Dioxins control as co-processing water-washed municipal solid waste incineration fly ash in iron ore sintering process

Abstract

Co-processing water-washed municipal solid waste incineration fly ash (WM-FA) in iron ore sintering process is of great prospect. In this paper, the emission characteristics of dioxins during sintering process combined with WM-FA were studied, and the control method for dioxins was proposed. The results showed that adding WM-FA in the form of pellets with diameter 5–8 mm slightly influenced sinter quality. Increasing the diameter of WM-FA from 5–8 mm to 10–12 mm helped to reduce the concentration of PCDD/Fs from 1.0425 ng I-TEQ/N m3 to 0.7720 ng I-TEQ/N m3. However, compared with no WM-FA adding case, adding WM-FA pellets caused the increase of PCDD/Fs concentration in the sintering flue gas. A novel method for dioxin control was proposed through preparing WM-FA into 5–8 mm pellets and coated with CaO-containing additive with its function to adsorb and fix HCl and Cl2, which were the key components to synthesize dioxin. Due to the inhibiting effect of CaO to the chlorination reaction, the emission concentration of PCDD/Fs was decreased to 0.6240 ng I-TEQ/N m3, which was lower than that of no WM-FA adding case. The research findings lay a foundation for the resource utilization of WM-FA and the harmonious development of city and steel plant.