Overview
ISO 2596:2006 specifies standardized test methods for the determination of hygroscopic moisture in analytical samples of iron ores. The standard defines four accepted techniques - gravimetric, Karl Fischer volumetric, Karl Fischer coulometric, and mass-loss methods - for reporting moisture on a dried-sample basis. ISO 2596:2006 applies to iron ore types where direct determination of hygroscopic moisture is required (for example, processed ores containing metallic iron, ores with sulfur > 0.2% mass fraction, or ores with combined water > 2.5% mass fraction) and covers a hygroscopic moisture concentration range of 0.05% to 4.5% mass fraction.
Key topics and technical requirements
- Four test methods:
- Method 1 - Gravimetric: moisture evolved at 105 °C ± 2 °C in a drying tube with dry nitrogen sweep (100–200 ml/min); evolved water collected in an absorption tube (e.g., anhydrous magnesium perchlorate) and quantified by mass increase.
- Method 2 - Karl Fischer volumetric: titration-based determination following ISO Karl Fischer practices.
- Method 3 - Karl Fischer coulometric: high-sensitivity coulometric titration for low moisture levels.
- Method 4 - Mass-loss: direct determination by loss of mass on drying under specified conditions.
- Sampling and sample preparation: provisions for laboratory sampling and preparation of test portions to ensure representative, reproducible results.
- Apparatus and reagents: e.g., use of anhydrous magnesium perchlorate as desiccant, aluminium calcium silicate molecular sieves (dried at 400 °C for 4 h) and requirements to control background moisture and blank determinations.
- Performance range: methods are validated for the 0.05–4.5% hygroscopic moisture range; procedures include system checks, blank and check tests, and calculations for moisture content and correction of analytical test-portion mass.
Applications and users
ISO 2596:2006 is intended for:
- Metallurgical and mining laboratories performing chemical analysis of iron ores.
- Quality control and analytical chemists calculating constituents on a dry-sample basis.
- Processing plants and direct reduced iron (DRI) producers where moisture affects downstream calculations and product specification.
- Situations where standard drying of samples may give erroneous results due to ore type (e.g., high sulfur, high combined water, or metallic iron content).
Using ISO 2596:2006 ensures consistent, comparable moisture results across labs and supports accurate chemical constituent reporting on a dry basis.
Related standards
- ISO 760 - Determination of water - Karl Fischer method (general guidance)
- ISO 3082 - Iron ores - Sampling and sample preparation procedures
- ISO 3087, ISO 7764 - referenced for related reporting or alternate procedures
Keywords: ISO 2596:2006, iron ores, hygroscopic moisture, moisture determination, Karl Fischer, gravimetric method, mass-loss method, analytical samples.