Table 1 Elemental composition of the ion-adsorption clay and its size fractions: S1 (< 0.25 mm), S2 (0.25–0.5), S3 (0.5–2 mm).
Sample Name | Ionic clay—as-is | S1 | S2 | S3 |
|---|---|---|---|---|
Particle Size | – | < 0.25 mm | 0.25–0.5 mm | 0.5–2 mm |
BET Surface area (m2/g) | 30.8 | 32.5 | 24.7 | 24.9 |
Mass fraction (%) | 100 | 48 | 15 | 37 |
Element | ppm (mg/kg) | ppm | ppm | ppm |
Sc | 28.8 | 30.3 | 21.1 | 22.7 |
Y | 898.5 | 1262.4 | 887.6 | 431.6 |
La | 464.7 | 699.6 | 361.6 | 210.2 |
Ce | 816.0 | 1139.2 | 656.7 | 496.5 |
Pr | 100.5 | 154.8 | 77.0 | 46.8 |
Nd | 423.2 | 644.4 | 334.1 | 196.1 |
Sm | 68.9 | 104.5 | 56.0 | 32.9 |
Eu | 2.3 | 3.4 | 2.0 | 1.0 |
Gd | 78.9 | 111.4 | 68.6 | 37.6 |
Tb | 10.7 | 14.7 | 9.3 | 5.2 |
Dy | 120.9 | 173.7 | 118.5 | 64.5 |
Ho | 24.7 | 34.7 | 25.1 | 13.2 |
Er | 79.6 | 112.5 | 81.8 | 43.6 |
Tm | 10.6 | 14.9 | 10.8 | 6.0 |
Yb | 63.0 | 87.6 | 63.0 | 38.4 |
Lu | 13.0 | 15.8 | 11.9 | 6.9 |
Total REEs | 3204.0 | 4603.9 | 2785.3 | 1653.4 |
Th | 152.1 | 234.7 | 118.7 | 83.0 |
U | 1.6 | 2.4 | 1.3 | 1.0 |
wt% | wt% | wt% | wt% | |
Fe | 8.3 | 9.2 | 7.6 | 6.9 |
Al | 8.4 | 12.5 | 6.8 | 3.4 |
Si | 31.5 | 24.0 | 35.1 | 40.4 |
P | 0.2 | 0.2 | 0.2 | 0.2 |
