Overview
ISO 6352:1985 specifies a gravimetric dimethylglyoxime (DMG) method for determining nickel content in ferronickel. The method applies to nickel contents in the range 15–60 % (m/m) and sets out the principle, reagents, apparatus, sampling, detailed procedure, expression of results and the test report. Two annexes supplement the method: Annex A describes atomic absorption spectrometry (AAS) for determining residual nickel in combined filtrates, and Annex B gives a statistical report of interlaboratory tests.
Key topics and requirements
- Scope and principle: Dissolve a weighed test portion, remove silica (perchloric acid dehydration), precipitate nickel as the dimethylglyoxime complex from a tartrato‑ammoniacal medium, collect, dry and weigh the precipitate; correct for residual nickel in filtrates by AAS.
- Reagents and apparatus: Specifies analytical‑grade reagents (nitric, hydrochloric, perchloric, hydrofluoric acids; tartaric acid; ammonium hydroxide; DMG in ethanol) and calibrated glassware (pipettes, volumetric flasks, fritted glass crucible, PTFE beaker for high‑silicon samples).
- Safety warnings: Emphasizes hazards associated with perchloric acid (oxidizing, explosive mixtures with organics) and hydrofluoric acid (severe skin burns). Perchloric work must be performed in suitable fume cupboards.
- Procedure details: Test‑portion mass, dissolution steps, silica filtration, two successive DMG precipitations, drying at 150 °C, and combining filtrates for AAS analysis per Annex A.
- Quality and precision: Provides calculation method and precision data from interlaboratory studies. Representative precision figures: repeatability r ≈ 0.13% (15–30% Ni) and 0.19% (31–45% Ni); reproducibility R ≈ 0.24% and 0.35% respectively. Combined filtrates should not exceed about 0.2% Ni in the original sample.
Applications and users
- Routine chemical analysis and quality control in ferroalloy plants and metallurgical laboratories.
- Incoming inspection and certification for buyers, sellers and customs testing of ferronickel consignments.
- Laboratories performing comparative testing or method validation where a standardized gravimetric reference method is required.
- Useful for regulatory compliance, specification verification and research into nickel recovery or alloy composition.
Related standards
Keywords: ISO 6352, ferronickel, nickel determination, dimethylglyoxime, gravimetric method, atomic absorption, ferroalloys, laboratory procedure, nickel analysis.