FIELD TRIAL TO ASSESS ASH LEACHABILITY AND GASEOUS EMISSIONS FROM BOILERS FIRING DEINKING RESIDUE

A field trial was performed to examine the chemistry and leachability of ash and gaseous emissions from boilers burning deinking residue tog ether with natural gas and bark. The results show that, for the boiler firing deinking residue with natural gas, increasing the combustion t emperature by increasing the gas flow rate had little effect on NOx em issions and ash chemistry. Fly ash consisted of mostly calcined clay, CaO and TiO2. Bottom ash was similar but had higher SiO2, Fe2O3, Na2O, K2O, and PbO contents than fly ash. Pb likely originated from clay us ed as a coating material. Hg was enriched in fly ash and particulates, but its concentration was too small to be of concern. The leachabilit y of both bottom ash and fly ash was low, particularly for boilers tha t burn deinking residue with bark due to the high CaO content.