Application of Scanning Electron Microscopy and Automated Image Analysis for Characterization of Mineral Matter in Coal

摘要

Automated Image Analysis (AIA) in conjunction with Scanning Electron Microscopy (SEM) and energy-dispersive x-ray analysis (EDX) constitutes a very powerful tool for the in-situ characterization of mineral matter in coal. This AIA-SEM technique provides detailed information on size, shape, composition, and association of mineral phases with the coal matrix. In addition, the in-situ capability of the SEM and EDX techniques is augmented by computer control to provide quantitative information on the distribution of the mineral species present in coal. The AIA-SEM technique has been aplied to many samples of bituminous and sub-bituminous coals to characterize their mineral content. Some of the fundamental aspects of AIA as an analytical technique for coal are described. The description includes construction of suitable chemistry files for mineral phase definitions, the numbers of particles needed to develop reliable results and adequate reproducibility between samples, difficulties arising from a wide spead in the minimum and maximum particle sizes, comparison of AIA results with other characterization methods as x-ray diffraction and Fourier transform infrared (FTIR) analyses, the problems encountered in quantitation, such as the artificial enrichment of pyrite content due to instrumental factors. 8 refs., 6 tabs. (ERA citation 10:043653)