Overview
EN 26352:1991 (identical with ISO 6352:1985) specifies a standardized gravimetric method using dimethylglyoxime for the determination of nickel content in ferronickel. The procedure applies to nickel concentrations in the range 15–60 % (m/m) and defines principle, reagents, apparatus, sample preparation, analytical procedure, expression of results and reporting. Two annexes extend the method: Annex A covers atomic absorption spectrometry (AAS) for nickel in combined filtrates; Annex B provides a statistical report from interlaboratory tests.
Key topics and technical requirements
- Scope and range: Designed for ferronickel samples with 15–60 % nickel (m/m).
- Analytical principle:
- Dissolution of test portion in nitric (and where needed, HF/HClO4) acids.
- Removal of silica by perchloric acid and filtration.
- Precipitation of nickel as the nickel–dimethylglyoxime complex from a tartro‑ammoniacal medium, two successive precipitations and gravimetric weighing after drying at 150 °C.
- Determination of residual nickel in filtrates by atomic absorption spectrometry (Annex A) for correction.
- Reagents and apparatus: Lists required reagents (e.g., dimethylglyoxime solution, tartaric acid, HF, HClO4) and calibrated glassware per ISO specifications. Safety warnings highlight hazards of hydrofluoric and perchloric acid and recommend appropriate fume-cupboard use.
- Precision and validation: Method performance was assessed via an interlaboratory programme (7 countries, 20 laboratories, 39 analysts, 8 commercial ferronickel samples). Annex B documents repeatability and reproducibility data and statistical treatment following ISO principles.
- Reporting: Specifies calculation formulae, correction for nickel remaining in filtrates, and required information in the test report.
Practical applications
- Quality control and incoming/outgoing inspection of ferronickel in ferroalloy and stainless-steel production.
- Metallurgical laboratories needing a traceable, standardized method for nickel determination.
- Situations where gravimetric confirmation is required alongside instrumental methods (AAS) for accuracy and verification.
- Method validation, proficiency testing, and interlaboratory comparisons within alloy analysis programs.
Who should use this standard
- Industrial QC/analytical chemists in ferroalloy and steel industries
- Materials testing and metallurgical laboratories
- Standards organizations and accreditation bodies performing method verification or proficiency studies
Related standards
Keywords: EN 26352:1991, ISO 6352:1985, ferronickel, nickel determination, dimethylglyoxime gravimetric method, atomic absorption, gravimetric analysis, repeatability, reproducibility, ferroalloys.