TABLE 1.
Summary of the variation in particle size and coal chemistry between the 19 samples
| Mean | Minimum | Maximum | SD | |
|---|---|---|---|---|
| Proximate analysis (air‐dried basis) | ||||
| Moisture (%) | 5.31 | 2.30 | 10.00 | 2.30 |
| Ash (%) | 42.36 | 8.53 | 89.38 | 25.89 |
| Volatile matter (%) | 18.27 | 4.53 | 27.20 | 5.61 |
| Fixed carbon (%) | 34.06 | 0.69 | 64.53 | 21.08 |
| Calorific value (MJ/kg, raw) | 17.27 | 0.50 | 31.80 | 9.99 |
| Ultimate analysis (wt%, dry ash‐free basis) | ||||
| Carbon | 42.88 | 2.48 | 77.78 | 23.88 |
| Hydrogen | 2.77 | 0.93 | 4.51 | 1.04 |
| Nitrogen | 0.93 | 0.05 | 1.55 | 0.50 |
| Sulphur | 0.32 | 0.03 | 0.78 | 0.20 |
| Oxygen | 5.44 | 1.66 | 8.22 | 1.73 |
| Inorganic constituents (wt%, air‐dried basis) | ||||
| SiO2 | 28.77 | 3.81 | 64.88 | 18.78 |
| Al2O3 | 9.40 | 1.69 | 25.46 | 6.30 |
| Fe2O3 | 1.42 | 0.15 | 4.77 | 1.37 |
| CaO | 0.38 | 0.05 | 0.94 | 0.23 |
| MgO | 0.42 | 0.06 | 1.24 | 0.42 |
| Na2O | 0.28 | 0.01 | 1.23 | 0.37 |
| K2O | 0.81 | 0.02 | 3.54 | 0.95 |
| TiO2 | 0.32 | 0.08 | 0.72 | 0.20 |
| Mn3O4 | 0.01 | 0.00 | 0.05 | 0.01 |
| SO3 | 0.29 | 0.00 | 0.96 | 0.27 |
| P2O5 | 0.05 | 0.00 | 0.27 | 0.08 |
| BaO | 0.10 | 0.00 | 1.38 | 0.32 |
| SrO | 0.01 | 0.00 | 0.04 | 0.01 |
| ZnO | 0.00 | 0.00 | 0.01 | 0.00 |
| Particle size (µm) | 0.11 | 0.10 | 0.12 | 0.01 |