Overview
ISO 11533:2009 specifies a flame atomic absorption spectrometric (AAS) method for determining the mass fraction of cobalt in iron ores. The method covers natural iron ores, concentrates and agglomerates (including sinter) and is applicable to cobalt levels from 0.0007 % to 0.06 % (mass fraction). The standard describes sample preparation, reagents, apparatus, analytical procedure, calibration and reporting requirements.
Key topics and technical requirements
- Scope and detection range: Designed for low-level cobalt determination in iron-bearing materials (0.0007–0.06 %).
- Sampling and sample prep: Uses a laboratory sample of minus 100 µm (or minus 160 µm for ores with significant combined water/oxidizable compounds) and a predried test sample per ISO 7764.
- Test portion and replicates: Typical test portion ≈ 2 g (weighed to 0.0002 g) and analyses carried out at least in duplicate; inclusion of a blank and a certified reference material is required for each run.
- Chemical decomposition: Multi-acid digestion sequence using hydrochloric, nitric, sulfuric and hydrofluoric acids; residue ignition, HF treatment, fusion with sodium carbonate and recombination of filtrates.
- Interference control: Iron is removed by extraction with isobutyl acetate before AAS measurement to minimize matrix effects.
- Instrumentation and performance criteria: Atomic absorption spectrometer with air/acetylene burner. Performance checks include minimum sensitivity and linearity at 240.7 nm and 252.2 nm, stability criteria for repetitive measurements, and recommended instrument parameters.
- Calibration and QA: Use of cobalt stock and working standards, calibration graphs, blank tests and certified reference materials. Annexes provide flowsheets, repeatability/permissible tolerances and inter-laboratory precision data.
- Safety: Method involves hazardous acids (HF, HNO3, HCl, H2SO4) and high-temperature fusion-appropriate laboratory safety and regulatory compliance are mandatory.
Applications and users
ISO 11533:2009 is intended for:
- Mineral assay laboratories and process control labs in mining operations
- Quality control for iron ore concentrates, sinter and agglomerates
- Metallurgical laboratories monitoring trace cobalt content prior to smelting or alloy production
- Regulatory and commercial testing where standardized, reproducible cobalt determination is required
Using this standard ensures traceable, comparable cobalt results across laboratories involved in ore characterization, product specification and trade.
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, volumetric flasks)
Keywords: ISO 11533:2009, cobalt determination, iron ores, flame atomic absorption spectrometry, AAS, sample preparation, analytical method, trace cobalt, isobutyl acetate extraction.
Open preview (PDF)Iron ores — Determination of cobalt — Flame atomic absorption spectrometric method
