PIXE ANALYSIS OF INDIVIDUAL PARTICLES IN COAL FLY ASH.

Consumption of coal is increasing as an alternative for petroleum. During the process, coal fly ash particles are produced and are disposed as an industrial waste. Coal ash contains toxic heavy metals, which leads to a concern about the possibility of leakage into environment. The spatial distribution and chemical form as well as elemental concentration of the toxic elements in the particles are important factors in assessing the leakage into the environment. In this study, we analyzed individual coal fly ash particles with 1 µm spatial resolution by using the simultaneous micro-PIXE/RBS/off-axis STIM system at Tohoku University. Eighty fly ash particles were analyzed. The particles are mainly composed of O, Si and Al and estimated as dioxide. Hydrogen and carbon are not observed in these particles. V, Zn, Sr, Cu, Ni, Mn, Cr and As are contained in the particles. The content of each element is quite different in each particle. These elements are distributed homogeneously. As an exception, Al, Ca, Fe, Zn, As and Zr are distributed on the surface of the particle which might be related to the combustion process. [ABSTRACT FROM AUTHOR]