Overview - ISO 12989-1:2000 (loss-in-mass method)
ISO 12989-1:2000 defines a standardized loss-in-mass method to determine the reactivity to air of carbonaceous materials used in aluminium production, specifically baked anodes and sidewall blocks. The method quantifies how much anode material burns away when exposed to air at controlled temperatures and provides reproducible metrics (residue, dust, loss) useful for quality control, material specification and process prediction in aluminium smelting.
Key topics and technical requirements
- Scope: Test procedure developed especially for anodes used in aluminium reduction.
- Principle: Heat a cylindrical core to 550 °C, then cool at 15 °C/h to 400 °C while flowing dry air and agitating the sample to collect dust. Report residual mass, collected dust and total mass loss as percentages.
- Sampling & specimen: Core diameter (50 ± 1) mm, length (60 ± 1) mm; dry at (120 ± 5) °C for 12 h; drill a 7 mm hole to specified depth. Sampling may follow ISO 8007-2.
- Apparatus: Muffle furnace with specified tube dimensions; programmable temperature controller; cam agitation (1 r/min, 5 mm fall); K-type thermocouple (chromel‑alumel); gas flow meter and pressure control (air at ~0.2 MPa, 200 L/h); tumbling apparatus and sieves to separate dust.
- Procedure highlights: Preheat to 550 °C, start air after 30 min, maintain flow until temperature reaches 400 °C (approx. 10 h), stop air, cool to 300 °C before removal, tumble specimen 20 min and sieve.
- Calculations: Express residue, dust and loss as percent of initial mass using the standard formulae; report to 0.1 g accuracy.
- Precision & reproducibility: Repeatability depends on core homogeneity; inter-laboratory reproducibility estimates are provided and intended for use when characterizing electrode populations (≥ 30 cores).
- Test report: Must include sample ID, reference to ISO 12989-1, sampling method, date, results, any anomalies and deviations.
Applications and users
ISO 12989-1 is used for:
- Quality control in aluminium smelters and carbon product manufacturing.
- Incoming material inspection for baked anodes and sidewall blocks.
- R&D and process optimisation teams assessing anode stability and burn-off.
- Third‑party testing laboratories and certification bodies verifying material conformity.
Keywords: anode reactivity test, carbonaceous materials, aluminium production, loss-in-mass method.
Related standards
- ISO 12989 (series) - Part 2 anticipated for the thermogravimetric (TGA) method.
- ISO 8007-2 - sampling plans and sampling for prebaked anodes (referenced normative standard).
- IEC 60584-2 - thermocouple tolerances (referenced for temperature measurement).
This standard helps aluminium industry stakeholders measure and compare anode reactivity to air reliably, supporting material selection, process control and product specification.
Open preview (PDF)Carbonaceous materials used in the production of aluminium — Baked anodes and sidewall blocks — Determination of the reactivity to air — Part 1: Loss in mass method
