Overview
ISO 11535:2006 specifies an analytical procedure for the determination of aluminium, calcium, phosphorus, magnesium, manganese, silicon and titanium in iron ores using inductively coupled plasma atomic emission spectrometry (ICP‑AES). The method covers natural iron ores, concentrates and agglomerates (including sinter) and defines sample preparation, fusion/dissolution, calibration and measurement requirements to produce traceable, comparable results.
Key mass‑fraction ranges covered (Table 1):
- Al: 0.07–3.30 %
- Ca: 0.012–6.80 %
- Mg: 0.008–1.90 %
- Mn: 0.012–1.70 %
- P: 0.011–1.60 %
- Si: 0.44–9.40 %
- Ti: 0.018–0.17 %
Key topics and technical requirements
- Analytical principle: Fusion of a ~0.5 g test portion with a sodium carbonate / sodium tetraborate flux, dissolution in hydrochloric acid, dilution and measurement by ICP‑AES using calibration graphs.
- Reagents & solutions: High‑purity Fe2O3, Na2CO3, Na2B4O7, HCl/HNO3 and prepared 1 000 µg/ml stock solutions (Al, Ca, Mg, Mn, P, Si, Ti).
- Apparatus: Precision balance, platinum crucibles, muffle furnace (≥1 020 °C), hotplate/stirrer, and a performance‑qualified ICP spectrometer.
- Sampling & sample prep: Use laboratory samples prepared per ISO 3082; particle size typically minus 100 µm (minus 160 µm where combined water/oxidizable compounds are significant). Predrying and representative test portions are specified (see ISO 7764).
- Quality control: At least duplicate independent determinations, blank tests, certified reference material checks, instrument performance tests, calibration with a minimum of 10 solutions and checks for spectral interference, background and drift correction.
- Data treatment: Calibration graphs, spectral‑interference corrections, drift standardization, repeatability/permissible tolerances, oxide factors and acceptance flowsheets are included.
Applications and users
ISO 11535:2006 is intended for:
- Mining and beneficiation laboratories performing routine chemical assays of iron ore and concentrates.
- Metallurgical and steel producers monitoring feedstock composition (Si, P, Mn, Al, Ti, Ca, Mg).
- Independent assay houses and port laboratories validating consignments for trade and quality control.
- Instrument manufacturers and method developers seeking benchmark performance criteria for ICP‑AES in ore matrices.
Benefits include standardized sample handling, consistent calibration practice, and improved comparability of elemental data across labs.
Related standards
- ISO 3082 - Sampling and sample preparation procedures for iron ores
- ISO 7764 - Preparation of predried test samples for chemical analysis
- ISO 3696 - Water for analytical laboratory use
- ISO 648 / ISO 1042 - Laboratory glassware (pipettes and volumetric flasks)
Keywords: ISO 11535:2006, iron ores analysis, ICP‑AES, inductively coupled plasma atomic emission spectrometry, aluminium, calcium, phosphorus, magnesium, manganese, silicon, titanium.