Overview
EN ISO 8840:2024 (identical to ISO 8840:2021) defines laboratory methods for determining the bulk density (grain density) of granular refractory materials with grain size greater than 2 mm. The standard specifies three liquid-displacement based procedures to measure the volume of a known mass of grains and calculate bulk density. Method 1 (mercury method with vacuum) is the reference technique. Methods 2 and 3 (arrested water absorption and vacuum method with spin dryer per ISO 5017) are provided as practical alternatives. The document also covers sampling, sample preparation and reporting conventions.
Key topics
- Scope and purpose: Measurement of grain/bulk density for granular refractories (>2 mm) by displacement methods.
- Three prescribed methods:
- Method 1 - Mercury method with vacuum (reference method).
- Method 2 - Arrested water absorption method (water displacement).
- Method 3 - Vacuum method with spin dryer option (according to ISO 5017).
- Principle: Determine volume by liquid displacement and calculate bulk density = mass/volume (includes closed pore volume within grains).
- Sampling and sample prep: Sampling in accordance with ISO 8656; sieve fractions to >2 mm, remove dust/loose particles (wash or air blow), and narrow grain-size distribution (recommended 3–4 mm) to improve reproducibility.
- Repeatability: At least three test samples are recommended; method-specific procedures for mass and volume determinations are described.
- Reporting: Results can differ by method and material; specify the method used when stating bulk density to avoid disputes.
Applications
- Quality control and incoming inspection for refractory manufacturers and suppliers.
- Product specification and acceptance testing for steelmaking, foundries, cement kilns, glass furnaces and other high-temperature industries using refractory aggregates and unshaped refractories.
- R&D and materials development where accurate grain-density data inform mix design, packing, porosity and thermal property calculations.
- Contractual testing and dispute resolution where a standardized reference method (Method 1) is required.
Who uses this standard
- Testing laboratories and certification bodies performing refractory material characterization.
- Materials and process engineers, production QA/QC teams, procurement specialists, and standards/technical committees involved in refractory product specification.
Related standards
- ISO 5017 - Dense shaped refractory products (vacuum/spin dryer option referenced).
- ISO 8656 - Sampling of refractory products and unshaped materials.
- ISO 383 and ISO 385-1 - Laboratory glassware referenced for apparatus requirements.
- EN 993-18:2002 - Superseded by EN ISO 8840:2024.
Keywords: EN ISO 8840:2024, ISO 8840, refractory materials, bulk density, grain density, granular refractory materials, mercury method, arrested water absorption, vacuum method, ISO 5017, sampling.