ISO 3262-2:2023

Overview

ISO 3262-2:2023 - Extenders - Part 2: Baryte (natural barium sulfate) - specifies composition requirements and corresponding methods of test for natural baryte (BaSO4). This second edition updates the first (1998), introduces an X‑ray fluorescence (XRF) option for BaSO4 determination, and aligns test methods and sampling with current ISO practice. The standard is intended for manufacturers, suppliers and quality laboratories working with extenders and fillers used in pigments, paints and related industries.

Key topics and technical requirements

• BaSO4 content (barium sulfate): Minimum mass fraction requirements for Grade A (≥ 90%) and Grade B (≥ 80%). Both gravimetric and XRF methods are permitted for determination.
• Physical and chemical limits:
  • Residue on 45 µm sieve: Grade A max 0.5% (Grade B by agreement).
  • Matter volatile at 105 °C: max 0.5% (ISO 787-2).
  • Loss on ignition: Grade A max 1% (methods referenced in ISO 3262-1).
  • pH of aqueous suspension: 6 to 10 (ISO 787-9).
• Conditional requirements: Particle size distribution, colour, lightness, matter soluble in water, resistivity of aqueous extract, and matter soluble in hydrochloric acid can be specified by agreement between parties.
• Test methods referenced: Key analytical standards used in ISO 3262-2:2023 include ISO 787 series (general test methods for pigments and extenders), ISO 12677 (XRF fused bead), ISO 15528 (sampling), ISO 3696 (water for analysis), and ISO 4793 (sintered filters).
• Analytical approaches: Clause 6 details a gravimetric fusion/filtration procedure for BaSO4; Clause 7 provides an XRF alternative. Sampling is specified per ISO 15528.

Applications and who uses this standard

ISO 3262-2:2023 is used by:

• Manufacturers and suppliers of baryte (barium sulfate) extenders for quality specification and product declarations.
• Quality control and analytical laboratories performing routine BaSO4 determination (gravimetric or XRF), sieve residue, moisture and pH tests.
• Downstream users in paints, coatings, inks, plastics, rubber, paper and ceramics who require consistent filler properties for formulation performance and regulatory compliance.
• Procurement teams and conformity assessors who need standardized acceptance criteria for extenders.

Related standards

• ISO 3262-1 (General test methods for extenders)
• ISO 787 series (Parts 2, 3, 7, 9, 14) - general methods for pigments and extenders
• ISO 15528 (Sampling)
• ISO 12677 (XRF fused-bead method)
• ISO 3696 (Laboratory water)
• ISO 4793 (Sintered filters)
• ISO 18451-1 (Terminology)

Keywords: ISO 3262-2:2023, baryte, barium sulfate, BaSO4, extenders, specifications, methods of test, XRF, gravimetric analysis, pigments, coatings, sampling.