Overview
ISO 10142:1996 specifies a standardized laboratory method for determining the grain stability of calcined coke used in the production of carbon products for aluminium manufacturing. The standard defines a test procedure using a laboratory vibration mill to assess the mechanical strength and grain stability of calcined coke particles sized between 4 mm and 8 mm. Proper grain stability is critical as coke with poor mechanical strength can degrade during mixing, negatively impacting the quality of baked carbon blocks used in aluminium production.
Developed by ISO Technical Committee ISO/TC 47, Subcommittee SC 7, this method ensures consistent, repeatable testing of calcined coke, supporting quality control and process optimization in aluminium smelting industries.
Key Topics
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Scope and Purpose
Ensures reliable measurement of calcined coke grain stability to avoid degradation during mixing and maintain carbon product quality.
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Testing Equipment
- Laboratory vibration mill equipped with two grinding vessels containing steel balls (1 kg each, diameter 10 mm ± 0.4 mm).
- Oscillation system with an adjustable amplitude of 4 mm ± 0.5 mm and motor speed of 1450-1470 rpm.
- Test sieves of 4 mm and 8 mm mesh sizes complying with ISO 3310-1 standards.
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Sample Preparation
Calcined coke samples are sieved to obtain a 4 mm to 8 mm fraction, with 100 g ± 0.01 g measured for testing per vessel.
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Test Procedure
The prepared sample is subjected to a 3.5-minute grinding action in the vibration mill. After grinding, the material is screened manually between the 4 mm and 8 mm sieves. The mass of particles retained on the 4 mm sieve is measured to calculate grain stability.
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Calculations and Reporting
Grain stability is calculated as the percentage of retained material after vibration milling, averaged over duplicate tests for accuracy. Test reports include sample identification, test details, date, and any anomalies observed.
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Precision
- Repeatability within the same laboratory should not exceed ±2% absolute difference between duplicate tests.
- Reproducibility between different laboratories should not exceed ±3% absolute difference.
Applications
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Aluminium Industry Quality Control
Ensures calcined coke quality by monitoring grain stability to prevent material breakdown during handling and carbon electrode manufacturing.
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Carbon Product Manufacturing
Helps manufacturers optimize production processes by assessing mechanical strength and durability of carbonaceous raw materials.
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Materials Testing Laboratories
Provides a standardized method for consistent testing of calcined coke properties, facilitating comparison of materials from different sources.
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Research and Development
Supports innovation in carbon-based materials by enabling precise characterization of granular stability under controlled vibration conditions.
Related Standards
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ISO 3310-1:1990 – Specifies technical requirements and test procedures for metal wire test sieves used for particle-size analysis, relevant for the sieving stage in this method.
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ISO 6375:1980 – Provides procedures for sampling carbonaceous materials for aluminium production, ensuring representative test samples.
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ISO/TC 47 Standards – A series of standards focusing on chemistry and materials related to aluminium oxide and carbonaceous products for aluminium industry applications.
Keywords: ISO 10142, calcined coke, grain stability, laboratory vibration mill, aluminium production, carbonaceous materials, carbon products, mechanical strength, test procedure, sieve analysis, quality control, aluminium industry standards.
Open preview (PDF)Carbonaceous materials for use in the production of aluminium — Calcined coke — Determination of grain stability using a laboratory vibration mill
