Analysis of reaction and mechanism of incinerator fly ash roasting

Fly ash generated from a municipal waste incinerator is designated as a specially controlled substance in Japan, and it is obligatory to make it harmless before disposal. In a series of researches, we proposed a new treatment technology to make fly ash harmless, and performed thermodynamic investigations for removing major harmful heavy metals such as lead, cadmium, zinc, and chromium. This paper reports the strengthening mechanism of sintered pellets as treatment residue and the stabilization of minute residual heavy metals, centering on the effects of alkali salt and iron contained in the pellets as well as the effect of sintering in the pellet roasting process. Further, the development of advanced technologies is being required for recycling slag generated as byproducts from various smelting furnaces through effectively dealing with minute residual heavy metals contained in it, aiming at the steady expansion of its applications. This paper also reports the effectiveness of mixed treatment of incinerator fly ash and smelting slag.