A Combined Raman Spectroscopic and Thermogravimetric Analysis Study on Oxidation of Coal with Different Ranks

Table 1

Main coal quality indexes of coal samples.

Coal quality parameters	Samples
	Lignite	Bituminous coal	Anthracite
Analysis (%)
Moisture	17.75	4.44	5.06
Ash	20.86	21.59	16.55
Volatile matter	36.22	30.74	5.20
Fixed carbon	25.16	43.23	73.18
Hydrogen (%)	3.85	4.37	2.29
Heat of combustion (MJ kg^−1)	21.18	25.47	27.36