The changes of the carbon stacking structure in caking and non-caking coals during heat-treatment were evaluated using an X-ray diffraction technique (STAC-XRD: Standard Analysis of Coal-by X Ray Diffraction). The thermal plasticity of caking coal influenced the development of the stacking structure during heat-treatment. The analysis of P_s (fraction of stacking structure) suggested that the carbon stacking structure in raw coal was degraded with the release of volatile components at 400-600℃, and was developed again at over 600℃.
