Assessment of fly ashes by TCLP leaching test

Leaching of iron, manganese, zinc, vanadium and copper from fly ashes from lignite, black and brown coal in power stations with grate combustion was compared. The ashes were leached according to the regulation 338/1997 by the method described in a US EPA directive, with aqueous and reagent extracts at pH 2.9 and 4.9. The performed experiments proved that the method of preparation of aqueous extracts has no influence on the amount of a leached metal. The amounts of a metal leached by the toxicity characteristic leaching procedure (TCLP) in dependence on pH of the extraction reagent differ for the studied metals and fly ashes types