Overview
ISO 13312:2017 - "Iron ores - Determination of potassium - Flame atomic absorption spectrometric method" specifies a validated laboratory procedure for determining the mass fraction of potassium in iron ores, concentrates and agglomerates (including sinter). The method uses flame atomic absorption spectrometry (FAAS) after acid decomposition and is applicable to potassium mass fractions from 0.0025 % to 0.52 %. The standard includes sample preparation, reagents, apparatus, calibration and quality-acceptance procedures.
Keywords: ISO 13312:2017, potassium determination, iron ores, FAAS, flame atomic absorption spectrometry, sample preparation, metallurgical QC.
Key topics and technical requirements
- Scope and applicability
- Potassium in natural iron ores, concentrates and agglomerates; concentration range 0.0025–0.52 %.
- Principle
- Decompose a predried test portion with hydrochloric and hydrofluoric acids, evaporate to dryness, dissolve and aspirate into an air/acetylene flame for absorbance measurement against calibration solutions.
- Sampling and test portion
- Laboratory sample particle size: typically −100 µm (−160 µm for ores with significant combined water or oxidizable compounds).
- Typical test portion mass: 0.2 g to 0.5 g (weighed to 0.0002 g).
- Reagents
- Use analytical-grade reagents and Grade 2 water (ISO 3696). Required reagents include hydrochloric acid, hydrofluoric acid, an iron-based background solution and a 20 µg K/ml standard solution.
- Apparatus and contamination control
- Prefer PTFE/plastic labware (PTFE beakers, coated stirrers, digestion bombs, plastic volumetric flasks). Avoid glassware to reduce contamination risks.
- Cleaning and blank checks are specified; blank test and check test procedures must be performed.
- Instrument criteria
- FAAS sensitivity and stability requirements are defined (e.g., absorbance of most concentrated calibration ≥ 0.25; stability and linearity criteria).
- Guideline instrument settings are provided (e.g., K lamp, wavelength 766.5 nm; air/acetylene flows listed as examples).
- Quality and reporting
- Procedures for duplicate determinations, calibration, repeatability, inter-laboratory precision, trueness checks and acceptance of analytical values (Annex A, B, C) are included.
Applications and who uses it
- Used by:
- Mining and iron-ore laboratories, metallurgical QC teams, contract analytical labs and research institutions.
- Practical applications:
- Routine quality control of ore and concentrate shipments
- Product specification compliance (sinter, concentrates)
- Process monitoring and elemental impurity assessment
- Research on ore chemistry and beneficiation outcomes
Related standards
- ISO 3082 - Sampling and sample preparation procedures
- ISO 7764 - Preparation of predried test samples
- ISO 2596 - Determination of hygroscopic moisture
- ISO 3696 - Water for analytical laboratory use
- ISO 648 / ISO 1042 - Laboratory glassware (pipettes, volumetric flasks)
- ISO 11323 - Vocabulary for iron ore and DRI
Safety note: The procedure uses hazardous acids (HF, HCl) and hot flames - follow laboratory safety and local regulations.