Overview
ISO 16206:2025 - "Phase quantitative analysis of residual quartz in silica bricks - X‑ray diffraction method" specifies a repeatable X‑ray diffraction (XRD) procedure to quantify alpha‑quartz (residual quartz) in silica bricks. The method is designed for mass fractions in the range 0.3 % to 5.0 %, using a Bragg‑Brentano diffractometer and an external‑standard working curve. The standard covers sample preparation, measurement parameters, working‑curve establishment and reporting; it does not address health and safety controls for respirable dust.
Key topics and technical requirements
- Scope and range: Quantitative phase analysis of alpha‑quartz in silica bricks (0.3–5.0 % mass fraction).
- Measurement principle: External‑standard XRD using the <101> diffraction peak of alpha‑quartz; peak area proportional to phase content.
- Sample preparation: Remove outer layers, crush, quarter and grind to particle size ≤ 0.030 mm; dry reference materials at (110 ± 5) °C.
- Reference materials: High‑purity alpha‑quartz standards (e.g., NIST 1878b) or qualified series materials (e.g., GSB S2021004) with ≥95 % alpha‑quartz for working‑curve preparation.
- Working curve: Prepare mixtures (examples: 0.5, 1.0, 2.0, 3.0, 4.0, 5.0 %) and measure five test pieces per mixture; establish a curve through the origin correlating peak area to alpha‑quartz content.
- XRD parameters: Bragg‑Brentano geometry; scan range adequate to include the <101> peak (start/end 2θ values provided for Cu and Co tubes); scanning speed ≤ 1°/min; ensure ≥5 000 counts on the largest peaks to improve peak fitting.
- Replicates and reporting: Five test pieces per item, mean value rounded to 0.1 %; test report must reference ISO 16206:2025 and include sample, instrument and result details.
- Quality data: Annex A contains round‑robin precision statistics; Annex B describes instrument and method detection/quantification limits.
Applications
- Quality control and acceptance testing of silica bricks in manufacturing and procurement.
- Laboratory testing for material characterization and batch verification.
- Comparative studies across suppliers using standardized XRD quantification of residual alpha‑quartz.
Who should use this standard
- Refractory manufacturers and quality assurance teams
- Independent testing and materials characterization laboratories
- Research groups studying refractory phases
- Procurement and compliance personnel specifying silica brick composition
Related standards
- ISO 836 - Terminology for refractories
- ISO 5022 - Sampling and acceptance testing of shaped refractory products
- ISO 23071:2021 - XRD determination of reduced species in carbon‑containing refractories
Note: ISO 16206:2025 does not mandate safety procedures. Users must implement appropriate respiratory protection and dust controls when grinding and handling silica brick powders.
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