Overview
ISO 12900:2018 - Hard coal - Determination of abrasiveness - defines a laboratory method to quantify the abrasiveness of hard coal. The standard measures metal loss from four standardized steel blades rotated in a prepared coal charge under controlled conditions, producing a reproducible abrasiveness index expressed in milligrams of metal lost per kilogram of coal. The method is intended for ranking coals and providing initial empirical estimates of wear in various coal-handling and pulverizing systems.
Key topics and requirements
- Test principle: abrasion is determined from the mass loss of four steel blades after a defined number of revolutions with a 2 kg test portion of coal.
- Apparatus and components:
- Standard reference blades with Vickers hardness 160 ± 15 (ISO 6507-1 referenced).
- Mill mortar and removable quadrant assembly, with specified clearances and dimensions.
- Drive system with controlled speed and automatic cut-off (test run to 12 000 revolutions at the prescribed quadrant speed).
- Precision balances for blade (0.1 mg) and test portion weighing.
- Sample preparation:
- Nominal top size: 6.7 mm (minus 6.7 mm fraction used).
- Fines content: not more than 30 %