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A new survey of mercury in U.S. coals

Book ·
OSTI ID:43239
;  [1]
  1. Frontier Geosciences Inc., Seattle, WA (United States)
An novel analytical method for Hg in coal, based upon wet combustion, SnCl{sub 2} reduction, dual gold amalgamation, and cold vapor atomic fluorescence spectrometry (CVAFS) was recently developed. This method allows the economical determination of Hg in fossil fuels at the ng/g (parts per billion) level, with precision and accuracy of {+-} 5%. Over 150 fossil fuel samples, representing 123 distinct samples were analyzed as an initial survey of coal being burned at power plants in the United States. Samples were submitted by utilities, and represent fuel as received (after any pre-cleaning, etc.), rather than as mined. The samples represent coals of most types and from most regions of the country. Triplicate analyses at various levels of laboratory processing indicate that most of the variability within the same field sample, and homogenized lab samples is due to the analytical variability (approximately {+-} 5%). The mean Hg concentration appears lower (87.8 {+-} 79.1 ng/g, n = 123) than indicated by previous surveys, and is skewed toward lower concentrations (median 71 ng/g). These data suggest that U.S. coal Hg emissions may be 50% lower than has been estimated using earlier data. No correlation was observed between fuel Hg and S, ash, or BTU. Western sub-bituminous coals had a mean (46.1 {+-} 27.1 ng/g, n = 47) significantly lower than the grand mean, while a limited number of lignites gave the highest mean (221.3 {+-} 136.8 ng/g, n = 7).
OSTI ID:
43239
Report Number(s):
CONF-940930--
Country of Publication:
United States
Language:
English