Quantitative evaluation of minerals in lignites and intraseam sediments from the Achlada Basin, Northern Greece
- Institute for Solid Fuels Technology and Applications, Athens (Greece). Centre for Research and Technology Hellas
Seven core samples (five lignite samples and two intraseam nonlignite rock samples) from the Achlada open-cut mine in northern Greece were characterized by X-ray diffraction (XRD) and X-ray fluorescence (XRF) techniques. Quantitative evaluation of the mineral phases in each sample was made from the powder X-ray diffractograms using Siroquant commercial interpretation software, which is based on Rietveld principles. The main minerals in the low-temperature ash (LTA) ash of the lignites are kaolinite and illite, with bassanite and quartz in minor proportions. The nonlignite rock samples mainly consist of illite, mica (2M1), and kaolinite (poorly ordered), along with quartz, chlorite (ferroan), feldspar (albite), rutile, and dolomite. Oriented-aggregate XRD study further shows the presence of smectite, and interstratified illite/smectite (I/S), in the clay fractions of the lignite and rock samples, with the mineral matter of the lignites being richer in kaolinite, smectite, and I/S than in mineral matter of the nonlignite materials. The differences in mineralogy between the lignite and the rock materials probably reflect selective concentration of minerals in the original peat during deposition, combined with authigenic precipitation of minerals such as kaolinite in the peat deposit. Inferred chemical analyses derived from the XRD data show reasonably good correlations with chemical data obtained by direct ash analysis, especially if the smectite and I/S are taken into account. This provides a link between mineralogical and chemical studies that may be valuable in evaluating the behavior of the lignite under different utilization conditions. 27 refs., 4 figs., 6 tabs.
- OSTI ID:
- 21187117
- Journal Information:
- Energy and Fuels, Vol. 23, Issue 4; ISSN 0887-0624
- Country of Publication:
- United States
- Language:
- English
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