melting treatment, identifyingthe optimal conditions of 1 400 ℃, 100 Pa, and 3.0 hours. The total chlorine removal efficiency reached92.00%, and the soluble chlorine removal efficiency reached 96.85%. XRD phase analysis revealed thatNaCl and KCl disappeared, while crystalline phases of Ca, Si, and Al minerals appeared under optimalconditions. The removal rates of various heavy metals increased significantly, with removal efficienciesof 81.34%, 89.26%, 90.86%, and 88.00% for Cu, Zn, Pb, and Cd, respectively. SEM imaging of fly ashtreated under optimal conditions showed a uniform and smooth surface, indicating a transformation to amolten glass state. The DTPA method was used to assess the heavy metal toxicity. Results showed thatthe concentrations of Cu, Zn, Mn, and Ba in the treated samples were 48.51, 92.41, 51.93, and 48.52mg/kg, respectively. The toxicity of heavy metals (as measured by EDTA extraction) decreasedsignificantly compared to the original fly ash, although some ecological risks remain. After vacuummelting treatment, dioxin content and toxic equivalents were significantly reduced, with an overallemission reduction exceeding 96%. This study provides crucial insights for the vacuum melting disposalof fly ash, offering technical parameters and practical guidance for its safe disposal and resourceutilization. However, this study only examined the phase characteristics of fly ash but lacked acomprehensive analysis of pollutant migration and transformation mechanisms. Further research shouldfocus on the efficient resource utilization of the post-melting slag and investigate the mechanisms andkinetics of pollutant migration and transformation to develop more effective control strategies andtechnologies. Close-