ISO 3262-17:2024

Overview

ISO 3262-17:2024 - "Extenders - Specifications and methods of test - Part 17: Precipitated calcium silicate" specifies requirements and corresponding test methods for precipitated calcium silicate used as an extender/filler. The standard defines the material (an amorphous silicate precipitated by reaction of sodium silicate with a mineral acid and/or a calcium salt) and describes mandatory and conditional characteristics, sampling rules and laboratory test procedures for quality control.

Key topics and technical requirements

• Essential characteristics and limits (Table 1):
  • Silica content: minimum 75% (determination in Clause 6 or Clause 7)
  • Oxide content: Na2O (1–5% mass fraction) and CaO (2–24% mass fraction) by spectrometry
  • Residue on 45 µm sieve: max 2% mass fraction
  • Matter volatile at 105 °C: max 10% (ISO 787-2)
  • Loss on ignition: 3–10% (ISO 3262-1)
  • Oil absorption: minimum 80 g/100 g (ISO 787-5 or ISO 19246)
  • pH of aqueous suspension: 8–12 (ISO 787-9)
• Conditional characteristics (Table 2):
  • Particle size distribution (laser diffraction, ISO 13320)
  • Lightness (tristimulus value Y - DIN 53163)
  • Specific surface area (ISO 5794-1:2022, Annex E)
• Analytical methods described:
  • Silica determination by acid digestion, dehydration, ignition, HF treatment and mass-loss measurement (Clause 6)
  • Composition by spectrometry (Ca, Na, Si) with calibration and oxide conversion (Clause 7)
  • Residue on sieve testing procedures (Clause 8)
• Sampling and testing protocol:
  • Representative sampling per ISO 15528
  • Duplicate determinations and stated precision requirements
  • Specified reagents and apparatus (e.g., HCl, HF, muffle furnace, platinum crucible)

Applications and who uses this standard

• Manufacturers of extenders and fillers: to specify product acceptance criteria and to demonstrate compliance.
• Quality control laboratories: for routine testing of precipitated calcium silicate batches.
• Paints, coatings and rubber compound formulators: to select extenders that meet performance and compatibility requirements (oil absorption, pH, particle size).
• Purchasing/specification engineers: to include verifiable test requirements in procurement and technical data sheets.
• Standards bodies and testing labs: for harmonized test methods and inter-laboratory consistency.

Related standards

• ISO 3262-1 (general test methods for extenders)
• ISO 787 series (volatile matter, oil absorption, pH)
• ISO 13320 (particle size - laser diffraction)
• ISO 15528 (sampling)
• ISO 5794-1:2022 (specific surface area of precipitated silica)
• ISO 19246 and DIN 53163 (alternative methods for oil absorption and lightness)

Keywords: ISO 3262-17:2024, precipitated calcium silicate, extenders, specifications, methods of test, silica content, oxide content, oil absorption, particle size, testing procedures.