Compression of Aggregates of Acid-Leached Coal Gangues: Implications for Coal Mine Backfill

Table 4

Main elements and compounds in granite before and after treatment with water and acidic solutions.

Sample name	Mass percentage of elements and compounds (%)
	SiO2	Al2O3	CO3	Fe2O3	K2O	CaO	MgO	TiO2	Na2O
Original gangue	56.08	23.38	9.72	4.397	2.06	1.53	1.15	0.869	0.606
SP 5–10 (7)	57.11	22.7	9	4.146	2.43	2	1.15	0.804	0.488
SP 5–10 (5)	54.55	22.45	10.9	4.238	3.24	1.95	1.13	0.793	0.517
SP 5–10 (3)	56.59	22.25	11.7	3.062	2.4	1.64	0.97	0.809	0.346
SP 10–15 (3)	56.72	23.87	9.44	3.697	2.03	1.77	0.986	0.849	0.448
SP 15–20 (3)	55.88	23.09	9.42	3.618	2.07	1.24	1.16	0.844	0.496