Overview
ISO 20565-3:2008 specifies laboratory procedures using flame atomic absorption spectrometry (FAAS) and inductively coupled plasma atomic emission spectrometry (ICP‑AES / ICP‑AES) for the chemical analysis of chrome‑bearing refractory products and chrome‑bearing raw materials. The standard provides an alternative to X‑ray fluorescence (XRF, ISO 12677) and integrates with sample dissolution and preparation methods given in ISO 20565‑1.
Key measured oxides include SiO2, Al2O3, Fe2O3, TiO2, MnO, CaO, MgO, Na2O, K2O, Cr2O3, ZrO2 and P2O5. Tableed application ranges in the standard (examples): SiO2 0.5–10 %, Al2O3 2–30 %, Cr2O3 2–60 %. ICP‑AES also defines specific working ranges for many components (e.g., SiO2 0.1–10 %, Al2O3 0.05–10 %, Cr2O3 0.01–10 %).
Key topics and requirements
- Analytical methods: Procedures for FAAS and ICP‑AES determinations as alternatives to XRF.
- Sample preparation: Uses the dissolution and stock solution protocols referenced to ISO 20565‑1 (apparatus, reagents, fusion/dissolution and gravimetric silica determination).
- Calibration and matrix matching: Preparation of mixed standard solutions and matrix solutions (series calibration solutions) to match sample composition and reduce matrix interferences.
- Internal standards: Use of internal standard elements (example: Sc and Y) with ICP‑AES to improve accuracy and correct for signal drift.
- Blank tests and calculation formulas: Procedures include blank determinations and explicit calculation equations for converting emission/absorption signals into mass fractions (% by mass).
- Element wavelengths and detection: Example ICP wavelengths are provided (e.g., Si 251.611 nm, Al 396.152 nm, Cr 267.716 nm, Na 588.995 nm, K 766.491 nm) to guide instrumental setup.
- Quality considerations: Emphasis on checking line interferences, range limits for reliable determination (see Table ranges), and performing fresh calibration for each set of determinations.
Practical applications
- Routine quality control and compositional analysis in refractory production and raw‑material supply chains.
- Laboratory certification and acceptance testing of chrome‑bearing refractories used in steelmaking, foundries and high‑temperature industrial applications.
- Situations where XRF is unsuitable or alternative wet/instrumental methods are required for trace or matrix‑challenging samples.
- Method selection: ICP‑AES is suited for simultaneous multi‑element analysis and higher throughput; FAAS can be used for targeted determinations where appropriate.
Who should use this standard
- Analytical laboratories testing refractories and raw materials.
- QC/production engineers in refractory manufacturers and steel plants.
- Accreditation bodies and laboratory managers implementing standardized test methods.
- Technical personnel deciding between XRF and wet/instrumental alternatives for chrome‑bearing materials.
Related standards
Keywords: ISO 20565‑3:2008, FAAS, ICP‑AES, chrome‑bearing refractory, chemical analysis, refractory raw materials, chromium oxide, XRF alternative.