Overview - ISO 11459:1997 (Iron ores, Certified reference materials)
ISO 11459:1997 specifies requirements for producing and certifying certified reference materials (CRMs) made from iron ores for use in chemical analysis. Prepared by ISO/TC 102 (Iron ores), this standard defines physical form, homogeneity, particle-size requirements, preparation procedures (pulverization, blending, subdivision) and statistical methods for homogeneity testing and certification. It is intended to be used alongside ISO Guides (30, 31, 33, 35) and accuracy standards (e.g., ISO 5725 series).
Key topics and technical requirements
- Physical form and stability
- CRMs must be supplied as homogeneous powders with minimal volatile content and low oxidizability; mineralogy should support stability during use.
- Homogeneity
- Homogeneity must be demonstrated at three levels: during blending, after subdivision into units, and by interlaboratory control.
- Homogeneity testing must use analytical methods at least as precise as typical user methods and test-portion sizes similar to normal practice.
- Statistical evaluation (e.g., ANOVA) is used; a significance level of α = 0.05 is recommended.
- Particle size
- The standard specifies particle-size limits for CRMs (as given in the standard text) and requires distribution assessment per ISO 4701.
- Preparation
- Pulverization, grinding, sieving and blending must avoid excessive contamination from media abrasion. Sieving may remove hard fractions that cause heterogeneity.
- Certification and characterization
- Primary (certified) and secondary characteristics must be identified.
- Certification should use multiple analytical methods when available, including at least one internationally recognized or reference method (use ISO methods where applicable).
- Certification relies on an interlaboratory test program: minimum of 10 usable laboratory results; for one-unit designs, a minimum of three replicate determinations per laboratory (n = 3).
- Documentation
- Certificates, certification reports and preparation/characterization reports must accompany CRMs, with uncertainty statements and storage/expiration guidance.
Applications and users
ISO 11459 is used by:
- CRM producers and certifying bodies preparing iron ore reference materials
- Analytical laboratories validating methods for iron ore chemical analysis
- Mining and mineral processing companies ensuring measurement traceability
- Standards bodies and proficiency-testing organizers
Practical uses include method validation, quality control of routine analyses, calibration of analytical instrumentation, and assessment of trueness and precision in interlaboratory studies.
Related standards (select)
- ISO Guides 30, 31, 33, 35 (reference materials guidance)
- ISO 5725-2, ISO 5725-4 (accuracy, precision, trueness)
- ISO 4701 (particle-size determination by sieving)
- ISO 11323 (iron ore vocabulary)
Keywords: ISO 11459, iron ores, certified reference materials, CRM, chemical analysis, homogeneity testing, interlaboratory program, particle size, certification, ISO Guides.