Overview
ISO 19976-2:2019 specifies an acid digestion and ICP‑AES method for the determination of cadmium mass fraction in copper, lead and zinc sulfide concentrates. The method is applicable to:
- Copper and lead sulfide concentrates: 0.01 % to 0.30 % Cd
- Zinc sulfide concentrates: 0.05 % to 1.00 % Cd
The standard defines sample preparation, reagents, apparatus, measurement (ICP‑AES at 226.502 nm) and reporting requirements for reliable cadmium analysis.
Key topics and technical requirements
- Principle: Dissolve test portions by sequential acid digestion (HCl, HNO3, HF and a final perchloric acid stage) and determine cadmium by inductively coupled plasma atomic emission spectrometry (ICP‑AES) with yttrium as an internal standard.
- Reagents: Use analytical‑grade acids (concentrated/dilute HCl, HNO3, HF, HClO4), certified cadmium standard solutions and yttrium internal standard solutions.
- Apparatus: ICP‑AES instrument (emission line 226.502 nm recommended), PTFE or glass‑carbon beakers, Class A volumetric glassware, analytical balance (0.1 mg), Whatman No. 40 or equivalent filter paper.
- Sample & test portion: Laboratory sample preparation per ISO 12743 and moisture equilibration per ISO 9599. Typical test portion ≈ 0.50 g (weighed to 0.1 mg); duplicate determinations are required where possible.
- Procedure controls: Blank tests to check reagent contamination; filtration and washing requirements for lead concentrates; preparation of calibration solutions and cadmium calibration curve using certified standards; use of internal standard for matrix compensation.
- Quality & precision: The standard includes instructions for precision expression, between‑laboratory precision checks and procedures for trueness assessment using reference materials.
Applications and users
ISO 19976-2:2019 is intended for:
- Mining and concentrate assay laboratories performing quality control and elemental assay of sulfide concentrates.
- Smelter laboratories and metallurgical QA teams monitoring feedstock cadmium levels.
- Third‑party and contract analytical labs providing certified assays for trading, compliance or payability calculations.
- Regulatory or environmental labs concerned with cadmium content in ores and concentrates.
Practical benefits include standardized sample digestion, reproducible ICP‑AES measurement, and harmonized reporting that supports commercial, metallurgical and regulatory decision‑making.
Related standards
- ISO 19976 series (other parts)
- ISO 12743 (sampling for metal and moisture)
- ISO 9599 (hygroscopic moisture of test samples)
- ISO 385, 648, 1042, 4787 (laboratory glassware and volumetric methods)
- ISO Guide 35 (reference materials)
- ISO 8466‑2 (calibration strategy)
Note: The method involves hazardous acids and fuming steps - follow appropriate health, safety and laboratory waste protocols.
