Overview
ISO 21079-1:2008 defines the apparatus, reagents and dissolution methods for chemical analysis of AZS refractories - materials containing alumina (Al2O3), zirconia (ZrO2) and silica (SiO2) - specifically for products and raw materials with 5% to 45% ZrO2. It specifies traditional “wet” chemistry, fusion and hydrofluoric-acid dissolution approaches, and prepares samples for instrumental methods such as ICP-AES (inductively coupled plasma atomic emission spectrometry) and FAAS/FAA (flame atomic absorption spectrometry). This part is an alternative to X-ray fluorescence (XRF) methods (see ISO 12677) and does not apply to MgO-based refractories.
Key topics and requirements
- Scope and applicability: AZS refractories containing 5–45% ZrO2; excludes MgO-based products.
- Apparatus and reagents: Lists required laboratory equipment and reagent specifications; emphasizes analytical-grade reagents and purified water.
- Standard solutions: Preparation and standardization procedures for oxide standard solutions (Al2O3, SiO2, ZrO2, TiO2, CaO, MgO, Fe2O3, HfO2, etc.).
- Sampling and LOI: Sampling rules and loss on ignition (LOI) determination referenced to ISO 26845.
- Decomposition and dissolution methods: Multiple decomposition routes to remove bulk silica and liberate analytes:
- Fusion with alkali carbonate and boric acid (followed by dehydration or coagulation to remove SiO2).
- Hydrofluoric acid attack tailored for flame photometry, AA, or ICP-AES.
- Preparation for instrumental analysis: Producing solutions suitable for wet chemical analysis, ICP-AES, and FAAS/FAA.
- Alternative to XRF: Gives validated wet-chemistry and spectrometric alternatives to ISO 12677 XRF methods.
Practical applications and intended users
- Quality control laboratories in refractory manufacturing that test AZS bricks, castables and raw materials.
- Metallurgical and ceramic manufacturers requiring accurate composition data for process control.
- Analytical chemists and materials engineers selecting dissolution routes and preparing samples for ICP-AES or FAAS.
- Standards bodies and test laboratories needing an XRF alternative or cross-validation method.
Practical benefits include reliable oxide determinations (SiO2, Al2O3, ZrO2, TiO2, CaO, MgO, Fe2O3, HfO2, trace alkalis and transition metals) and standardized sample preparation workflows.
Related standards
- ISO 12677 - XRF method for similar AZS refractory analysis (ISO 21079-1 provides alternative methods).
- ISO 26845 - General requirements for wet chemical, AAS and ICP-AES analysis referenced throughout ISO 21079-1.
Keywords: ISO 21079-1:2008, chemical analysis, refractories, AZS, alumina zirconia silica, dissolution methods, fusion, hydrofluoric acid, ICP-AES, FAAS, XRF alternative.