Fly ash generated from incineration of municipal solid waste (MSW) when placed in landfills can under mild acid conditions can leach lead and cadmium. A process for stabilizing heavy metals in this fly ash is presented which involves calcining the fly ash in the presence of an oxygen containing gas stream at a temperature greater than about 400. degree. C. and less than about 600° C. for times from about 170 seconds up to about 5 hours fly ash which has been subjected to calcium scrubbing for acid gas removal. Such treated MSW fly ash will give leachates containing heavy metal concentrations less than the EPA regulatory limit.
展开▼