Overview - ISO 20565-2:2008 (Wet chemical analysis)
ISO 20565-2:2008 specifies traditional "wet process" analytical methods for the chemical analysis of chrome-bearing refractory products and chrome-bearing raw materials as an alternative to X‑ray fluorescence (XRF). It sets out reagent procedures, titrimetric and colorimetric tests, spectrophotometric measurements and calibration/blanking requirements for routine laboratory determination of major and minor oxide components. The part complements ISO 20565‑1 (apparatus, reagents and dissolution) and ISO 20565‑3 (FAAS/ICP‑AES).
Key topics and technical requirements
- Scope and applicability: Methods are applicable to components within specified ranges (Table 1), e.g. MgO 15–85%, Cr2O3 2–60%, Al2O3 2–30%, SiO2 0.5–10%, Fe2O3 0.5–25%, plus TiO2, MnO, CaO, Na2O, K2O, ZrO2, P2O5 and LOI.
- Silicon(IV) oxide (SiO2): Two colorimetric approaches - combined coagulation/dehydration with the molybdenum‑blue reaction (and a dedicated molybdenum‑blue method). Includes calibration, blank tests and absorbance measurement at 650 nm.
- Aluminium oxide (Al2O3): Two separation/titrimetric options - CyDTA‑zinc back‑titrimetric method (cation‑exchange separation) and cupferron extraction followed by CyDTA back‑titration; procedures include pH control, complexation, and titration end‑point detection with xylenol orange.
- Other determinands and methods:
- Fe2O3 (total iron as Fe2O3), TiO2, MnO, CaO, MgO - classical wet chemistry/titrimetric routes.
- Na2O and K2O - flame photometry / flame spectrophotometry.
- Cr2O3 - dedicated wet chemical determination.
- ZrO2 - xylenol orange absorption spectroscopy.
- P2O5 - molybdenum blue method for phosphate.
- Quality controls: Calibration graphs, blank tests, replicate absorbance checks, and specified aliquot volumes and reagent volumes are required to ensure accuracy and repeatability.
Applications and users
- Intended for industrial and laboratory quality control of refractories and raw materials where XRF is not available or as a confirmatory alternative.
- Primary users:
- Refractory manufacturers and raw‑material suppliers
- Metallurgical plants and ceramic producers
- Chemical and materials testing laboratories
- Standards and conformity assessment bodies
- Practical benefits: low‑cost instrumentation compared with XRF/ICP, established wet‑chemistry techniques for routine compositional analysis and contractual testing.
Related standards
- ISO 20565‑1:2008 - Apparatus, reagents, dissolution and gravimetric silica
- ISO 20565‑3:2008 - FAAS and ICP‑AES methods (instrumental alternatives)
- ISO 26845:2008 - General requirements for wet chemical analysis, AAS and ICP‑AES methods
Keywords: ISO 20565-2:2008, wet chemical analysis, chrome-bearing refractory products, chrome-bearing raw materials, molybdenum blue, CyDTA, cupferron, flame photometry, ZrO2 xylenol orange.