Table 8 The summary of the main procedures developed
Leaching process | REEs concentration, mg/kg | % Total REEs | References | ||||
|---|---|---|---|---|---|---|---|
Y | La | Ce | Pr | Er | |||
3 cycle 3.0 M nitric acid | 11.9 | 85.9 | 159.2 | 10.7 | 49.3 | 66.0 | [14] |
3 cycle citric acid | 8.3 | 95.6 | 180.2 | 17.7 | 59.3 | 83.4 | [13] |
Alkali treatment + 1 cycle nitric acid | 8.8 | 95.8 | 206.6 | 19.5 | 70.7 | 75.1 | This work |
Alkali treatment + 1 cycle citric acid | 13.9 | 100.7 | 215.3 | 20.9 | 69.4 | 87.4 | This work |