ISO 17544:2024

Carbonaceous materials used in the production of aluminium - Cold and tepid ramming pastes - Determination of rammability of unbaked pastes

This document describes a method of producing a compaction curve indicating the rammability of carbonaceous ramming pastes used to line cathodes utilized in the production of aluminium. Determination of the rammability enables a ramming paste with the optimum density to be selected.

Produits carbonés utilisés pour la production de l'aluminium — Pâtes de brasquage froides et tièdes — Détermination de l'aptitude au brasquage des pâtes non cuites

General Information

• Status: Published
• Publication Date: 31-Jul-2024
• ICS: 71.100.10 - Materials for aluminium production
• Technical Committee: ISO/TC 226 - Materials for the production of primary aluminium
• Drafting Committee: ISO/TC 226 - Materials for the production of primary aluminium
• Current Stage: 6060 - International Standard published
• Start Date: 01-Aug-2024
• Due Date: 28-Aug-2024
• Completion Date: 01-Aug-2024

Relations

• Revises: ISO 17544:2004 - Carbonaceous materials used in the production of aluminium - Cold and tepid ramming pastes - Determination of rammability of unbaked pastes
• Effective Date: 04-Mar-2023

Overview

ISO 17544:2024 is an international standard developed by ISO for the assessment of carbonaceous materials used in the production of aluminium, specifically focusing on cold and tepid ramming pastes. This second edition revises the method to determine the rammability of unbaked carbonaceous pastes, which are crucial for lining cathode blocks in aluminium electrolysis cells. The standard provides a reliable laboratory procedure to generate a compaction curve, enabling selection of ramming pastes with optimum density characteristics essential for efficient and disturbance-free aluminium production.

The standard outlines a precise laboratory method involving a controlled compaction test and data analysis based on a Weibull distribution function. This ensures reproducible and accurate evaluation of the paste’s physical behavior under mechanical impacts, directly influencing the quality and longevity of aluminium smelting cells.

Key Topics

• Scope and Purpose
  Defines a method to assess rammability by creating compaction curves representing density changes under repeated impacts, critical for selecting suitable unbaked paste in aluminium production.

• Testing Principle
  Cold or tepid ramming pastes are subjected to 350 impacts via a standardized rammer device. The height reduction of the paste specimens is measured to calculate density changes as a function of the number of impacts.

• Apparatus Requirements
  Includes a steel rammer cylinder, a falling weight apparatus with precise mass and drop height, temperature-controlled environments, and accurate weighing and measuring devices to maintain consistency and repeatability.

• Data Analysis
  Utilizes fitting of experimental compaction data to a three-parameter cumulative Weibull distribution, facilitating interpretation of paste behavior and enabling calculation of the ramming parameter N2 - the number of impacts at which the paste compaction rate critically changes.

• Key Performance Indicators

  • Ramming Parameter (N2): Indicates paste rammability, with typical values between 65 and 130 impacts.
  • Density Ratio (ρ(50)/ρ(100)): An alternative metric for quick rammability assessment using density after 50 and 100 impacts.

• Precision and Repeatability
  Prescribes reproducibility and repeatability standards following ISO 5725-2 guidelines to ensure reliability across laboratories.

• Test Reporting
  Detailed test reports must document sample identification, temperature conditions, test results including compaction curves, Weibull parameters, and any deviations or special observations.

Applications

ISO 17544:2024 serves multiple practical applications within the aluminium production industry:

• Cathode Lining Quality Control
  Enables manufacturers and smelters to select ramming pastes with optimal compaction properties, reducing leakage risks and ensuring durable cathode lining performance.

• Material Development and Testing
  Assists suppliers in formulating ramming pastes tailored for efficient compaction behavior, enhancing overall process stability in aluminium electrolysis.

• Process Optimization
  Provides aluminium plants with a method to benchmark paste quality and adjust operational parameters, such as ramming technique and paste temperature, for improved pot lining integrity.

• Research and Standardization Compliance
  Supports laboratories conducting performance testing of new carbonaceous materials, maintaining compliance with international standards and enabling consistent product evaluation globally.

Related Standards

• ISO 14422 – Carbonaceous materials used in aluminium production: Cold-ramming pastes sampling methods
  Provides guidelines on sampling ramming pastes to ensure representative test specimens for rammability evaluation.

• ISO 5725-2 – Accuracy (trueness and precision) of measurement methods and results: Basic method for determining repeatability and reproducibility
  Details statistical procedures for establishing the precision of test methods, directly referenced in ISO 17544.

• ISO/TC 226 – Technical committee responsible for materials used in primary aluminium production
  Oversees the development and maintenance of standards related to carbonaceous materials and other aluminium production inputs.

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Keywords: ISO 17544, ramming pastes, aluminium production, carbonaceous materials, rammability test, compaction curve, cathode lining, cold ramming paste, tepid ramming paste, Weibull distribution, aluminium electrolysis, powder density, material testing, industrial standards, ramming parameter, aluminium smelting, ISO standards.

Standards Content (Sample)

International
Standard
ISO 17544
Second edition
Carbonaceous materials used in
2024-08
the production of aluminium —
Cold and tepid ramming pastes —
Determination of rammability of
unbaked pastes
Produits carbonés utilisés pour la production de l'aluminium —
Pâtes de brasquage froides et tièdes — Détermination de
l'aptitude au brasquage des pâtes non cuites
Reference number
© ISO 2024
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
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or ISO’s member body in the country of the requester.
ISO copyright office
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Phone: [phone]
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Website: www.iso.org
Published in Switzerland
ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Symbols . 1
5 Principle . 2
6 Apparatus . 2
7 Sampling . 2
8 Procedure . 3
9 Expression of results . 3
9.1 Calculation of the density .3
9.2 Interpretation of the curve .3
9.3 Determination of N .3
9.3.1 Fitting the data to a Weibull function .3
9.3.2 Calculation of N .4
9.4 Determination of ρ(50)/ρ(100) .4
10 Precision . 4
11 Test report . 5

iii
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
bodies (ISO member bodies). The work of preparing International Standards is normally carried out through
ISO technical committees. Each member body interested in a subject for which a technical committee
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with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
The procedures used to develop this document and those intended for its further maintenance are described
in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the different types
of ISO document should be noted. This document was drafted in accordance with the editorial rules of the
ISO/IEC Directives, Part 2 (see www.iso.org/directives).
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For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and expressions
related to conformity assessment, as well as information about ISO's adherence to the World Trade
Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 226, Materials for the production of primary
aluminium.
This second edition cancels and replaces the first edition (ISO 17544:2004), which has been technically
revised.
The main changes are as follows:
— the mass of the falling weight and the ramming rate have been corrected.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www.iso.org/members.html.

iv
Introduction
The bottom of aluminium electrolysis cells is lined with cathode blocks that are sealed with a ramming
paste to avoid any leakage. When lining a cell, the green paste is directly rammed between the cathode
blocks and baked in situ during the start-up of the pot by the process heat. The quality of the paste is of
primary importance as to ensure long operation without disturbance.

v
International Standard ISO 17544:2024(en)
Carbonaceous materials used in the production of
aluminium — Cold and tepid ramming pastes —
Determination of rammability of unbaked pastes
1 Scope
This document describes a method of producing a compaction curve indicating the rammability of
carbonaceous ramming pastes used to line cathodes utilized in the production of aluminium.
Determination of the rammability enables a ramming paste with the optimum density to be selected.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated references,
the latest edition of the referenced document (including any amendments) applies.
ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results — Part 2: Basic method for
the determination of repeatability and reproducibility of a standard measurement method
ISO 14422, Carbonaceous materials used in
...