Table 3. Iron Oxide of Raw and Modified Kaolin Minerals^a.

		SiO2/Al2O3	Fe2O3 (% of all oxide)	Fe2O3 decreaseb	acid-leached Fe (mg/g)c
LRS_H	raw	1.54	0.56
	heat	1.40	0.52	7.31
	acid	1.51	0.51	8.73	0.59 ± 0.02
	acid-heat	1.44	0.45	19.79
LRS_HF	raw	1.90	6.07
	heat	1.69	5.22	14.09
	acid	1.97	1.48	75.67	24.42 ± 4.05
	acid-heat	1.94	1.34	77.89
LRS_HK	raw	1.42	0.4
	heat	1.34	0.34	14
	acid	1.40	0.3	26	0.78 ± 0.005
	acid-heat	1.35	0.26	35.75
LRS_HKF	raw	1.89	5.33
	heat	1.79	4.84	9.24
	acid	2.00	1.61	69.91	28.68 ± 3.26
	acid-heat	1.94	1.5	71.88
LRS_K	raw	1.40	0.57
	heat	1.15	0.45	20.42
	acid	1.23	0.46	19.01	0.31 ± 0.02
	acid-heat	1.17	0.42	26.58
LRS_KF	raw	1.47	3.74
	heat	1.33	3.24	13.47
	acid	1.49	1.34	64.12	14.22 ± 1.23
	acid-heat	1.38	1.32	64.81

^aFull XRF tabulating possible metal oxides is presented as Table S2.

^bRelative to the raw material.

^cQuantified directly by ICP-OES.