Pore morphology in pressurized lignite coal: A small angle x-ray scattering investigation

The morphological changes in lignite coal at two different pressures, using small angle x-ray scattering, have been investigated. All the scattering p rofiles are interpreted in terms of surface fractal morphology. It is obser ved that the surface fractal dimension does not change appreciably under th e experimental pressure range, while the volume of micro-cracks and inter-p article pore space is reduced with increasing pressure. By and large, the c onstant value of the surface fractal dimension of all the specimens, as cal culated from the scattering profiles, indicates that the roughness on the p ore coal interface remains almost unaffected under the experimental pressur e range. The validity of single scattering approximation for this experimen t has also been confirmed by the observation of the identical nature of the small angle scattering profiles with respect to change of wave lengths, na mely, 0.154 nm. (Cu K-alpha) and 0.072 nm (Mo K-alpha), of the probing radi ation. (C) 2001 Kluwer Academic Publishers.