ISO 2961:1974

Overview

ISO 2961:1974 - "Aluminium oxide primarily used for the production of aluminium - Determination of an adsorption index" specifies standardized laboratory procedures to measure the adsorptive power of industrial, calcined aluminium oxide (alumina). The standard defines two complementary test methods: a carbon tetrachloride vapour method for materials with density > 3.75 g/ml, and a water‑vapour method for materials with density < 3.75 g/ml. Results are reported as an adsorption index per 100 g of alumina dried at 300 °C. This International Standard has also been approved by IUPAC.

Key Topics and Requirements

• Scope: Applicable to industrial calcined aluminium oxide used in aluminium production; evaluates vapour adsorption on powdered solids.
• Two methods:
  • Carbon tetrachloride vapour method (for density > 3.75 g/ml)
    • Exposure to CCl4 vapour at 25 ± 0.5 °C for 2 h.
    • Drying at 300 ± 10 °C; calculation uses mass differences and the density of CCl4 (1.594 g/mL at 25 °C) to express adsorption as millilitres per 100 g dried alumina.
    • Apparatus: squat weighing bottle, desiccator/vessel with perforated support plate, electric oven.
  • Water vapour method (for density < 3.75 g/ml)
    • Pre‑treatment and high‑temperature drying of sample support (1000–1100 °C).
    • Humidity exposures: 30 min at 100% RH then 1 h 45 min at 44% RH (potassium carbonate solution used to establish 44% RH).
    • Result expressed as grams of water adsorbed per 100 g dried alumina.
    • Apparatus: humidity cabinet, desiccators, electric ovens and furnaces, platinum dish for sample.
• Environmental and procedural controls: precise temperature and humidity control (e.g., 25 ± 0.5 °C exposure temperature); careful mass measurements to 0.001 g or 0.01 g depending on step.
• Expression of results: Standardized calculations based on mass differences; results normalized to 100 g of alumina dried at 300 °C.

Applications

• Quality control and specification testing of calcined aluminium oxide (alumina) used in aluminium smelting and refining.
• Comparative evaluation of alumina texture, surface area proxies, and adsorptive behavior relevant to process performance.
• Useful in production control for suppliers of industrial alumina and in acceptance testing by aluminium producers.

Who Would Use This Standard

• Analytical and QC laboratories in the alumina and aluminium industries
• Alumina producers specifying product performance
• Materials scientists and process engineers concerned with feedstock compatibility
• Standards bodies and accreditation laboratories validating test methods

Related Standards

• ISO/R 802 (Preparation and storage of test samples) - referenced by ISO 2961.
• Note: ISO 2961:1974 is IUPAC‑approved; consult current ISO catalogues for revisions or related alumina testing standards.