MSWI Fly Ash Multiple Washing: Kinetics of Dissolution in Water, as Function of Time, Temperature and Dilution

Municipal solid waste incineration fly ash (FA) can represent a sustainable supply of supplementary material to the construction industries if it is pre-treated remove hazardous substances such as chloride, sulfate, and heavy metals. In this paper, phenomenology associated with water washing multi-cycle treatment FA investigated, focusing attention upon mineral dissolution process. The efficacy assessed by leaching tests, according European Standard, discussed in light occurring phases. water-to-solid (L/S) ratio crucial parameter, along number cycles, for removing halite sylvite, whereas quartz, calcite, anhydrite, an amorphous phase remain residue. sequential extraction method kinetics modelling provide further elements interpret processes, suggest that takes place through two-step mechanism. Altogether, multi-step L/S = 5 effective reducing contaminants under legal limits non-hazardous disposal, while non-reactive or reusable cannot be completely reached, owing sulfate some metals which still leached out from