Table 2.
Element analysis of samples.
| Kind | 1 |
2 |
3 |
4 |
5 |
|||||
|---|---|---|---|---|---|---|---|---|---|---|
| CEN | PER | CEN | PER | CEN | PER | CEN | PER | CEN | PER | |
| C | 38.40 | 58.76 | 35.41 | 46.86 | 23.26 | 46.51 | 40.70 | 71.07 | 33.52 | 41.16 |
| O | 49.60 | 35.51 | 49.93 | 42.22 | 50.42 | 38.69 | 46.39 | 26.73 | 48.82 | 45.26 |
| Ca | 5.43 | 2.66 | 7.75 | 5.96 | 14.73 | 8.05 | 6.33 | 0.74 | 8.40 | 7.21 |
| P | 4.89 | 2.27 | 6.19 | 4.41 | 10.63 | 6.06 | 5.71 | 0.67 | 7.58 | 5.73 |
| Na | 0.60 | 0.33 | 0.33 | 0.32 | 0.48 | 0.39 | 0.29 | 0.21 | 0.50 | 0.19 |
| Mg | 0.19 | 0.07 | 0.16 | 0.07 | 0.30 | 0.12 | 0.32 | 0.02 | 0.60 | 0.30 |
| Si | 0.75 | 0.33 | - | 0.04 | - | - | - | 0.08 | 0.47 | 0.09 |
| S | 0.03 | 0.01 | 0.15 | 0.05 | 0.06 | 0.03 | 0.19 | 0.42 | - | - |
| Cl | 0.07 | 0.06 | 0.10 | 0.06 | 0.13 | 0.15 | 0.07 | 0.05 | 0.11 | 0.05 |
| K | 0.04 | - | - | - | - | - | - | - | 0.02 | - |
Relative content was calculated based on atomic number (%).
Abbreviations: CEN: center, PER: periphery, C: carbon, O: oxygen, Ca: calcium, P: phosphorus, Na: sodium, Mg: magnesium, Si: silicon, S: sulphur, Cl: chlorine, K: potassium.