Relationship between coking coal quality and its micro-Raman spectral characteristics

• Coking coal microstructure analyzed by micro-Raman spectroscopy.
• The G band FWHM and AG/AALL ratio correlate with the volatile matter content and the all maceral reflectance scan value.
• Micro-Raman analysis can be used for evaluation of the Vdaf content and Rscan value for coking coal.

Micro-Raman spectroscopy examination of 20 samples of coking coals (Rr = 0.84–1.43%) was performed. Spectral parameters were correlated with the basic rank and technological properties of coals.The G band FWHM and the AG/AALL ratio decrease with the volatile matter content (Vdaf) decrease and the all maceral reflectance scan (Rscan) value increase. The correlations between these parameters are stronger than those, between the G band FWHM and the AG/AALL ratio, and the mean random vitrinite reflectance (Rr). Coking properties are weakly related to the Raman spectral characteristics of coal. Based on the Raman parameters G band FWHM and the AG/AALL ratio, it may be possible to evaluate the volatile matter content (Vdaf) and the all maceral reflectance scan (Rscan) value for coking coals.