Abstract
Generally, a heavy metal fixative is used for the treatment of incinerator fly ash to immobilize the heavy metal in it. On the other hand, flue gas treatment chemicals contain alkali, which is applied to neutralize the acidic chemicals in the fly ash. Excess flue gas treatment chemicals remain in the fly ash as unreacted alkalis. When chemicals are applied as a heavy metal fixative for fly ash, the remaining unreacted alkali have a negative effect on the reaction of the chemicals and the fly ash. In this paper, we realized the optimization of flue gas and fly ash treatment with a novel flue gas treatment chemical and an inorganic phosphate heavy metal fixative. In particular, decreasing the application rate of the inorganic phosphate heavy metal fixative was achieved by dramatically decreasing (by over 50 %) the alkalinity of the fly ash through the application of this novel flue gas treatment chemical. In addition, our optimized treatment improved the stability of the heavy metal immobilization in the treated fly ash in comparison with a conventional treatment using lime as the flue gas treatment chemical and organic chelate as the heavy metal fixative.
