EXAFS study of copper in waste incineration fly ashes

Copper species such as CuCO₃, Cu(OH)₂, CuS and CuO were found in the bag house and EP (electrostatic precipitator) fly ashes of waste incineration processes by X-ray absorption near edge structural (XANES) spectroscopy. A small amount of Cu(I) and metallic Cu was found in the bag house fly ash. The averaged Cu-O bond distance in the fly ashes determined by EXAFS (extended X-ray absorption fine structural) was 1.96 Å with coordination numbers of 2.4-3.9. However, the Cu-(O)-Cu (2nd shell) bond distance of the fly ashes in the incineration process was decreased by 0.19-0.21 Å if compared to that of the CuO standard. The coordination numbers of the 2nd shell contribution to the bag house fly ash were not very significant.