SELECTIVE CHEMICAL MAPPING OF COAL MICROHETEROGENEITY BY SCANNING-TRANSMISSION X-RAY MICROSCOPY

Scanning transmission X-ray microscopy (STXM) was used to spatially map aromatic and aliphatic carbon distributions in ultramicrotomed coal thin sections at the submicron level. In addition, microfocus X-ray absorption spectra recorded at the carbon K absorption edge allowed analysis of the variations in fundamental chemistry at maceral interfaces and within maceral boundaries. The ability of STXM to map the chemical composition of coal to this resolution has provided rich detail into the chemical and physical heterogeneity of macerals and of submaceral domains, as well as to the identification of microfine mineral particles that are present.