| Solid content (%) | NaOH (mol/L) | Temp. (˚C) | Time (h) | Dissolution (%) | SiO2 grade (%) | |
| Fe | Al2O3 | |||||
| 10 | 5.00 | 70 | 3 | 17.2 | 22.4 | 95.6 |
| 50 | 12.50 | 70 | 3 | 41.0 | 41.7 | 95.7 |
| 70 | 12.50 | 70 | 3 | 27.6 | 40.5 | 95.3 |
| 50 | 12.50 | 70 | 8 | 38.9 | 46.4 | 96.9 |
| 50 | 12.50 | 25 | 24 | 34.0 | 27.5 | 95.5 |