Heavy metal adsorption onto flyash in waste incineration flue gases

The presence of heavy metals in incinerator flue gases is of environmental concern due to their associated toxic properties. The heavy metals are asso ciated with flyash. Several flyash samples from a range of municipal solid waste incinerators have been analysed by ICP and coupled SEM-EDX to determi ne their heavy metal concentration and also heavy metal composition in rela tion to physical morphology. Flyash is shown to contain a wide variety of h eavy metals and consists of complex potassium, sodium and calcium aluminosi licates which form spherical particles with an associated amorphous and cry stalline phase with an enriched metal content. An experimental reactor is d escribed which investigates the interaction of heavy metal species with fly ash under simulated furnace/flue gas conditions. The literature is reviewed in relation to the vaporization and condensation reactions of heavy metals under waste incinerator combustion and flue gas conditions.