Investigation on the Microstructure Evolution of High-Rank Coal from Xinhua County, Hunan, China

Different degrees of crystallite graphite can be formed as magma intrusions into coal measure strata. This study summarizes the results of microstructure and spectroscopy analyses performed to evaluate the macromolecule evolution of the graphitization series of coal samples from Xinhua County in Hunan Province, South China. The samples exhibited progressive evaluation in the X-ray diffraction patterns. Raman parameters showed a clear change at the D and G bands. The morphology of crystallite graphite became orderly. Some structures similar to carbon nanotubes appeared during the graphitization. During the metamorphism process from anthracite to graphite, the size of single-layer graphene sp(2) planar domain increased, and the carbon atom in crystal lattice sites fitted in order gradually.