Mineral transformations during ashing and slagging of selected low-rank coals

Conference · Sun Jan 01 04:00:00 EST 1984

OSTI ID:5141881

Falcone, S K; Schobert, H H; Rindt, D K; Braun, S

The purpose of this study is to identify mineral transformations in low to high temperature ashes (125/sup 0/, 750/sup 0/, and 1000/sup 0/C) and slags (1300/sup 0/C) characteristic of lignites. The processes responsible for certain mineral transformation are also examined. Twelve low-rank coals were selected from the northern Great Plains and Gulf Coast. Nine North Dakota lignites, two Gulf Coast (Texas and Alabama) lignites, and one subbituminous coal from Montana were studied. The results of this study reflect the preliminary stage of investigation into the mineral phase transformations seen in low-rank coals. The original mineralogies of coals sampled do not vary a great deal. Quartz, kaolinite, pyrite, and bassanite are found in abundance in each LTA sample. Greater differences between samples are apparent at higher temperatures where complex alumino-silicates predominate. Perhaps this is a reflection of diffrences not so much in original mineral matter but in the total inorganic composition of the coal, specifically the presence of exchangeable alkali cations. The interactions of such organically-bound cations with crystalline inorganic phases in lignites account for differences in ashing and slagging behavior between coal samples. The processes responsible for most reactions identified are oxidation, dehydration, sulfur fixation, solid-state interactions, vaporization, and recrystallization. Isolating specific reactions occurring in a multi-component system is difficult at best. Understanding the thermodynamics of mineral transformations is a necessity and will be pursued in future study. In addition, future studies isolating mineral pairs to observe phase transformations at various temperatures will support or refute results presented here. 13 references, 2 tables.

• Research Organization: North Dakota Univ., Grand Forks (USA). Energy Research Center
• DOE Contract Number: FC21-83FE60181
• OSTI ID: 5141881
• Report Number(s): DOE/FE/60181-68; CONF-840614-45; ON: DE84009230
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
010600* -- Coal
Lignite
& Peat-- Properties & Composition
ALKALI METALS
ALKALINE EARTH METALS
ALUMINIUM
ASHES
BARIUM
BROWN COAL
CALCIUM
CARBONACEOUS MATERIALS
CHEMICAL COMPOSITION
COAL
COHERENT SCATTERING
DATA
DIFFRACTION
DRY ASHING
ELEMENTS
ENERGY SOURCES
EXPERIMENTAL DATA
FOSSIL FUELS
FUELS
HIGH TEMPERATURE
INFORMATION
IRON
LIGNITE
MAGNESIUM
MATERIALS
MEDIUM TEMPERATURE
METALS
MINERALOGY
NONMETALS
NUMERICAL DATA
POTASSIUM
RESIDUES
SCATTERING
SEMIMETALS
SILICON
SLAGS
SODIUM
SUBBITUMINOUS COAL
SULFUR
TITANIUM
TRANSITION ELEMENTS
VERY HIGH TEMPERATURE
X-RAY DIFFRACTION