Overview
ISO 3262-10:2024 specifies requirements and corresponding methods of test for products made from naturally occurring talc/chlorite in lamellar form. Published as part of the ISO 3262 series on extenders, this second edition updates the mineralogical grading, adds quartz and asbestos determinations to essential requirements, and aligns particle-size testing with ISO 8130-13.
This standard is intended for manufacturers, quality laboratories and specifiers who need a consistent framework to classify, test and document lamellar talc/chlorite extenders.
Key Topics
- Scope and definitions: Clarifies the term "natural talc/chlorite" as the natural association of talc and chlorite in lamellar morphology, with terminology aligned to ISO 18451-1.
- Mineralogical grades: Products are allocated to grades A, B, C and D based on talc/chlorite proportions (see Table 1 and the ternary diagram in the standard).
- Essential requirements: Include talc/chlorite content ranges, loss on ignition, matter volatile at 105 °C, matter soluble in water, pH (where specified) and limits for quartz and asbestos.
- Test methods: Referenced normative methods include X-ray diffraction (XRD), SEM/EDX or TEM for fibre/asbestos detection, ISO 8130-13 for particle-size distribution, and several ISO 787 series methods for volatility, solubility, sieving and resistivity.
- Asbestos detection: The standard requires a combination of XRD and microscopy (SEM/EDX or TEM) because XRD alone cannot reliably determine asbestos morphology or meet low detection limits.
- Conditional requirements: Include residue on 45 µm sieve, particle-size distribution, hydrochloric acid solubility and colour/lightness or other properties to be agreed between parties.
Applications
ISO 3262-10:2024 provides practical value by enabling:
- Consistent quality control and batch acceptance for talc/chlorite extenders.
- Clear grade specification to match extender properties with end-use requirements.
- Reliable safety screening for quartz and asbestos to support regulatory compliance and workplace safety.
Typical industrial uses of lamellar talc/chlorite extenders include incorporation in coatings, paints, plastics, rubber compounds and other formulated products where filler performance and mineralogy affect processing and product properties.
Related Standards
- ISO 3262-1 - Introduction and general test methods for extenders
- ISO 3262-2:2023 - Baryte (natural barium sulfate) specifications
- ISO 8130-13 - Particle size analysis by laser diffraction (coating powders)
- ISO 787 series - General methods for pigments and extenders (volatility, solubility, sieving, pH, resistivity)
- ISO 14966 - SEM method for inorganic fibrous particles
Test Report Requirements
The standard specifies minimum information for test reports: product identification, reference to ISO 3262-10:2024, test results and methods used, conformity statement against specification limits, any deviations or anomalies and the test date. This ensures traceable, auditable quality documentation for suppliers and purchasers.