CHEMICAL STUDIES OF STACK FLY-ASH FROM A COAL-FIRED POWER-PLANT

Concentrations of 42 minor and trace elements in four size fractions of stack fly ash from a large Western coal-fired power plant are reported. Mass median diameters of the four size fractions were 2.4, 3.7,6.0, and 18.5 µm. Based on the enrichments relative to coal as a function of fly-ash particle size, the elements are grouped into three classes: Group I, elements that show little or no enrichment in the small particle fraction (Al, Ca, Cs, Fe, Hf, K, Mg, Mn, Na, Rb, Sc, Ta, Th, Ti, and the rare earths: Ce, Dy, Eu, La, Nd, Sm, Tb, and Yb); Group II, elements whose enrichments increase with decreasing particle size (As, Cd, Ga, Mo, Pb, Sb, Se, W, and Zn); and Group III, elements whose behavior is intermediate to that of elements in Groups I and II (Ba, Be, Co, Cr, Cu, Ni, Sr, U, and V). The elements in Groups I and II are described in terms of their lithophilic and chalophilic geochemical behavior, respectively. The chemical behavior of individual elements in Group III is discussed. © 1979, American Chemical Society. All rights reserved.