ISO 15906:2007

INTERNATIONAL ISO
STANDARD 15906
First edition
2007-05-01

Carbonaceous materials for the
production of aluminium — Baked
anodes — Determination of the air
permeability
Produits carbonés utilisés pour la production de l'aluminium — Anodes
cuites — Détermination de la perméabilité à l'air



Reference number
ISO 15906:2007(E)
©
ISO 2007

---------------------- Page: 1 ----------------------
ISO 15906:2007(E)
PDF disclaimer
This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but
shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In
downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat
accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.
Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation
parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In
the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.


COPYRIGHT PROTECTED DOCUMENT


©  ISO 2007
All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,
electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or
ISO's member body in the country of the requester.
ISO copyright office
Case postale 56 • CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland

ii © ISO 2007 – All rights reserved

---------------------- Page: 2 ----------------------
ISO 15906:2007(E)
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 has been
established has the right to be represented on that committee. International organizations, governmental and
non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. Draft International Standards
adopted by the technical committees are circulated to the member bodies for voting. Publication as an
International Standard requires approval by at least 75 % of the member bodies casting a vote.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 15906 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary
aluminium.
© ISO 2007 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 15906:2007(E)
Introduction
Anode performance in aluminium reduction cells can be partially characterized by the measurement of the gas
permeability. Higher permeability allows attack and consumption of the anode by air and C0 , thus shortening
2
the life and overall performance of the anode.
iv © ISO 2007 – All rights reserved

---------------------- Page: 4 ----------------------
INTERNATIONAL STANDARD ISO 15906:2007(E)

Carbonaceous materials for the production of aluminium —
Baked anodes — Determination of the air permeability
1 Scope
This International Standard describes a method for the measurement of the air permeability of baked anodes,
by determining the resistance to airflow of a specimen of specified volume at room temperature, within the
range of air permeability between 0,01 nPm (nanoperms) and 10 nPm.
“Green” anodes are considered to be impermeable to gas. Therefore, this test is most applicable to “baked”
carbon material.
NOTE This method can also be used for measuring other carbon materials (e.g. microporous carbon materials), but
precision statements are not available for other carbon materials.
2 Normative references
The following referenced documents are indispensable for the application 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 8007-2:1999, Carbonaceous materials used in the production of aluminium — Sampling plans and
sampling from individual units — Part 2: Prebaked anodes
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
sample
portion of carbon from a baked anode
3.2
test specimen
article prepared from a sample
4 Principle
The air permeability of a sample is determined by a comparative method. The time necessary to draw a
specified volume of air through the test specimen is measured. This time is compared to the time necessary to
draw a specified volume of air through a standard with known air permeability. This comparison yields the air
permeability of the sample material.
5 Apparatus
5.1 Callipers, with 0,01 mm reading precision.
© ISO 2007 – All rights reserved 1

---------------------- Page: 5 ----------------------
ISO 15906:2007(E)
5.2 Air permeability unit equipped as in 5.2.1 to 5.2.3.
5.2.1 Membrane vacuum pump, with an inlet to generate vacuum down to 100 mbar, and an outlet to
generate high pressure up to 4 bar. The maximum flow rate has to reach 25 l/min.
5.2.2 Permeability cell, as shown in Figure 1. The cell is designed to ensure an airtight sealing around the
periphery of the sample. A rubber tube is forced as a seal against the cylindrical test specimen by means of
compressed air. The porous filter-paper and the sponge-rubber protect the vacuum pump from particles
and/or dust from the sample.
5.2.3 U-tube manometer, with light fork sensors as shown in Figure 2.
The U-tube is directly linked with the vacuum pump
...