Research Article
Kinetic Analysis of Aluminum Extraction from Ethiopian Kaolinite Using Hydrochloric Acid
Table 2
The regression correlation coefficients and rate constants for extraction of aluminum at various acid concentrations from 2 to 5 M.
| | Model | Rate equation | The regression correlation coefficients and rate constants (ki) for extraction of aluminum at various acid concentrations from 2 to 5 M | | 2 M | 3 M | 4 M | 5 M | | R2 | ki | R2 | ki | R2 | ki | R2 | ki |
| | Shrinking core | | 0.991 | 1.22 × 10−3 | 0.993 | 1.72 × 10−3 | 0.983 | 2.64 × 10−3 | 0.992 | 2.87 × 10−3 | | 0.984 | 2.05 × 10−3 | 0.983 | 2.64 × 10−3 | 0.972 | 3.36 × 10−3 | 0.974 | 3.61 × 10−3 | | 0.970 | 1.12 × 10−3 | 0.971 | 1.81 × 10−3 | 0.972 | 3.37 × 10−3 | 0.974 | 3.58 × 10−3 | | Pseudohomogeneous | | 0.974 | 4.36 × 10−3 | 0.972 | 6.24 × 10−3 | 0.964 | 1.13 × 10−2 | 0.963 | 1.33 × 10−2 | | 0.981 | 8.75 × 10−3 | 0.973 | 1.60 × 10−2 | 0.863 | 5.38 × 10−2 | 0.824 | 6.92 × 10−2 | | Avrami | | 0.973 | 3.17 × 10−2 | 0.952 | 3.27 × 10−2 | 0.953 | 3.40 × 10−2 | 0.950 | 3.44 × 10−2 | | Model parameter (n) | 0.623 | | 0.704 | | 0.803 | | 0.812 | |
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2LOI: loss on ignition from TGA analysis.
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