Long-term stability of landfilled coal combustion by-products

McCarthy, Gregory J.; Butler, Raymond; Grier, Dean G.; Adamek, Steven D.; Parks, J.A.; Foster, H.

doi:10.1016/s0016-2361(96)00189-5

Cited by 10 publications

(7 citation statements)

References 3 publications

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“…In two previous studies of long-term alteration of coal combustion by-products, discussed at some length in McCarthy, et al (1997) and references therein, continued exposure of disposed CCBs to natural settings resulted in significant alteration of the original hydration products. After a period of two to five years at several monitored disposal sites with adequate access to moisture, the emplaced materials showed dramatic changes in physical properties.…”

Section: Coal Combustion By-product Diagenesismentioning

confidence: 99%

“…Another concern is the lack of knowledge of the long-term behavior of CCB materials when they are exposed to the environment. In some cases, the materials undergo a mineralogical alteration similar to natural diagenesis (McCarthy et al, 1997).…”

Section: Coal Combustion By-productsmentioning

confidence: 99%

“…Both of these limits have potential ramifications for CCB materials. First, the number of phases in CCBs is typically between six and twelve (Bender et al, 1993;McCarthy et al, 1997). Also, in CCBs with higher sodium content, the number of elements included in the phases can exceed nine.…”

Section: Limitations Of Gsasmentioning

confidence: 99%

“…Yet, with the shallow burial of landfilling, where pressure does not become significant, our studies indicate that the opposite effect can occur in CCBs. In two studies of test disposal cells, by-product diagenesis converted initially well-cemented solids into friable, soil-like materials (Weinberg, et al, 1993;Butler, et al, 1993;Butler, 1993;Weinberg and Hemmings, 1995;McCarthy, et al, 1995, McCarthy, et al, 1997.…”

Section: Coal Combustion By-product Diagenesismentioning

confidence: 99%

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Residues From Coal Conversion and Utilization: Advanced Mineralogical Characterization and Disposed Byproduct Diagenesis

McCarthy¹,

Grier²

2001

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Prior to the initiation of this study, understanding of the long-term behavior of environmentallyexposed Coal Combustion By-Products (CCBs) was lacking in (among others) two primary areas addressed in this work. First, no method had been successfully applied to achieve full quantitative analysis of the partitioning of chemical constituents into reactive or passive crystalline or noncrystalline compounds. Rather, only semi-quantitative methods were available, with large associated errors. Second, our understanding of the long-term behavior of various CCBs in contact with the natural environment was based on a relatively limited set of study materials. This study addressed these areas with two objectives, producing 1) a set of protocols for fully quantitative phase analysis using the Rietveld Quantitative X-ray Diffraction (RQXRD) method and 2) greater understanding of the hydrologic and geochemical nature of the long-term behavior of disposed and utilized CCBs. The RQXRD technique was initially tested using 1) mixtures of National Institute of Standards and Technology (NIST) crystalline standards, and 2) mixtures of synthetic reagents simulating various CCBs, to determine accuracy and precision of the method, and to determine the most favorable protocols to follow in order to efficiently quantify multi-phase mixtures. Four sets of borehole samples of disposed or utilized CCBs were retrieved and analyzed by RQXRD according to the protocols developed under the first objective. The first set of samples, from a Class F ash settling pond in Kentucky disposed for up to 20 years, showed little mineralogical alteration, as expected. The second set of samples, from an enbankment in Indiana containing a mixture of chain-grate (stoker) furnace ash and fluidized bed combustion (FBC) residues, showed formation of the mineral thaumasite, as observed in previously studied exposed FBC materials. Two high-calcium CCBs studied, including a dryprocess flue gas desulfurization (FGD) by-product disposed in the Midwest, and a mixture of Class C fly ash and wet process FGD by-product codisposed in North Dakota, appeared relatively unchanged mineralogically over the up to 5 and 17 years of emplacement, respectively. Each of these two materials contained mineralogies consistent with short-term hydration products of their respective starting (dry) materials. The hydration product ettringite persisted throughout the duration of emplacement at each site, and the diagenetic ash alteration product thaumasite did not form at either site. Explanations for the absence of thaumasite in these two sites include a lack of significant carbonate, sulfate, and alkalinity sources in the case of the North Dakota site, and a lack of sulfate, alkalinity, and sufficient moisture in the Midwest site. Potential for future thaumasite formation in these materials may exist if placed in contact with cold, wet materials containing the missing components listed above. In the presence of the sulfite scrubber mineral hannebachite, the ettringites formed had ...

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Section: Coal Combustion By-product Diagenesismentioning

confidence: 99%

Section: Coal Combustion By-productsmentioning

confidence: 99%

Section: Limitations Of Gsasmentioning

confidence: 99%

Section: Coal Combustion By-product Diagenesismentioning

confidence: 99%

See 2 more Smart Citations

Residues From Coal Conversion and Utilization: Advanced Mineralogical Characterization and Disposed Byproduct Diagenesis

McCarthy¹,

Grier²

2001

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show abstract

“…CCBs typically contain between six and twelve crystalline phases plus X-ray amorphous phase [1,3,4]. The Rietveld method has been extensively tested for accuracy and precision in multiphase analyses [5][6][7][8][9][10][11][12][13].…”

Section: Introductionmentioning

confidence: 99%

Residues From Coal Conversion and Utilization: Advanced Mineralogical Characterization and Disposed Byproduct Diagenesis

McCarthy¹,

Grier²

1998

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Application of thermal analysis in preservation and restoration of historic masonry materials

Brosnan

Sanders

Stroble

2013

J Therm Anal Calorim

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Long-term stability of landfilled coal combustion by-products

Cited by 10 publications

References 3 publications

Residues From Coal Conversion and Utilization: Advanced Mineralogical Characterization and Disposed Byproduct Diagenesis

Residues From Coal Conversion and Utilization: Advanced Mineralogical Characterization and Disposed Byproduct Diagenesis

Residues From Coal Conversion and Utilization: Advanced Mineralogical Characterization and Disposed Byproduct Diagenesis

Application of thermal analysis in preservation and restoration of historic masonry materials

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