Geologic Distribution: Cerium is the most abundant of the REE in West Virginia coals and is found in the minerals monazite and allanite 1. Monazite was found in trace amounts in 22 of 24 coal samples examined using scanning electron microscopy (SEM) in an unpublished study by the WVGES. Monazite is probably present in most West Virginia coals in minor amounts, thus explaining a lack of stratigraphic and geographic distribution trends in Ce abundance. Cerium averaged 16.88 ppm in West Virginia coals, and statistically correlated with other REE and elements associated with ash yield. The highest correlations were with elements in monazite especially lanthanum (La) and thorium (Th) and less so with yttrium (Y), neodymium (Nd), dysprosium (Dy) and gadolinium (Gd). Cerium also correlated with other REE, such as samarium (Sm), europium (Eu), ytterbium (Yb), lutetium (Lu) and terbium (Tb) on a whole coal basis. Because monazite is a detrital mineral in coal, cerium also correlated somewhat with ash yield, and the ash-related elements chromium (Cr), scandium (Sc), hafnium (Hf), lithium (Li), tantalum (Ta), vanadium (V) and lead (Pb).
Economic Impact: Cerium in coal should have no economic impact on coal use. The primary source of cerium is monazite mined from beach sands 1. Cerium is used in the manufacture of cigarette lighters, incandescent mantles in gas lights, as a catalyst in self-cleaning ovens, a catalyst in petroleum refining and as a polishing compound 1.
Environmental Impact: Generally the environmental impact of rare earth elements are little understood, and the contribution of cerium to the atmosphere during coal combustion is likely too low to be regarded as harmful 2.
References:
1. CRC
Handbook of Chemistry and Physics
2. Swaine,
D.J., (1990)
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