Kinetic Analysis of Aluminum Extraction from Ethiopian Kaolinite Using Hydrochloric Acid
Table 1
The regression correlation coefficients and rate constants for aluminum extraction at various solid-to-liquid ratios from 0.050 to 0.125 g·mL−1.
Model
Rate equation
The regression correlation coefficients and rate constants (ki1) for extraction of aluminum at various solid-to-liquid ratios from 0.050 to 0.125 g·mL−1
0.050
0.075
0.100
0.125
R2
ki
R2
ki
R2
ki
R2
ki
Shrinking core
0.993
3.09 × 10−3
0.994
2.94 × 10−3
0.984
2.81 × 10−3
0.983
2.36 × 10−3
0.954
3.71 × 10−3
0.969
3.65 × 10−3
0.974
3.52 × 10−3
0.982
3.28 × 10−3
0.978
4.16 × 10−3
0.976
4.03 × 10−3
0.967
3.99 × 10−3
0.965
3.50 × 10−3
Pseudohomogeneous
0.975
1.57 × 10−2
0.971
1.46 × 10−2
0.964
1.37 × 10−2
0.955
1.12 × 10−2
0.936
3.76 × 10−2
0.901
5.87 × 10−2
0.893
8.55 × 10−2
0.873
1.09 × 10−1
Avrami
0.974
3.26 × 10−2
0.962
3.37 × 10−2
0.961
3.49 × 10−2
0.960
3.58 × 10−2
Model parameter (n)
0.773
0.814
0.832
0.841
1For surface chemical reaction controlled, ki = kc; for diffusion through liquid controlled, ki = kf; and, for diffusion though product layer controlled , ki = kd.
