Chemical and toxicological properties of coal fly ash - University of ...

Table 7. Fly ash sample classifications.SampleTypealkaline Modic siltacid C-Modic silt loamalkaline Modic siltalkaline Modic siltalkaline Modic siltalkaline Modic siltacid C, Zn-Fersic siltalkaline Modic siltalkaline Modic silta1 kal ine Ba-Modic si 1 talkaline B, Ba, Sr-Calsialicaalkaline 8, Ba, Sr-Calcica--aTexture was not determinedbituminous coals, one from a German bituminous coal and the other 17, samples were derived from subbituminous and lignite coals from the westernUS., India, and Australia.Fly ashes from eastern U.S. bituminous coals tended to fall on the leftside of the diagram in the Modic and Fersic fields (Fig. 5): this patternis reasonable, because the eastern U.S. coals generally have higherconcentrations of Fe than do western coals (Gluskoter et al., 1977). Flyashes from western U.S. lignite and subbituminous coals tended to plot onthe right side of the diagram in the Modic, Calsialic, and Calcic fields.Western U.S. coals are generally associated with higher levels of Ca, Mg,and Na than are eastern coals (Abernathy, 1969; Furr et al., 1977;Gluskoter et al., 1977). Near the Sialic- odic boundary are three f 1 yashes generated from lignite coals in India. Indian lignite coal ischaracteristically low in Ca (Chopra et al., 1979); therefore, these flyashes did not fit the general pattern fordhe U.S. ashes. Additional workwith high-iron fly ashes is needed to provide a clearer indication of thedistribution of Ferrics and Fercalcics; few such fly ashes are completelycharacterized in the literature. However, the magnetic fractions of someFersics and Modics can be classified as Ferrics, as shown in Figure 5.Solvent extractionFive fly ashes were extracted with benzene. An amount of elemental sulfurequivalent to about 10% of the total extractable material in each ash wasco-extracted with the organic matter and interfered with the quantification