Overview
ISO 3262-13:2023 - "Extenders - Specifications and methods of test - Part 13: Natural quartz (ground)" specifies requirements and test methods for ground natural quartz used as an extender (filler). The second edition updates test references (for example ISO 8130-13 for particle size analysis) and replaces the 1997 edition. The standard covers composition limits, physical parameters, sampling, a gravimetric determination of silica content and the minimum information required in a test report.
Keywords: ISO 3262-13:2023, natural quartz, ground quartz, extenders, specifications and methods of test, silica content, particle size distribution, quality control.
Key topics and technical requirements
- Grades and composition
- Two grades (A and B) with minimum quartz and SiO2 content: Grade A 97% and Grade B 80% (by mass) verified by X‑ray diffraction or X‑ray fluorescence/gravimetric methods.
- Physical limits (essential)
- Residue on sieve (63 µm and 45 µm) - limits to be agreed between parties; 63 µm example max 0.1% shown.
- Matter volatile at 105 °C: max 0.3% (ISO 787-2)
- Loss on ignition: max 0.5% (ISO 3262-1)
- Matter soluble in water (hot extraction): max 0.2% (ISO 787-3)
- pH (aqueous suspension): 5.5 to 9 (ISO 787-9)
- Conditional requirements
- Particle size distribution (instrumental) - ISO 8130-13 (laser diffraction)
- Oil absorption (ISO 787-5), colour, lightness, resistivity of aqueous extract (ISO 787-14)
- Sampling and test reporting
- Sampling according to ISO 15528.
- Test reports must identify the product, reference ISO 3262-13:2023, present results and methods, note deviations or anomalies, and give test dates.
Silica determination (brief)
The standard specifies a gravimetric procedure for silica content involving ignition, treatment with sulfuric and hydrofluoric acids, repeat ignition and weighing to calculate SiO2 mass fraction. (Refer to Clause 6 of ISO 3262-13:2023 for the detailed test method and safety considerations.)
Applications and users
- Manufacturers and suppliers of extenders and mineral fillers
- Paints, coatings and plastics manufacturers specifying fillers for formulations
- Quality control and analytical laboratories performing compliance testing
- Procurement/specification engineers and regulatory bodies assessing material conformity
Practical uses include incoming material inspection, supplier qualification, product specifications for coatings/resins, and R&D when selecting or comparing ground quartz extenders.
Related standards
For full test procedures, limits and safety details consult ISO 3262-13:2023.