Description of Index | Spec. |
| Miss fraction of sulfur, %: not less than | 99.91 |
| Mass faction of ash, % not less than | 0.008 |
| Mass fraction of organic compounds, %, not more than | 0.008 |
| Mass faction of acids converted to sulfuric acid, %, not more than | 0.0015 |
| Mass fraction of moisture, %, not more than | 0.1 |
| Presence of mechanical impurities | Absent |