ISO 21687:2007

INTERNATIONAL ISO
STANDARD 21687
First edition
2007-03-01

Carbonaceous materials used in the
production of aluminium —
Determination of density by gas
pyknometry (volumetric) using helium as
the analysis gas — Solid materials
Produits carbonés utilisés pour la production de l'aluminium —
Détermination de la masse volumique vraie par la méthode
pycnométrique gazeuse (volumétrique) utilisant de l'hélium comme gaz
analytique — Matériaux solides




Reference number
ISO 21687:2007(E)
©
ISO 2007

---------------------- Page: 1 ----------------------
ISO 21687:2007(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.


©  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 21687:2007(E)
Contents Page
Foreword. iv
Introduction . v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions. 1
4 Principle. 2
5 Apparatus and materials. 2
6 Sampling, sample preparation and drying.2
7 Procedure . 3
8 Calculation. 3
9 Precision. 4
10 Test report . 5
Bibliography . 6

© ISO 2007 – All rights reserved iii

---------------------- Page: 3 ----------------------
ISO 21687:2007(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 21687 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary
aluminium.
iv © ISO 2007 – All rights reserved

---------------------- Page: 4 ----------------------
ISO 21687:2007(E)
Introduction
This International Standard is based on a DIN method: DIN 51913:2001, Testing of carbon materials —
Determination of density by gas pycnometer (volumetric) using helium as the measuring gas — Solid
materials prepared by Arbeitsausschuß NMP 281, Test Methods for Carbon and Graphite.
The density of calcined petrol coke permits an estimate of the degree of calcination of the analysed material.

© ISO 2007 – All rights reserved v

---------------------- Page: 5 ----------------------
INTERNATIONAL STANDARD ISO 21687:2007(E)

Carbonaceous materials used in the production of aluminium —
Determination of density by gas pyknometry (volumetric) using
helium as the analysis gas — Solid materials
1 Scope
This International Standard specifies a method for the determination of the density of green and calcined
petroleum coke and similar solid materials (e.g. electrodes). This standard is also suitable for hydrocarbons
with a high-temperature boiling range and for other solid materials.
This method is not suitable for graphitized material.
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 3310-1:2000, Test sieves — Technical requirements and testing — Part 1: Test sieves of metal wire cloth
ISO 6257:2002, Carbonaceous materials used in the production of aluminium — Pitch for electrodes —
Sampling
ISO 6375:1980, Carbonaceous materials for the production of aluminium — Coke for electrodes — Sampling
ISO 8007-1:1999, Carbonaceous materials used in the production of aluminium — Sampling plans and
sampling from individual units — Part 1: Cathode blocks
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
density of a solid material
ρ
mass m per unit volume V
m
ρ= (1)
V
where
ρ is the density, expressed in grams per cubic centimetre;
m is the mass, in grams;
V is the volume of the solid, in cubic centimetres, excluding any pore volume.
© ISO 2007 – All rights reserved 1

---------------------- Page: 6 ----------------------
ISO 21687:2007(E)
NOTE Accessible and inaccessible pores contribute to the total pore volume of the solid. However, only accessible
pores can be excluded from the volume of the solid.
4 Principle
A sample is ground and sieved to a size u 0,063 mm. The density ρ is determined volumetrically in a gas
pyknometer with helium as the analysis gas. The mass of the dry test portion is determined an
...