Characterization and trace contaminant chemistry of coal combustion by-products

Miscellaneous · Fri Jan 01 00:00:00 EST 1993

OSTI ID:6750693

Ishak, C F

Seven different southeastern US coal fly ashes have been characterized as to their physical, chemical, morphological and mineralogical properties before being land-applied in order to understand their behavior in agricultural ecosystems. Three different samples of flue-gas desulfurization gypsum (FDG) from Florida and Illinois were also characterized. Fly ash has varying concentrations of trace contaminants. Of interest in this study are the oxyanions As, Se, Mo and B. Both batch adsorption and leaching studies using intact and packed columns were carried out on Appling soil. The sorption of inorganic anions decreased in the order phosphate > arsenate > molybdate > sulfate > borate. In the competitive adsorption study, arsenate was found to be competitive with phosphate, but molybdate and sulfate were not. In leaching studies, similar results were obtained with regards to the leachability of elements. Using alkaline ash at agronomic levels of 5 and 10 Mg/ha, B was the only element detectable in significant amounts, and has the potential to create toxicity to crops when land-applied. However, B is readily mobile and easily leached and thus may not be a problem. The presence of FDG in the ash seemed to enhance B movement in the soil. The levels of As present in leachates from treated columns were insignificant when compared to the control column. Comparison was also made between batch (static) and column (dynamic) adsorption. Adsorption was less in the column study. The small difference in the distribution coefficient value, K[sub d], between batch and dynamic adsorption, did not change the retardation factor (R) value significantly to alter the appearance of the BTC's.

• Research Organization: Georgia Univ., Athens, GA (United States)
• OSTI ID: 6750693
• Resource Relation: Other Information: Thesis (Ph.D.)
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
COAL
COMBUSTION PRODUCTS
FLY ASH
CHEMICAL COMPOSITION
CONTAMINATION
PHYSICAL PROPERTIES
WASTE PRODUCT UTILIZATION
AEROSOL WASTES
ASHES
CARBONACEOUS MATERIALS
ENERGY SOURCES
FOSSIL FUELS
FUELS
MATERIALS
RESIDUES
WASTES
010800* - Coal
Lignite
& Peat- Waste Management
010600 - Coal
Lignite
& Peat- Properties & Composition