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

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constituents. The amount of soluble Mn averaged 12.88 - + 6.29% in theIllinois Basin samples.The general trend of EP s lubility for t e Illinois Basin fly ashes was:S04-S > Ca, B > Cd > Sb, n, Mg > Zn, Na Mo > K, Ni, Cr, Cu > Be, Ba,Si , Al , and Fe. The gene a1 pattern of EP solu i 1 i ty for the suI3b-i -iNninousfly ash W1 was: S04-S > , As > Ca > Se > Mg, n > Mn > Na > KB and Ba;S04-S > B > K > Mo >> Se, Na > Ca > Zn, Mg > Be Cr > Mn, 5, and Ba wasthe order for the lignite fly ashes 2 and W3. However, these solubi 1 itytrends apply only to EP extracts; in dissimilar leaching environments,different extractability trends may be observed. In solubility or leachingexperiments in which extraction takes place in alkaline conditions (astypical with many fly ash leachates), different solubility regimes in theresulting alkaline solutions may take place, since the pH of the extract isoften the dominant factor controlling the solubility of many inorganicconstituents.The Cd level in the EP extract from I7 exceeded the recommended leveloutlined by the proposed 1J.S. EPA Resource Conservation and Recovery Act(RCRA) (Table 13). The concentrations listed are 100 times the EPA'sNational Interim Primary Drinking Water Standards (U.S. EPA, 1976).If the EP extract contains any constituent exceeding the maximum allowablelevel for that given contaminant in an EP aqueous extract, the parent wastemay be classified as a hazardous waste. The classification of a waste aspotentially hazardous may also be based on criteria other than the EP data(U.S. EPA, 1980). Fly ash was recently removed from the 1 ist of Subtitle Cin Section 3001 of RCRA. Therefore, all fly ashes are classified asTable 13. Contaminant concentrations (mg/L) in EP extracts qualifying for hazardous waste classification (U.S. EPA,1980).ConstituentArsenicBar i umCadmi umChromiumLe adivlercurySeleniumSi 1 verEndrinLi ndaneMethoxychlorToxaphene2,4-D2,4,5-TP Si lvexConcentration(mg/L)
nonhazardous wastes under present criteri ever, these gui deli nes arestill in a period of revision, and the status of fly ash as a nonhazardouswaste may be modified.If the status of power plant by-products were to be revised, one fly ash(17) would fall into the hazardous aste classif ication. There73.9% soluble Cd in this sample, releasing 1.38 mg Cd/L in solution; themaximum allowable extract level for Cd is 1.00 mg/L. On the basis of thesedata, the parent ashes of the other 11 EP extracts ould not be classifiedas hazardous wastes under the present criteria.Most aqueous systems of fly ash do not reach equilibrium in mostshort-term (24-hour) extraction tests (Elsee80) . Short -termextraction procedures w i l l leach out the morts, but otherelements such as Sb, As, Ba, and Se (James et al., 1977); and Ca, Cu, Fe,and Zn (Natusch et al., 1977) may be continuously leache into solution forperiods longer than 24 hours* Therefore, as a first apppredicting the water quality of ponded fly ash leachate, a long-termequilibration extraction procedure was designed to produce a solutionpotentially equilibrated with the solid waste. Fly ash ponds may reachmetastable equilibrium conditions if the rates of the chemical reactionscontrolling the solubility of the particular mineral phases involved areslow in comparison with the retention times of the water in the ponds.Five of the 12 fly ash samples were chosen for solubility studies by thislong-term equi 1 i bration (LTE) procedure to suggest the general chemicalcharacter of disposal ponds that may develop after these ashes have beenslurried. In the LTE procedure (in contrast to the EP method), the pH ofthe solutions was not adjusted, and a greater solid-to-1 iquid ratio (a 20%slurry wt/vol ) was used. These solutions were periodical ly sampled duringthe extraction period. Results for the two acidic fly ashes (12, I7), twoalkaline samples (13, I%), and one of the western samples (W2) arepresented in Tables 14, 15, 16, 17, and 18.It is difficult to make direct comparisons between the LTE data and thosefrom the EP because of the different pHs of the extractants, the length ofthe solubilization period, the method of agitation, and the ratios of solidto liquid used in each procedure. After 24 hours (the duration of the EPmethod), the two LTE solutions generated from the Illinois Basin fly ashes(I2 and 17) were acidic (pH 4.1), while the other two (I3 and 18) werealkaline (about pH 11). The western fly ash extract, 2, was highlyalkaline (pH 12.4).As suggested by the data in Tables 14-18, the solutions were probably notin chemical equilibrium with the solid phase after the first 24 hours ofsolubilization, because the concentrations of many aqueous speciescontinued to change for several weeks. Figures 24, 25. nd 26 graphicallydemonstrate the changes in concentrations of selected constituents forthree of the samples.
Page 1 and 2: lllinoiSTATSTAT
Page 3 and 4: V SURVEYatural Resources Building60
Page 5 and 6: TABLESSummary of the origin and gen
Page 7 and 8: The overall purpose of this investi
Page 9 and 10: steady state conditions in the disp
Page 11 and 12: total carbon determinations were ca
Page 13 and 14: y passing the extract through a col
Page 15 and 16: The GC-MS analyses were performed b
Page 17 and 18: with ultrapure water. The final HCl
Page 19 and 20: Be 3. Wlir~eraiogical composi'tion
Page 21 and 22: Table 6. Trace constituent concentr
Page 23 and 24: Table 7. Fly ash sample classificat
Page 25 and 26: Table 8. Carbon, sulfur, and benzen
Page 27 and 28: Wave number (cm-'Figure 8. Infrared
Page 29 and 30: Figure 12. HPLC chromatogram of the
Page 31 and 32: Figure 16. HPLC chromatogram of the
Page 34 and 35: Table 11. Organic components in the
Page 36 and 37: Figure 21. Gas chromatogram of the
Page 38 and 39: 4.Jrcrm c o mQU"* 'tn U.a-U U O NrO
Page 42 and 43: Table 14. Change in chemical compos
Page 44 and 45: Table 16. Change in chemical compos
Page 46 and 47: Change in chemical composition as a
Page 48 and 49: Figure 26. Changes in the concentra
Page 50 and 51: Table 19. Corytituents in the long-
Page 52 and 53: Table 21. The LC-50 values, amount
Page 54 and 55: Table 23. The range of concentratio
Page 56 and 57: Table 25. The range of concentratio
Page 58 and 59: Table 27. The mean initial lengths
Page 60 and 61: Table 32. The mean final lengths an
Page 62 and 63: Several of the extrbivalves ( ~ are
Page 64 and 65: The mean concentrations of various
Page 66 and 67: 1972). Cadmium is a dangerous cumul
Page 68 and 69: Bl umer, M., 1957, Removal of eleme
Page 70 and 71: Furr, A. K-, T. F, Parkinson, R. A.
Page 72 and 73: Murtha, M. J., and G. Burnet, 1979,
Page 74 and 75: Standard methods for examination of

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