Overview
ISO 12677:2011 specifies the chemical analysis of refractory and technical ceramic raw materials, intermediates and products using X‑ray fluorescence (XRF) by the fused cast‑bead method. The standard defines the procedure for converting powdered oxide materials into homogeneous glass beads for XRF measurement, calibration and result correction. It applies to a wide range of oxide refractories (e.g., high‑alumina, alumino‑silicate, silica, zircon, magnesia, dolomite, lime, chromites) but is not applicable to non‑oxide materials (silicon carbides, nitrides) unless pretreated by appropriate ignition/fusion methods.
Key topics and technical requirements
- Principle: Grind sample → fuse with suitable flux → cast a glass bead → measure fluorescent X‑rays → calculate composition from calibrations and inter‑element corrections.
- Sample preparation: Preferred grinding with tungsten‑carbide media; maximum particle size 100 µm; corrections for tungsten‑carbide contamination are specified (Annex B).
- Flux and fusion: Choice of flux and flux:sample ratio detailed; fusion temperatures typically use furnaces in the range 1 050 °C to 1 250 °C; use non‑wetting platinum‑alloy vessels (Pt/Au 95/5 recommended).
- Apparatus: Platinum crucibles/casting moulds, electric or induction furnaces, balances (±0.1 mg), mechanical mixers; automatic fusion equipment and rapid cooling (air jet or water‑cooled plate) are described.
- Calibration and standards: Calibrations may be made with pure reagents and/or series reference materials (SeRMs); validation by certified reference materials (CRMs) is required. Annexes cover calibration ranges, SeRMs, CRMs and theoretical calculations.
- Corrections & software: Procedures for line‑overlap, background and drift corrections, inter‑element compensation and software requirements are specified.
- Quality & performance: Repeatability, reproducibility tests, limits of detection (Annex A) and accuracy assessment using CRMs.
Practical applications and users
ISO 12677:2011 is used for reliable chemical composition analysis of refractories and technical ceramics in:
- Quality control laboratories in refractory and ceramic manufacturing
- Materials testing and R&D for kiln linings, crucibles, high‑temperature components
- Incoming materials inspection (raw minerals, fluxes)
- Laboratories performing XRF method development and accreditation
Users include analytical chemists, laboratory managers, process engineers and quality assurance personnel requiring standardized XRF fused bead procedures and traceable results.
Related standards
- ISO 26845 - sampling and wet chemical/ICP/AAS general requirements for refractories
- ISO Guide 35 - reference materials and certification principles
- ISO 21068 (parts 1–3) - preparation of reduced materials (e.g., silicon carbide) prior to XRF bead analysis
This standard ensures consistent fused cast‑bead XRF analysis workflows, clear calibration/validation paths and robust quality control for oxide refractory materials.
Open preview (PDF)Chemical analysis of refractory products by X-ray fluorescence (XRF) — Fused cast-bead method
