ISO 12988-1:2000

INTERNATIONAL ISO
STANDARD 12988-1
First edition
2000-05-01
Carbonaceous materials used in the
production of aluminium — Baked
anodes — Determination of the reactivity to
carbon dioxide —
Part 1:
Loss in mass method
Produits carbonés utilisés pour la production de l'aluminium — Anodes
cuites — Détermination de la réactivité au dioxyde de carbone —
Partie 1: Méthode par perte de masse
Reference number
ISO 12988-1:2000(E)
©
ISO 2000

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ISO 12988-1:2000(E)
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ISO 12988-1:2000(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 3.
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 part of ISO 12988 may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 12988-1 was prepared by Technical Committee ISO/TC 47, Chemistry, Subcommittee
SC 7, Aluminium oxide, cryolite, aluminium fluoride, sodium fluoride, carbonaceous products for the aluminium
industry.
ISO 12988 consists of the following parts, under the general title Carbonaceous materials used in the production of
aluminium — Baked anodes — Determination of the reactivity to carbon dioxide:
� Part 1: Loss in mass method
A thermogravimetric method will be the subject of a future part 2 to ISO 12988.
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ISO 12988-1:2000(E)
Introduction
Carbon reacts with carbon dioxide according to the following equation:
CC��O 2CO
2
The loss of anode material from reaction with CO under certain constant conditions, as well as the mass of the
2
remaining specimen and of the dust resulting from selective burning, are of importance in predicting the behaviour
of the anodes in the electrolysis cell.
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INTERNATIONAL STANDARD ISO 12988-1:2000(E)
Carbonaceous materials used in the production of aluminium —
Baked anodes — Determination of the reactivity to carbon
dioxide —
Part 1:
Loss in mass method
1 Scope
This part of ISO 12988 specifies a loss in mass method for the determination of the reactivity of carbonaceous products
to carbon dioxide. This method was developed especially for baked anodes used in the production of aluminium.
2 Normative references
The following normative documents contain provisions which, through reference in this text, constitute provisions of
this part of ISO 12988. For dated references, subsequent amendments to, or revisions of, any of these publications
do not apply. However, parties to agreements based on this part of ISO 12988 are encouraged to investigate the
possibility of applying the most recent editions of the normative documents indicated below. For undated
references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 8007-2:1999, Carbonaceous materials used in the production of aluminium — Sampling plans and sampling
from individual units — Part 2: Prebaked anodes.
IEC 60584-2, Thermocouples — Part 2: Tolerances.
3Principle
A baked test cylinder is placed in a furnace purged with carbon dioxide, CO , at a temperature of 960 °C for 7 h. The
2
loss in mass is determined and the dust produced is measured using a tumbling-apparatus. The residual body of the
test cylinder, called the unreacted residue, is weighed and all results calculated in mass percent.
4 Reagent
4.1 Carbon dioxide,(CO ) having a minimum purity of 99,5 % by volume and impurities of
2
� N � Ar� 0,5 % by volume,
2
3
� H O� 150 mg/m .
2
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ISO 12988-1:2000(E)
5 Apparatus
A diagram showing a typical apparatus in accordance with specifications is shown in Figure 1.
Normal ordinary apparatus and in particular the following:
5.1 Muffle furnace, having the dimensions given in Figure 2 with a vertical, single-zone tube ensuring good,
vertical temperature distribution and capable of heating to a maximum temperature of at least 1 000 °C as well as
maintaining the temperature at (960� 2) °C.
5.2 Sample holder, made of heat-resistant steel to support the two test specimens in the centre of the furnace
with a collection plate incorporated for ca
...