Overview
ISO 15247:2015 specifies an analytical procedure for the determination of silver content in zinc sulfide concentrates by acid dissolution followed by flame atomic absorption spectrometry (FAAS). The method applies to zinc sulfide concentrates (zinc blende and related materials) containing up to 60 % (m/m) zinc and to silver concentrations in the range 10 g/t to 500 g/t. It covers sample preparation, reagent and apparatus requirements, calibration, measurement conditions and expression of results.
Key topics and technical requirements
- Sample preparation
- Test-sample preparation in accordance with ISO 9599 or use of predried test portions (Annex A).
- Representative test portions (≈1 g) and parallel determination of hygroscopic moisture.
- Acid decomposition
- Decomposition of sample using nitric acid and hydrochloric acid, with prescribed evaporation and re-dissolution steps.
- Emphasis on glassware cleaning (ammonia rinse) to avoid silver contamination.
- Reagents and standards
- Use of analytical-grade reagents and Grade 2 water (ISO 3696).
- Preparation of silver primary and working standard solutions and calibration solutions in hydrochloric acid matrix.
- Instrumental measurement (FAAS)
- Measurement by flame atomic absorption spectrometry at 328.1 nm (air–acetylene flame recommended).
- Example instrument settings provided (lamp current 5 mA, integration and aspiration guidance); calibration with multiple standards and replicate readings.
- Quality control and reporting
- Mandatory blank tests, duplicate determinations (minimum duplicate), and calibration checks.
- Expression of results in g/t with correction for hygroscopic moisture.
- Precision and repeatability expressed through formal statistical equations and limits (see Clause 9 and Annex C).
- Safety & handling
- Controlled heating to avoid splattering; standard laboratory safety for strong acids.
Practical applications and users
ISO 15247:2015 is intended for:
- Mining and mineral processing laboratories performing assay and grade control of zinc sulfide concentrates.
- Metallurgical and analytical service laboratories conducting silver quantification for commercial settlement, process monitoring and certification.
- Quality assurance teams and regulators requiring a standardized FAAS-based method for consistent, traceable silver determinations.
Benefits:
- Enables reproducible, comparable results across laboratories.
- Supports commercial transactions (concentrate valuation), process optimization and compliance testing.
Related standards
Keywords: ISO 15247:2015, zinc sulfide concentrates, silver determination, acid dissolution, flame atomic absorption spectrometry, FAAS, assay method, concentrate analysis, analytical standard.
Open preview (PDF)Zinc sulfide concentrates — Determination of silver content — Acid dissolution and flame atomic absorption spectrometric method