Characterization and Optimization of Calcination Process Parameters for Extraction of Aluminum from Ethiopian Kaolinite

Table 3

CCD experiments for optimization of calcination parameters on responses: degree of conversion of kaolinite dehydroxylation reaction (Y) and extracted aluminum (Z).

Run	Temperature (°C)	Time (min)	Particles size (μm)	Initial mass, mo	Final mass, mf	Y (The dehydroxylation reaction of kaolinite degree of conversion determined from mass loss during calcination of kaolinite samples and TGA LOI value.)	Z (The extracted aluminum content determined from UV-vis standard solutions calibration curve.) (% w/w)
1	600	120	106	15 ± 0.02	13.38 ± 0.02	0.963	66.48
2	565	150	250	15 ± 0.01	13.43 ± 0.01	0.936	63.64
3	650	150	250	15 ± 0.01	13.37 ± 0.01	0.970	70.26
4	650	150	250	15 ± 0.01	13.37 ± 0.01	0.968	70.19
5	700	120	106	15 ± 0.02	13.34 ± 0.01	0.989	70.25
6	650	150	250	15 ± 0.01	13.37 ± 0.01	0.971	70.02
7	700	120	355	15 ± 0.01	13.38 ± 0.02	0.965	66.62
8	650	150	250	15 ± 0.01	13.37 ± 0.01	0.969	70.22
9	734	150	250	15 ± 0.01	13.36 ± 0.01	0.976	68.36
10	700	180	106	15 ± 0.02	13.34 ± 0.01	0.991	71.27
11	600	180	106	15 ± 0.01	13.37 ± 0.01	0.969	67.81
12	650	150	250	15 ± 0.01	13.37 ± 0.01	0.970	70.23
13	600	120	355	15 ± 0.02	13.41 ± 0.01	0.947	64.39
14	650	150	63	15 ± 0.01	13.34 ± 0.01	0.990	71.13
15	700	180	355	15 ± 0.02	13.37 ± 0.01	0.971	67.64
16	650	150	250	15 ± 0.01	13.37 ± 0.02	0.969	70.21
17	650	200	250	15 ± 0.01	13.36 ± 0.01	0.974	69.23
18	600	180	355	15 ± 0.01	13.40 ± 0.01	0.952	65.73
19	650	100	250	15 ± 0.01	13.38 ± 0.02	0.964	67.55
20	650	150	500	15 ± 0.01	13.39 ± 0.02	0.961	63.83