ISO 5071-1:1997

IS0
INTERNATIONAL
5071-l
STANDARD
First edition
1997-08-01
Brown coals and lignites - Determination
of the volatile matter in the analysis
sample -
Part 1:
Two-furnace method
Charbons bruns et /ignites - DBtermina tion des ma t&es vola tiles dans
khantillon pour analyse -
Partie 1: Mbthode avec utilisation de deux fours
Reference number
IS0 50714:1997(E)

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IS05071=1:1997(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work of
preparing International Standards is normally carried out through IS0
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. IS0
collaborates closely with the International Electrotechnical Commission
(IEC) on all matters of electrotechnical standardization.
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.
International Standard IS0 5071-l was prepared by Technical Committee
lSO/lC 27, So/id mineral fuels, Subcommittee SC 5, Methods of analysis.
IS0 5071 consists of the following part, under the general title Brown
Determination of volatile matter in the analysis
coals and /ignites -
sample:
Part 1: Two-furnace method
0 IS0 1997
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 the publisher.
lnternational Organization for Standardization
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Printed in Switzerland
ii

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IS0 5071=1:1997(E)
Introduction
The volatile matter is determined as the loss in mass, corrected for
moisture, when an analysis sample of brown coal or lignite is heated out of
contact with air under specified conditions. The test is empirical and, in
order to obtain reproducible results, it is essential that the rate of heating,
the final temperature and the overall duration of the test be carefully
controlled. Due to the nature of brown coals and Iignites, initial heating of
the sample at 400 “C is necessary to minimize the possibility of ejection of
sample from the test crucible.
Mineral matter associated with the sample may also lose mass under the
conditions of the test, the magnitude of the loss being dependent on both
the nature and the quantity of the minerals present.

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IS0 5071=1:1997(E)
INTERNATIONAL STANDARD @ IS0
Determination of the volatile matter
Brown coals and lignites -
in the analysis sample -
Part 1:
Two-furnace method
1 Scope
This part of IS0 5071 specifies a method of determining the volatile matter of brown coals and Iignites.
2 Normative references
The following standards contain provisions which, through reference in this text, constitute provisions of this part of
IS0 5071. At the time of publication, the editions indicated were valid. All standards are subject to revision, and
parties to agreements based on this part of IS0 5071 are encouraged to investigate the possibility of applying the
most recent editions of the standards indicated below. Members of IEC and IS0 maintain registers of currently valid
International Standards.
IS0 1170:1977, Coal and coke - Calculation of analyses to different bases - Vocabulary.
IS0 1213-2:1992, Solid mineral fuels - Part 2: Terms relating to coal sampling and analysis.
IS0 5068: 1983, Brown coals and /ignites - Determination of moisture content - Indirect gravimetric method.
IS0 5069-2:1983, Brown coals and /ignites - Principles of sampling - Pafl2: Sample preparation for
determination of moisture content and for general analysis.
, 3 Definitions
For the purposes of this part of IS0 5071, the definitions given in IS0 1213-2 apply.
4 Principle
The coal is heated out of contact with air for 7 min at 400 “C, then immediately transferred to another furnace
and heated at 900 OC for a further 7 min. The percentage of volatile matter is calculated from the loss in mass of the
oven-dried sample or from the loss in mass of the analysis sample corrected for moisture.
1

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5 Reagents
Desiccants, fresh or freshly regenerated and preferably self-indicating. Suitable desiccants are magnesium
5.1
perchlorate, silica gel, activated alumina and anhydrous calcium sulfate.
VVARNING - Magnesium perchlorate is a strong oxidizing agent. Do not attempt to regenerate the
absorbent. Do not permit contact with organic materials or reducing agent.
5.2 Nitrogen, dry, with a maximum oxygen content of 30 urn per litre.
6 Apparatus
6.1 Furnace, (figure 1) heated by electricity. Two such furnaces are required. One furnace shall have a zone of
160 mm x 100 mm maintained at a uniform temperature of 400 “C + IO OC. The second shall have a zone of
160 mm x 100 mm maintained at a uniform temperature of 900 “C + 5 “C. The furnaces may be the stop-ended type
or fitted at the back with a flue approximately 25 mm in diameter by 150 mm long.
The heat capacity of the 900 “C and/or 400 “C furnace shall be such that, with an initial temperature of 900 “C
and/or 400 “C, a temperature of 900 “C + IO “C and/or 400 “C + IO “C is regained within 4 min after insertion of a
cold stand and its crucibles. The temperature shall be measured with a thermocouple as described in 6.3. The
furnace can be designed specifically either for multiple determinations using a number of crucibles in one stand or
for receiving one crucible and its stand. A position for the crucible stand shall be chosen within the zone of uniform
temperature and this position used for all determinations.
Dimensions in millimetres
A- Flue
Chamber-width 200
\
,--- Thermocouple
,!-- Heating system
Figure 1 - Example of a suitable furnace
2

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IS0 5071=1:1997(E)
6.2 Oven, capable of being controlled at a temperature within the range 105 OC to 110 OC and with prevision for
passing a current of dry oxygen-free nitrogen through it at a rate sufficient to change the atmosphere 15 times per
hour. The size of the chamber is suitable for containing the crucible (6.4).
6.3 Thermocouple, the temperature characteristics of the furnace shall be checked with an unsheathed
thermocouple, of wire not thicker than 1 mm. The thermo-junction shall be inserted midway between the base of the
crucible in its stand and the floor of the furnace. If the stand holds more than one crucible, the temperature under
each crucible shall be checked in the same manner. If desired, a sheathed thermocouple may be permanently
installed in the furnace with its thermo-junction as close as possible to the centre of the zone of uniform
temperature; in this case, its temperature readings shall be correlated at frequent intewals with those of the
unsheathed thermocouple, which is then inserted on
...