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Mobilization and attenuation of trace elements in an artificially weathered fly ash. Final report

Technical Report ·
OSTI ID:5379519

A series of artifically weathered fly ash samples were analyzed to examine the leaching behavior of trace constituents. The weathered samples represented a sequence of ash residues ranging from strongly weathered materials in which the exterior reactive glass of the particles had been removed, to moderately and minimally weathered ash in which limited dissolution had occurred and secondary precipitation products were formed. Contents of trace elements were measured by instrumental neutron activation analysis (INAA). Analysis of the solid weathered residues rather than leachates provided information on the behavior of many trace elements whose concentrations in aqueous leachates are far too low to measure by most analytical methods. Release of trace elements from the highly leached ash was primarily determined by their distribution among phases within fly ash particles. Most trace elements were associated with the internal glassy matracies of the fly ash particles. The elements Rb, Cs, Pb, Ti, Hf, Ta, W and, by inference, Fr, Ge, Sn, Zr and Nb were not dissolved by acid leaching solutions and accumulated within highly weathered ash particles. Approximately 75% of the Mn, Sb, Th, Cr, Zn, Co, Br, Sc, the rare earth elements and by inference, Bi, Cd, and Y, originally contained in the ash remained in the weathered residues. Approximately 50% of the total Sr, Ba, V, Mo, U and, by inference, Li, in the fresh ash was mobilized and leached. The elements B, As, and Se were associated with the highly soluble ash fractions and were nearly completely leached from ash.

Research Organization:
Alberta Univ., Edmonton (Canada). Dept. of Soil Science
OSTI ID:
5379519
Report Number(s):
EPRI-EA-4747; ON: TI86920465
Country of Publication:
United States
Language:
English