Trace elements in combustion residues from a UK power station

Trace element analyses of combustion residues from Eggborough Power Station (UK) are re-examined and augmented with new data, which has enabled original conclusions [Fuel Process Technol 47 (1996) 79] to be extended in two areas and developed in a third. These are: (a) potential emissions through mass closure with the conclusion that of the elements analysed only As appears to have been lost from the system (mass closures for Se and Hg were not determined but these elements are also probably lost); (b) volatility of elements based on ratios of element concentrations in fly ash to furnace bottom ash and element concentrations in a fine ash fraction to a coarse fraction with the latter appearing to be the more sensitive indicator and (c) the percentage surface association based on trace element analyses of size-fractionated fly ash. From the latter it is concluded that As and Mo are predominantly surface associated with little contained within the glass or other phases, Cu, Zn and Pb have a surface association of about 50%, V, Cr and Ni a lower surface association of between 30 and 20% and Ba and Sr a minor association of about 10%. The same conclusion was also reached for As, Mo and Pb using LA-ICP-MS [Fuel 2004] with, in addition, a similar association suggested for U, Tl and Se.