Overview
ISO 11534:2006 - "Iron ores - Determination of tin - Flame atomic absorption spectrometric method" specifies a validated analytical procedure for measuring tin (Sn) mass fraction in iron ores, concentrates and agglomerates (including sinter). The method applies to tin contents between 0.001 % and 0.015 % and uses flame atomic absorption spectrometry (flame AAS / AAS) after chemical decomposition, fusion and solvent extraction. The standard includes sample preparation, instrumentation requirements, calibration, quality control and precision criteria.
Key topics and technical requirements
- Scope and applicability: Natural iron ores, concentrates and agglomerates; tin range 0.001–0.015 %.
- Sampling and sample prep: Use a laboratory sample of minus 100 µm (or minus 160 µm for ores with significant combined water/oxidizable compounds). Predry samples at 105 °C ± 2 °C (see ISO 7764).
- Decomposition & fusion: Test portion (~2 g) is treated with sulfuric and hydrofluoric acids, heated (muffle furnace 1000–1020 °C), then fused with sodium carbonate / sodium tetraborate flux and dissolved in hydrochloric acid.
- Chemical reduction & extraction: Iron is reduced (ascorbic acid + potassium iodide) and tin is extracted into a TOPO/MIBK organic phase (tri-n-octyl phosphine oxide in methyl isobutyl ketone).
- Flame AAS measurement: Aspirate TOPO/MIBK extract into a dinitrogen oxide/acetylene flame; measure absorbance at 286.3 nm using a tin hollow‑cathode lamp.
- Instrument performance criteria: Minimum sensitivity and linearity requirements for the AAS; stability limits for absorbance (detailed in the standard). Example operational parameters (used as guidelines) include N2O flow ≈ 6.6 L/min and C2H2 ≈ 4.5 L/min.
- Quality control: Run blanks and at least one certified reference material (CRM) in each batch. Perform duplicate independent determinations and follow acceptance/precision procedures (repeatability, between‑laboratory precision) given in the annexes.
- Safety: Handling HF, strong acids and high-temperature fusions requires appropriate laboratory safety controls.
Applications and users
- Who uses it: Analytical laboratories in mining companies, ore processors, independent testing labs, and quality control units that require reliable tin assays in iron ores.
- Practical value: Provides a standardized, reproducible procedure for regulatory compliance, product specification, trade disputes, process control and metallurgical evaluation where low-level tin determination is required.
- Keywords: ISO 11534:2006, tin determination, iron ores, flame AAS, TOPO/MIBK extraction, sample preparation, analytical method.
Related standards
- ISO 3082 - Sampling and sample preparation procedures (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 specifications
This concise summary helps laboratories and procurement teams understand the method, its technical requirements, and where ISO 11534:2006 fits into mineral analysis workflows.