Overview
EN ISO 3262-14:2023 (ISO 3262-14:2023) specifies requirements and test methods for cristobalite used as an extender (filler) in pigments and related raw materials. Adopted by CEN as a European Standard, it updates and supersedes the 2000 edition and defines compositional limits, test procedures, sampling and reporting requirements to ensure consistent quality and conformity for cristobalite products.
Key topics and technical requirements
- Definition: Cristobalite is identified as a low‑temperature form of crystalline silicon dioxide (SiO2) with a theoretical density of 2.35 g/cm3.
- Essential requirements (Table 1):
- Cristobalite content: minimum 60% by mass, determined by X‑ray diffraction or another method agreed between parties.
- Silica (SiO2) content: minimum 98% by mass (detailed test in Clause 6).
- Matter volatile at 105 °C: max 0.2% (ISO 787‑2).
- Loss on ignition: typically max 0.2% (higher limit 0.5% may apply if surface treatment affects results).
- Matter soluble in water: max 0.2% (ISO 787‑3).
- pH of aqueous suspension: 6–9 (up to 6–10 if surface treated) (ISO 787‑9).
- Conditional requirements (Table 2): particle size distribution (instrumental methods, e.g. ISO 8130‑13 laser diffraction), residue on 45 µm sieve, colour/lightness, resistivity of aqueous extract (ISO 787‑14), oil absorption (ISO 787‑5).
- Silica determination (Clause 6): prescribed analytical procedure using sulfuric and hydrofluoric acids with ignition steps (muffle furnace) and mass-based calculation of SiO2 content.
- Sampling and reporting: sampling per ISO 15528; test reports must identify product details, reference ISO 3262‑14:2023, test results and methods, deviations, anomalies and test date.
Practical applications and users
- Who uses this standard:
- Manufacturers and suppliers of cristobalite extenders.
- Quality control and analytical laboratories testing filler compliance.
- Paints, coatings, ceramics and polymer formulators specifying filler properties.
- Procurement and regulatory teams requiring standardized product specifications.
- Why it matters:
- Ensures consistent product composition (SiO2 and cristobalite content) and physical properties (particle size, pH, oil absorption).
- Provides validated, repeatable test methods for acceptance testing, supplier qualification and formulation compatibility.
Related standards
Keywords: EN ISO 3262-14:2023, ISO 3262-14:2023, cristobalite, extenders, specifications and methods of test, silica content, X-ray diffraction, particle size distribution, ISO 8130-13, ISO 787.
