| Acid conc., M | Extraction Efficiency, % | ||
| Cu | Co | Ni | |
| 1 | 17.8 | 25.5 | 24.7 |
| 3 | 47.9 | 55.2 | 60.5 |
| 5 | 77.2 | 82.2 | 82.4 |
| 7 | 92.5 | 94.6 | 96.0 |
| 9 | 90.7 | 95.0 | 94.8 |