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Title: Geochemistry and mineralogy of fly-ash from the Mae Moh lignite deposit, Thailand

Journal Article · · Energy Sources
; ;  [1];  [2]
  1. Univ. of Western Ontario, London, Ontario (Canada). Dept. of Geology
  2. Univ. of Chaing Mai (Thailand). Dept. of Geology

The concentration of 21 elements in fly ash from three boilers (75 MW, 150 MW, and 300 MW) at the EGAT power plant, Mae Moh, Thailand, were determined by INAA. The concentration of 10 major elements was determined by XRF. As, Co, Cr, Ni, Mo, and Sb generally increase in concentration going from bottom ash (BA) through the sequence of electrostatic precipitator ashes (ESPA) and reach maxima of As (352 ppm), Co (45 ppm), Cr (105 ppm), Mo (32 ppm), Ni (106 ppm), and Sb (15 ppm) in the ESPA. Ce, Cs, Fe, Hf, La, Sc, Ta, Tb, and Yb did not exhibit concentration trends or are variable except in the case of one boiler, which showed an increase going from BA to ESPA. Only Br decreased in composition going from BA to ESPA. Rb, Sm, U, and Th showed marked variation in trends. The major elements identified by EDS were Al, Si, S, K, Ca, Fe, and Ba, with minor amounts of Mg, Na, Ti, Mn, and Sr. Al, Si, K, and Ca occur together and are present in most of the fly-ash particles. Ba was found as a major component with Ca, Al, and Si. Fe and Ca are usually associated with sulfur. Some small spheres (< 5 {mu}m) are comprised almost entirely of Fe (probably as oxide). Symplectite textures are noted in high-Fe phases. All elements except Br are significantly enriched in the fly ash relative to the coal, which contains 35% ash. Particle chemistry is consistent with the major mineral phases identified by XRD, which include: quartz, magnetite, mullite, gehlenite, anorthite, hematite, anhydrite, and clinopyroxene.

Sponsoring Organization:
USDOE
OSTI ID:
28045
Report Number(s):
CONF-9305402-; ISSN 0090-8312; TRN: IM9516%%171
Journal Information:
Energy Sources, Vol. 17, Issue 1; Conference: Annual meeting of the Canadian Society of Coal and Organic Petrology, Calgary (Canada), 21-22 May 1993; Other Information: PBD: Jan-Feb 1995
Country of Publication:
United States
Language:
English