| Leaching agent | Dissolution (%) | SiO2 grade (%) | ||
| Acid | Concentration (mol/L) | Fe | Al2O3 | |
| HCl | 2.00 | 39.8 | 39.0 | 96.5 |
| HCl | 5.00 | 54.7 | 25.2 | 96.2 |
| H2SO4 | 5.00 | 27.8 | 15.8 | 95.2 |
| H2SO4 | 2.00 | 26.4 | 8.7 | 94.7 |
| C6H8O7 | 1.00 | 40.7 | 23.8 | 96.0 |
| (COOH)2∙2H2O | 0.70 | 33.9 | 18.3 | 95.6 |