ISO 21078-1:2008

Overview

ISO 21078-1:2008 - Determination of boron(III) oxide in refractory products (Part 1) specifies standardized laboratory methods for measuring total boron(III) oxide (B2O3) in oxidic materials used for ceramics, glass and glazes. The standard applies to mass fractions of 0.01 % or greater and defines sample preparation, analytical procedures, result expression and reporting to ensure reproducible, comparable data across laboratories.

Key topics and technical requirements

• Scope and limits
  • Applicable to oxidic raw materials and refractory products; lower reporting limit 0.01 % B2O3.
• Sample preparation
  • Procedures for sampling, crushing and grinding (sieving to 300 µm then to 106 µm for test sample), drying (110 °C ± 5 °C) and reducing laboratory test portions.
• Number of determinations
  • Simultaneous duplicate determinations and required blank tests for reagent corrections.
• Approved analytical methods
  • Alkaline titrimetry - for samples typically containing > 0.5 % B2O3.
  • Azomethine H absorption spectrophotometry - for 0.01 % to 2.5 % B2O3.
  • Curcumin (rothanocyanine) absorption spectrophotometry - for 0.01 % to 1.0 % B2O3.
  • ICP-AES (inductively coupled plasma atomic emission spectrometry) - for 0.01 % to 15 % B2O3 (extendable to ~30 % with modified fluxes).
• Quality and reagents
  • Use reagents of defined analytical purity and laboratory water conforming to ISO 3696 grade 2; standard solutions and titration procedures are specified.
• Interferences and limitations
  • Noted interferences (e.g., germanium oxide affects alkaline titrimetry) and guidance to use alternative methods when necessary.
• Result calculation and reporting
  • Formulas and instructions for expressing mass fraction as percentage and preparing the test report.

Applications and practical value

• Ensures consistent, validated measurement of B2O3 in raw materials and finished refractory/ceramic/glaze products.
• Supports quality control, incoming material inspection, formulation control for ceramics and glass, and comparative testing between suppliers.
• Useful in materials testing laboratories, production QC labs, R&D groups working on glazes, glass compositions and refractory formulations, and conformity assessment bodies.

Who would use this standard

• Refractory and ceramic manufacturers
• Glass and glaze formulators
• Analytical and materials testing laboratories
• Quality assurance and regulatory compliance teams

Related standards

• ISO 21078-2 (acid extraction method for binder components)
• ISO 3696 (Water for analytical laboratory use)
• ISO 3310-1 (Test sieves)
• ISO 6353-2 / ISO 6353-3 (Reagents for chemical analysis)
• ISO 836 (Refractories - Vocabulary)

Keywords: ISO 21078-1:2008, boron(III) oxide, B2O3 determination, refractory products, ceramics, glass, azomethine H, curcumin spectrophotometry, alkaline titrimetry, ICP-AES, sample preparation.