Overview
ISO/TS 9516-4:2021 - “Iron ores - Determination of various elements by X‑ray fluorescence spectrometry - Part 4: Performance‑based method using fusion preparation method” - defines a performance‑based XRF procedure for chemical analysis of natural and processed iron ores. The specification covers both wavelength‑dispersive (WDXRF) and energy‑dispersive (EDXRF) X‑ray fluorescence instruments using fused‑bead sample preparation. It is applicable to all elements of interest (elemental range B to U) provided adequate calibrations are established.
Key topics and technical requirements
- Performance‑based approach: Specifies required analytical performance and validation criteria rather than prescribing every operational detail, enabling flexibility for different instruments and laboratories.
- Fusion (fused‑bead) sample preparation: Describes preparation of borate glass beads to eliminate particle‑size effects and produce homogeneous specimens for XRF analysis.
- Reagents and flux: Requires analytical‑grade reagents; recommends high‑purity lithium/sodium borate fluxes. The document notes pre‑treatment of oxides (e.g., heating to 1 000 °C) and gives typical sample:flux ratios (commonly 1:10).
- Sampling and sample preparation: Details laboratory sample definitions, preparation of predried test samples, and handling of ores with combined water or oxidizable compounds.
- Instrument measurements: Guidance on choice of analytical lines, voltage/current settings, measuring times, and background measurements for both WDXRF and EDXRF.
- Calibration and validation: Procedures for preparing fusion beads for calibration, use of certified reference materials (CRMs) and reference materials (RMs), validation of trueness, and calibration maintenance (monitor discs, duplicate checks).
- Quality control and reporting: Requirements for ongoing QC measurements, calculation of results, number of significant figures/decimals, and content of the test report.
Applications and users
ISO/TS 9516-4:2021 is intended for:
- Mineral and iron ore laboratories performing routine and forensic chemical analysis.
- Mining and beneficiation operations conducting quality control of feedstocks and products.
- Producers, traders and consumers of iron ore who require consistent elemental assays.
- Accredited testing laboratories and instrument manufacturers developing calibrations and validation protocols for XRF fused‑bead methods.
Practical benefits include faster multi‑element screening, reduced sample heterogeneity versus pressed powders, and compatibility with laboratory QA/QC programs when CRMs and validated calibrations are used.
Related standards
- ISO 9516‑1 (preparative procedures and oxidation state guidance)
- ISO 2596 (hygroscopic moisture)
- ISO 3082 (sampling and sample preparation procedures)
- ISO 7764 (preparation of predried test samples)
- ISO Guide 31 and ISO Guide 35 (reference materials guidance)
Keywords: ISO/TS 9516-4:2021, iron ores, XRF, fused bead, fusion preparation, wavelength dispersive XRF, energy dispersive XRF, calibration, certified reference materials, analytical method.