Overview
ISO 20360:2020 - "Brown coals and lignites - Determination of the volatile matter in the analysis sample: one furnace method" specifies a standardized laboratory procedure to measure volatile matter in brown coals and lignites. The method determines volatile matter as the mass loss (corrected for moisture) when a prepared analysis sample is heated out of contact with air at 900 °C for a defined time. The one-furnace method is designed for repeatable, reproducible results and aligns with other coal analysis methods.
Key topics and technical requirements
- Test principle: Loss in mass of an analysis sample heated out of contact with air at 900 °C for 7 minutes, corrected for moisture.
- Sample preparation: General analysis sample reduced to nominal top size 212 µm, pressed into cakes (1.0–1.5 cm thick, ≈1.0 cm diameter) and cut into pellets of about 3 mm side length.
- Furnace and temperature control: Electric furnace with a uniform temperature zone at 900 °C ±5 °C; furnace must regain 900 °C ±10 °C within 3 minutes after insertion of cold stand and crucibles.
- Crucible and lid: Glazed porcelain (or equivalent fused silica) crucible/lid with good seal; horizontal clearance between crucible and lid ≤ 0,5 mm. Proper lid fit is critical to exclude air and prevent oxidation.
- Instrumentation:
- Unsheathed thermocouple positioned midway between crucible base and furnace floor for temperature checks.
- Analytical balance with resolution ≥ 0,1 mg.
- Pellet presser capable of >100 kg force (examples in the standard show settings between 200–300 kg).
- Desiccator with fresh desiccant (magnesium perchlorate or silica gel) - note safety warning for magnesium perchlorate.
- Moisture determination: Conduct duplicate moisture tests concurrently (ISO 5068-2 referenced) so volatile matter can be corrected to dry basis.
- Precision and reporting: The standard includes clauses on repeatability and reproducibility limits and specifies required test report content.
Applications and users
ISO 20360:2020 is used by:
- Analytical laboratories performing routine coal quality testing
- Coal and lignite producers for product specification and quality control
- Power plants and utilities assessing fuel properties for combustion and emissions planning
- Research institutions studying coal behavior and thermal decomposition
- Regulators and procurement teams requiring standardized volatile matter data for contracts and compliance
Practical benefits include consistent volatile matter values for fuel characterization, improved comparability between laboratories, and guidance on sample handling to minimize oxidation.
Related standards
Keywords: ISO 20360:2020, volatile matter, brown coals, lignites, one furnace method, coal analysis, crucible, pellet presser, moisture correction.
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