Overview
ISO 602:2025 - Coal - Determination of mineral matter specifies a laboratory method to determine the mineral matter content of all types of coal, including brown coals and lignites. The fourth edition updates apparatus and reporting requirements and provides a reproducible acid-extraction and ash-based calculation to quantify inorganic constituents retained after partial demineralization.
Key topics and technical requirements
- Scope: Applicable to all coal types; results expressed on a dry basis.
- Principle: Partial demineralization by sequential treatment with hydrochloric acid (HCl) and hydrofluoric acid (HF) while preserving coal substance; measure mass loss, ash the residue, determine iron and chlorine contributions, and correct for acid absorption and hydrated mineral components.
- Reagents & safety: Analytical-grade HCl and HF required. HF and concentrated HCl are highly hazardous - use appropriate PPE and fume control.
- Apparatus: Acid-resistant labware (PVC recommended), 200 ml beakers, quantitative filter paper with sintered alumina filter plate, balance (0.1 mg), vacuum oven, filter flask, thermometer pocket and stirrer.
- Sample preparation: Analysis sample ground to pass a 200 µm sieve; air-drying or controlled drying (105–110 °C alternative) to laboratory moisture equilibrium as per ISO 11722 / ISO 5068-2.
- Procedure highlights: Typical test uses ~6 g sample, sequential HCl and HF treatments at 55–60 °C with timed stirring and filtration, extensive hot-water washing, vacuum drying at 50 °C (~1.5 h) and subsequent weighing. Ash, moisture, total iron (from ash) and chlorine in the extracted coal are measured to complete calculations.
- Calculation & corrections: Mineral matter M is calculated from mass loss, ash of extracted coal, chlorine (HCl equivalent), pyrite content (from iron oxide), and corrections (factors 1.5 for pyrite, 1.1 for hydrated alumino-silicates). A mineral-matter factor F = M / A (A = ash percentage) is provided.
- Precision: Repeatability (same lab, duplicate runs) maximum difference 0.4% absolute; inter-laboratory reproducibility not established.
Applications and users
ISO 602:2025 is used by:
- Industrial and commercial testing laboratories performing coal quality analysis
- Coal producers and fuel suppliers for specification and quality control
- Power stations and coking plants to assess ash-forming mineral content and combustion behavior
- Environmental and research organizations studying mineral-derived emissions or beneficiation processes
- Regulators and standards bodies requiring harmonized coal analysis methods
Keywords: ISO 602:2025, coal mineral matter determination, coal analysis, hydrofluoric acid, hydrochloric acid, mineral matter, ash, brown coal, lignite.
Related standards
For implementation, consult the full ISO 602:2025 text for exact procedural parameters, safety precautions and reporting requirements.
