ISO 22731:2020

Overview

ISO 22731:2020 specifies a laboratory method for determining the resistance to physical abrasion of cathode samples used in the production of aluminium. The standard defines the test principle, required apparatus, sampling dimensions, test procedure, calculation of abrasion loss (expressed as a percentage), and reporting requirements. It is intended to provide a repeatable measure of cathode wear under controlled abrasive conditions.

Key Topics and Requirements

• Scope: Method for measuring cathode abrasion resistance for carbonaceous materials used in aluminium production.
• Sampling: Follow ISO 8007-1; core sample size 50 ± 0.2 mm diameter × 20 ± 0.2 mm length.
• Apparatus
  • Caliper: 0–150 mm range with ±20 µm accuracy for dimensions ≤ 100 mm.
  • Grinding/polishing apparatus with sample holder and powerhead.
  • Abrasive disc: silicon carbide (SiC), grit size 60.
• Operational settings
  • Abrasive disc speed: 200 rpm.
  • Head speed: 100 rpm (opposite rotation to the base).
  • Head force on sample: 50 N.
  • Test duration: 30 s for 100% graphite and graphitized grades; 60 s for other grades.
• Measurement & Calculation
  • Measure core height before and after abrasion to 0.01 mm.
  • Abrasion A (%) = ((l1 − l2) / l1) × 100, where l1 = height before test, l2 = height after test.
• Precision: No interlaboratory precision data available in the document.
• Test report must include sample identification, reference to ISO 22731:2020, method, test date, results, and any deviations or unusual observations.

Applications and Users

Practical uses of ISO 22731:2020 include:

• Quality control for industrial cathode blocks in aluminium smelting operations.
• Material selection and comparative testing by suppliers of carbonaceous cathode materials.
• R&D and product development teams evaluating abrasion resistance of new cathode formulations.
• Independent testing laboratories performing standardized abrasion tests for suppliers or smelters.
• Asset management and failure analysis teams estimating cathode lifetime and wear behaviour.

Keywords: ISO 22731:2020, cathode abrasion testing, abrasion resistance, carbonaceous cathode, aluminium production, silicon carbide abrasive, cathode sampling.

Related Standards

• ISO 8007-1 - Carbonaceous materials used in the production of aluminium - Sampling plans and sampling from individual units - Part 1: Cathode blocks (referenced for sampling methodology).

This standard provides a clear, repeatable lab procedure to quantify cathode wear, enabling consistent comparisons across materials and supporting better lifecycle and quality decisions in aluminium production.