Trace Elemental Characterization of Fly ash by ICP-OES
M. Kröppl, I. Lahoz-Munoz - Trace Elemental Characterization of Fly ash by ICP-OES - XIII Italian-Hungarian Symposium on Spectrochemistry: Environmental Contamination and Food Safety, Las Palmas, Spain, 2009, pp. 112
The purpose of this study was the determination of heavy metal concentrations in ash samples of biomass incinerators. Therefore ash samples of different biomass incinerators in Upper Austria were compared. The ash samples were taken from the discharge of the filter of the gas cleaning system.
As the biofuel for the incinerators contains heavy metals also in the ashes heavy metals can be found. Heavy metals are not destroyed by the incineration process, but released through their effluents. The amount of the metals strongly depends on the composition of the input material (for example wood chips, bark, used wood, …). This could also be found in the measurements. Knowing the concentrations of heavy metals is therefore important for the decision of further treatment or utilisation of the ashes.
In an incineration process it is interesting to analyse the distribution of the emitted metals from the input material. Some of the metals can be found in the gas phase (for example mercury), others are localised on fly ash particles and again others are found in the bottom ash of biomass incinerators. In this investigation mainly fly ash was analysed for heavy metals. In the case of one incinerator the heavy metal contents were also measured in the bottom ash fraction.
For measurement the fly ash samples were at first dissolved in a microwave digestion unit using nitric acid and hydrochloric acid. Afterwards the metals Al, As, B, Ba, Cd, Co, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, Sb, Sr, Ti, Tl, V and Zn were analysed by ICP-OES. Especially Al, Fe, Mg, Mn and Zn could be found in higher concentrations in the fly ash samples.