Overview
ISO 21283:2018 describes a standardized test method for determining the specific surface area (Blaine surface area, BSA) of iron ores, using the manual Blaine air‑permeability apparatus. The method applies to pellet feeds with a specific surface area in the range 400 cm2/g to 2 500 cm2/g. It provides a validated laboratory procedure for measuring fineness by drawing ambient air through a compressed bed of sample and relating airflow to surface area.
Key topics and requirements
- Principle: Air is drawn through a compacted test portion; the airflow rate and pressure drop are used to calculate Blaine specific area (BSA).
- Scope: Applicable to iron ore pellet feeds (merchant pellet feed materials) within the specified BSA range.
- Sampling & sample prep: Follows ISO 3082 sampling guidance; oven‑dry test samples at 105 °C ± 5 °C to constant mass, disaggregate and sieve (minus 1.0 mm and 0.150 mm fractions), and prepare at least four test portions.
- Apparatus: Manual Blaine permeability cell assembly including permeability cell, perforated disc, plunger, manometer (U‑tube), filter paper, timer, precision balance (0.001 g), thermometer, funnel and caliper. The standard gives specifications and tolerances for key parts.
- Calibration: Determine the equipment constant (K) using a certified reference material (CRM) with known density, porosity and specific surface. Cell volume can be measured by caliper or (if used) mercury - with explicit safety warnings about mercury handling.
- Procedure & calculations: Details for compacting test beds, timing permeability tests, calculating Blaine specific area (BSA), repeatability criteria and acceptance of results.
- Safety note: The document cautions about hazardous materials and safe laboratory practice when performing tests.
Applications and users
ISO 21283:2018 is used for:
- Quality control in mining, pellet production and beneficiation plants.
- Contract specifications and commercial trading of pellet feed where BSA is a contractual attribute.
- Research and development on iron ore grind/fineness and pelletization behaviour.
Typical users include laboratory technicians, metallurgical QA/QC teams, pellet producers, mine laboratories, trade inspectors and standards organizations.
Related standards
- ISO 3082 - Iron ores: Sampling and sample preparation procedures
- ISO 11323 - Iron ore and direct reduced iron: Vocabulary
- ISO 12154 - Density determination by gas pycnometry (skeleton density)
Keywords: ISO 21283:2018, Blaine, specific surface area, iron ores, pellet feed, air‑permeability apparatus, permeability cell, calibration, CRM, BSA.