Overview
ISO 13311:1997 specifies a flame atomic absorption spectrometric (FAAS) method for the determination of lead (Pb) content in iron ores. The procedure applies to natural iron ores, concentrates and agglomerates (including sinter) with lead contents from 0.001% to 0.5% (m/m). The standard describes sample preparation, reagent and apparatus requirements, calibration, measurement and reporting of results.
Key topics and technical requirements
- Analytical principle: decomposition of the ore with hydrochloric and hydrofluoric acids, oxidation with nitric acid, removal of silica, fusion of residue with sodium carbonate, extraction of iron with 4‑methyl‑2‑pentanone (MIBK), recovery of lead and measurement by FAAS.
- Instrumentation: atomic absorption spectrometer with air–acetylene burner; wavelength for Pb set at 283.3 nm. The instrument must meet minimum sensitivity, linearity and stability criteria before use.
- Reagents and standards: use analytical‑grade acids (HCl, HNO3, HF), MIBK, anhydrous sodium carbonate and prepared lead stock/working standards (stock = 1 000 µg/ml; serial working standards described in the standard).
- Sampling and sample prep: laboratory sample milled to minus 100 µm (minus 160 µm for ores with significant combined water or oxidizable compounds) and predried at 105 °C ± 2 °C per referenced ISO sampling/preparation standards.
- Procedure controls: perform analyses in duplicate, include a blank and a certified reference material (CRM) in each run, and follow specified dilution and calibration protocols to convert absorbance to µg Pb/ml and to % Pb.
- Precision and quality: the standard provides methods to evaluate repeatability and between‑laboratory reproducibility (expressed by regression/precision relationships) and requires checking trueness with a CRM.
- Safety: warns about hazardous reagents (HF, acids, flammable solvents) and flame operation; users must apply appropriate safety measures.
Applications and users
ISO 13311:1997 is used for:
- Quality control and assay of iron ore feedstock, concentrates and sinter products.
- Metallurgical and mining laboratory testing to monitor Pb contamination and meet product specifications.
- Regulatory and environmental testing where lead content in ore materials is required.
Typical users: mineral processing laboratories, metallurgical QA/QC teams, third‑party testing labs, instrument manufacturers, and producers of certified reference materials.
Related standards
Normative references and related ISO documents cited include:
Keywords: ISO 13311:1997, iron ores, lead determination, flame atomic absorption spectrometry, FAAS, sample preparation, MIBK, hydrofluoric acid, sodium carbonate, certified reference material.