Distribution of inorganics in low-rank coals. [Includes possible associations for many elements]

Technical Report · Fri Jun 01 04:00:00 EDT 1984

OSTI ID:7182282

Benson, S A

The inorganic components of low-rank coals have been examined to determine the differences in the modes of occurrence of major elements in high- and low-fouling coals and to examine the associations of minor and trace elements with minerals and organic fractions of the coals. The interrelationships of the inorganic elements and organic components have been determined by a combination of chemical fractionation, mineralogy by LTA/XRD and SEM, carboxylic acid group analysis, and statistical correlations. The modes of occurrence of inorganic components can be related to the mineral transformations that occur upon ashing the coals at 750/sup 0/ and 1000/sup 0/C. The ashes produced from the high-sodium coals exhibit a quite different behavior compared to the low-sodium coals. The ashes were examined by x-ray diffraction. A low melting phase was identified in both high-sodium coals but not in the low-sodium coals (solid solution aluminosilicate (melilites) with a general formula (Na,Ca)/sub 2/(Mg,Al)(Al,Si)/sub 2/O/sub 7/). These phases form in silica deficient systems. Melilites have been identified in the matrix materials of ash deposits formed during the combustion of high-fouling coals. The high-fouling coals are characteristic of higher concentrations of organically bound sodium and calcium and lower concentrations of silicon and aluminum. This pattern of concentrations appears to be the key to the formation of the melilites. By comparison, the low-fouling coals are relatively very high in silicon and slightly higher in aluminum along with being in sodium and calcium. Ashes of this type are more likely to form higher melting species, presumably less prone to form boiler tube deposits. 19 references, 3 tables.

• Research Organization: North Dakota Univ., Grand Forks (USA). Energy Research Center
• DOE Contract Number: FC21-83FE60181
• OSTI ID: 7182282
• Report Number(s): DOE/FE/60181-91; CONF-8406121-2; ON: DE84012923
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010600* -- Coal
Lignite
& Peat-- Properties & Composition
ASHES
BOILERS
BROWN COAL
CARBONACEOUS MATERIALS
CHEMICAL COMPOSITION
CHEMICAL PROPERTIES
COAL
COHERENT SCATTERING
DATA
DIFFRACTION
ELECTRON MICROSCOPY
ENERGY SOURCES
EXPERIMENTAL DATA
FOSSIL FUELS
FOULING
FUELS
INFORMATION
LIGNITE
MATERIALS
MELTING
MICROSCOPY
MINERALS
NUMERICAL DATA
PHASE TRANSFORMATIONS
RESIDUES
SCATTERING
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE DEPENDENCE
X-RAY DIFFRACTION