Overview
ISO 12982-1:2000 specifies an ignition temperature method for measuring the reactivity to air of calcined petroleum coke used to make aluminium anodes. The test exposes a prepared coke sample to a controlled air flow in a tube furnace and records the sample temperature vs time to determine the ignition temperature. Empirical correlations are then used to convert ignition temperature into a reactivity value (mass loss per minute) at a reference temperature. The standard supports product specifications, kiln process control and anode butt quality control.
Key topics and requirements
- Scope: Designed for calcined coke used in aluminium anodes; complements a planned Part 2 thermobalance method.
- Sample preparation:
- Sieving into fractions (target grain size 1,0–1,4 mm for test material).
- Mix specified fractions (IIa and IIb); remove oil where present using dichloromethane per ISO 8723.
- Dry to constant mass (110 ± 5 °C) and take a test sample (5,00 ± 0,01 g).
- Apparatus and conditions:
- Vertical single‑zone tube furnace with tube reactor and fritted disc; K‑type (chromel–alumel) thermocouple.
- Air supply (dry), flow typically 50 L/h and regulated pressure (document specifies control to 0,2 MPa).
- Chart recorder or microprocessor to capture temperature vs time.
- Test programs / heating rates:
- Fast method: 10 °C/min - commonly used for petroleum coke specifications.
- Slow method: 0.5 °C/min - used for statistical process control of calcination kilns and anode butt quality control.
- Result determination:
- Ignition temperature is read from the intersection of extrapolated pre‑ and post‑ignition temperature lines.
- Reactivity to air is calculated from the ignition temperature using standardized correlations to give % mass loss per minute at a reference temperature (600 °C for fast, 525 °C for slow).
- Quality & precision:
- Calibration with a certified standard (example ignition ~620 °C at reference heating rate).
- Repeatability and reproducibility limits are provided (precision expressed as absolute °C for ignition and relative % for reactivity).
Applications and users
- Aluminium smelters and anode manufacturers monitoring anode raw material quality and anode butt performance.
- Calcination kiln operators for process control and optimization of calcined coke reactivity.
- Quality laboratories performing product specifications, supplier acceptance testing and R&D on petroleum coke reactivity.
- Consultants and equipment suppliers designing test rigs for carbonaceous materials.
Related standards
- ISO 12982-2 (in preparation) - thermobalance method for reactivity to air.
- ISO 6375 - sampling of coke for electrodes.
- ISO 8723 - determination of oil content (solvent extraction).
- ISO 12984 - particle size distribution of calcined coke.
Keywords: ISO 12982-1, calcined coke, reactivity to air, ignition temperature method, petroleum coke, aluminium anodes, calcination kiln, anode quality control.