Table 5. Washability of Coal.

samples	setting	δ ± 0.1 content/%	class
YQ9-BC	ash of 10%	28.66	general difficulty
	sulfur of 2%	8.79	easy
	sulfur of 1%	72.56	extremely difficult
YQ9-SB	ash of 10%	64.81	extremely difficult
	sulfur of 2%	14.26	middle
	sulfur of 1%	66.68	extremely difficult
YQ15-BC	ash of 5%	69.95	extremely difficult
	sulfur of 2%	88.08	extremely difficult
GZ9-DC	ash of 10%	67.54	extremely difficult
	sulfur of 1%	23.34	general difficulty
GZ9-SD	ash of 10%	40.57	extremely difficult
	sulfur of 1%	64.73	extremely difficult
GZ9-BC	ash of 10%	2.8	easy
	ash of 5%	18.55	middle
	sulfur of 1%	6.73	easy