Harmless treatment of municipal solid waste incinerator fly ash through shaft furnace

Municipal solid waste incinerator fly ash (MSWI FA) is a type of waste that is harmful to the environment, and the melting treatment methods can treat MSWI FA, removing its potential negative impacts. However, special equipment is required for the FA melting process, which necessitates high costs. Metallurgical shaft furnaces (MSF) can melt MSWI FA efficiently. Therefore, the feasibility of using an MSF for FA treatment was studied herein. First, the fundamental physicochemical properties of the FA were analyzed. Then, the appearance and internal morphology of the FA were examined using a scanning electron microscope. Finally, melting experiments were designed according to the conditions of the MSF. The results show that slag changes into a glassy state under rapid cooling, which is beneficial to the solidification of harmful elements. These harmful elements, including Pb, Zn, and Cu, are thus reduced and volatilized into the flue gas under the MSF's reducing atmosphere. The harmful elements that enter the slag are solidified, causing its leaching toxicity to achieve the national standard requirements. Further, under the simulated MSF smelting conditions, the FA dioxin destroy removal efficiency realized more than 99.99% efficiency. Therefore, the harmless treatment of MAWI FA can be realized through MSF process.