Municipal waste incineration fly ashes: from a multi-element approach to market potential evaluation.

Aqua regia digestion was found to be sufficient to evaluated the recovery potential; except for the mass constituents Al, Si, Sn, Ti and the trace components Cr, Hf, Nb, U and W, for which HF-containing digestions delivered better recoveries. On different time scales, ashes were very homogenous and HCl- as well as H2SO4-supported leaching delivered, satisfying results within an hour (exceptions are, e.g., Bi and Sb). By applying characterisation factors of the life cycle assessment impact category "Resource depletion-minerals and metals" supplemented by the list of critical raw materials of the EU: Ag, Bi, Cd, Ga, In and Sb are most interesting elements to be recovered in future activities.