ISO 3262-11:2024

Overview

ISO 3262-11:2024 - Extenders: Part 11 - Natural talc, in lamellar form, containing carbonates specifies composition limits and test methods for naturally occurring lamellar talc products associated with carbonates (for example dolomite and magnesite). This second edition updates the 2000 version, clarifies mineralogical grades (A and B), adds quartz and asbestos determinations, and aligns particle size testing with ISO 8130-13 (laser diffraction).

Key topics and technical requirements

• Mineralogical grades: Grade A and Grade B are defined by talc/carbonate proportions and illustrated in a ternary diagram.
• Talc content:
  • Grade A: 90–70% (mass)
  • Grade B: 70–50% (mass)
• Carbonate content:
  • Grade A: 10–30%
  • Grade B: 10–50%
• Total talc/chlorite content: maximum 90% (mass).
• Loss on ignition (LOI):
  • Grade A: 9.5–19.0%
  • Grade B: 11.0–28.6%
• Matter volatile at 105 °C: max 0.5% (ISO 787-2).
• Matter soluble in water: max 0.2% (ISO 787-3).
• pH (aqueous suspension): 8–10 (ISO 787-9).
• Quartz content: max 0.5% (X-ray diffraction).
• Asbestos detection: combination of XRD and SEM/EDX or TEM is required. Typical detection limits: XRD ~0.1%, SEM/EDX or TEM below 0.01%; both morphology and mineral presence must be assessed (ISO 14966).
• Conditional tests (to be agreed between parties): residue on 45 µm sieve (ISO 787-7/18), particle size distribution (ISO 8130-13), matter soluble in HCl, color/lightness, resistivity of aqueous extract (ISO 787-14).
• Test reporting: reports must identify the product, reference ISO 3262-11:2024, give methods and results, note compliance or deviations, record anomalies and test date.

Applications and who uses this standard

ISO 3262-11:2024 is used where natural talc extenders/fillers are specified and controlled, including:

• Paints and coatings manufacturers (fillers to adjust rheology, opacity)
• Plastics, rubber and adhesives producers (extender/filler performance)
• Paper and ceramics industries (functional filler properties)
• Raw material suppliers and distributors (product specifications and claims)
• Quality control and analytical laboratories (routine testing and acceptance)
• Regulatory bodies and procurement specialists needing documented safety checks (notably asbestos and quartz limits)

Implementing this standard supports material selection, supplier agreements, product safety (asbestos/quartz control), and consistent quality for industrial uses of lamellar natural talc containing carbonates.

Related standards

• ISO 3262-1 (general test methods for extenders)
• ISO 3262-2:2023 (baryte reference for HCl solubility clause)
• ISO 8130-13 (particle size by laser diffraction)
• ISO 787 series (general test methods)
• ISO 14966 (inorganic fibrous particle identification)
• ISO 18451-1 (terminology)