Geochemistry and mineralogy of Greek lignites from the Ioannina Basin

Journal Article · Sat Feb 01 04:00:00 EST 1997 · Energy Sources

DOI:https://doi.org/10.1080/00908319708908837· OSTI ID:455411

Gentzis, T ^[1]; Goodarzi, F ^[2]; Foscolos, A E ^[3]

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1. Alberta Research Council, Edmonton, Alberta (Canada)
2. Geological Survey of Canada, Calgary, Alberta (Canada). Inst. of Sedimentary and Petroleum Geology
3. Technical Univ. of Crete, Chania (Greece). Dept. of Mineral Resources Engineering

Mineralogical and elemental composition of 26 lignites/lignitic shales and their ashes from the Ioannina Basin were examined using X-ray diffraction, X-ray fluorescence, and instrumental neutron activation analysis. Mineralogy consists of quartz, 2:1 interstratified layer silicates, kaolinite, and gypsum. Illite, calcite, amphiboles, feldspars, and pyrite are the minor minerals in the samples. The major oxides SiO{sub 2}, Al{sub 2}O{sub 3}, Fe{sub 2}O{sub 3}, TiO{sub 2}, and K{sub 2}O show an enrichment in the upper lignite-bearing interval within the succession, CaO shows the exact reverse trend, and Na{sub 2}O and MgO do not show any trends. Arsenic in the samples ranges from 2 to 46 ppm, Br from 10 to 25 ppm, Cl from 61 to 278 ppm, and Se from 2 to 14 ppm. Vertically, As content decreases from the shallower interval II to the deeper interval I. Within interval II, Cr and Br show a decrease from top to bottom. The concentration of Br and Cl is higher in the samples of low mineral matter, while the opposite is true for As. Laterally, there is an increase in Br and Cl from the northern to the central part of the basin, an increase of As in an eastern direction, and a decrease of Se in the same direction. Epigenetic processes related to high water table and subsurface water flow from the nearby phosphorite deposits are probably responsible for the high concentration of U, Mo, Sb, and possibly, V. The enrichment of Se is due to leaching from gypsum and/or anhydrite beds in the area. The rare earth elements follow variations in the low-temperature ash, but more specifically, the light REEs tend to mimic variations in Th and Al{sub 2}O{sub 3} concentration, and the heavy REEs follow the TiO{sub 2} variation.

• Sponsoring Organization: USDOE
• OSTI ID: 455411
• Journal Information: Energy Sources, Journal Name: Energy Sources Journal Issue: 2 Vol. 19; ISSN 0090-8312; ISSN EGYSAO
• Country of Publication: United States
• Language: English

Related Subjects

01 COAL, LIGNITE, AND PEAT
ASH CONTENT
COAL DEPOSITS
GEOCHEMISTRY
GREECE
LIGNITE
MINERALOGY
MINERALS