Hard coal -- Audibert-Arnu dilatometer test

This document specifies a method for determining the swelling properties of hard coal when heated under standard conditions in a dilatometer.

Houille -- Essai au dilatomètre Audibert-Arnu

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Status
Published
Publication Date
12-Jan-2020
Current Stage
6060 - International Standard published
Start Date
13-Dec-2019
Completion Date
13-Jan-2020
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ISO 349:2020 - Hard coal -- Audibert-Arnu dilatometer test
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INTERNATIONAL ISO
STANDARD 349
Second edition
2020-01
Hard coal — Audibert-Arnu
dilatometer test
Houille — Essai au dilatomètre Audibert-Arnu
Reference number
ISO 349:2020(E)
ISO 2020
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ISO 349:2020(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2020

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Published in Switzerland
ii © ISO 2020 – All rights reserved
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ISO 349:2020(E)
Contents Page

Foreword ........................................................................................................................................................................................................................................iv

Introduction ..................................................................................................................................................................................................................................v

1 Scope ................................................................................................................................................................................................................................. 1

2 Normative references ...................................................................................................................................................................................... 1

3 Terms and definitions ..................................................................................................................................................................................... 1

4 Principle ........................................................................................................................................................................................................................ 2

5 Apparatus ..................................................................................................................................................................................................................... 3

5.1 Apparatus for preparing the coal pencil ........................................................................................................................... 3

5.2 Dilatometer and accessories ....................................................................................................................................................... 3

5.3 Other apparatus ..................................................................................................................................................................................... 3

5.4 Calibration of apparatus ................................................................................................................................................................. 4

5.5 Inspection .................................................................................................................................................................................................... 4

5.5.1 Dilatometer ........................................................................................................................................................................... 4

5.5.2 Mould ......................................................................................................................................................................................... 4

6 Preparation of sample .................................................................................................................................................................................... 5

7 Procedure..................................................................................................................................................................................................................... 5

7.1 Preparation of the coal pencil .................................................................................................................................................... 5

7.2 Determination of dilatation ......................................................................................................................................................... 6

7.3 Cleaning of the tube and piston ................................................................................................................................................ 6

7.3.1 Tube and plug ..................................................................................................................................................................... 6

7.3.2 Piston ......................................................................................................................................................................................... 6

8 Expression of results ........................................................................................................................................................................................ 6

9 Precision of determination ........................................................................................................................................................................ 7

9.1 Repeatability ............................................................................................................................................................................................. 7

9.2 Reproducibility ....................................................................................................................................................................................... 7

10 Test report ................................................................................................................................................................................................................... 7

Annex A (informative) Types of dilatation curves .................................................................................................................................. 8

Annex B (informative) Inspection of dilatometer tubes................................................................................................................... 9

Bibliography .............................................................................................................................................................................................................................15

© ISO 2020 – All rights reserved iii
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ISO 349:2020(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.

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 documents 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).

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. Details of

any patent rights identified during the development of the document will be in the Introduction and/or

on the ISO list of patent declarations received (see www .iso .org/ patents).

Any trade name used in this document is information given for the convenience of users and does not

constitute an endorsement.

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 27, Solid mineral fuels, Subcommittee

SC 5, Methods of analysis.

This second edition cancels and replaces the first edition (ISO 349:1975), which has been technically

revised. The main changes are the following:
— Reformatting of the figures in the main document and annexes.

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 © ISO 2020 – All rights reserved
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ISO 349:2020(E)
Introduction

The Audibert-Arnu dilatometer test is used to determine the coking properties of hard coal or hard coal

blends on the laboratory scale.

In principle, the test is not designed, nor can it be used, to indicate the pressures exerted by hard coals

on the walls of industrial carbonization ovens.
© ISO 2020 – All rights reserved v
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INTERNATIONAL STANDARD ISO 349:2020(E)
Hard coal — Audibert-Arnu dilatometer test
1 Scope

This document specifies a method for determining the swelling properties of hard coal when heated

under standard conditions in a dilatometer.
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 1213-2, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and analysis

3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 1213-2 and the following apply.

3.1
softening temperature
temperature of initial contraction
temperature at which the downward movement of the dilatometer piston is 0,5 mm
Note 1 to entry: See temperature T in Figure 1.
3.2
temperature of maximum contraction
temperature at which the dilatometer piston reaches its lowest point
Note 1 to entry: See temperature T in Figure 1.
3.3
temperature of maximum dilatation
temperature at which the dilatometer piston reaches its highest point
Note 1 to entry: See temperature T in Figure 1.
3.4
maximum contraction

maximum downward movement of the dilatometer piston, measured from the zero point

Note 1 to entry: Maximum contraction is expressed as a percentage of the initial test-piece length.

Note 2 to entry: See a in Figure 1.
3.5
maximum dilatation

maximum upward movement of the dilatometer piston after contraction, measured from the zero point

Note 1 to entry: Maximum dilatation is expressed as a percentage of the initial test-piece length.

Note 2 to entry: See b in Figure 1. The value can be either positive or negative.

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ISO 349:2020(E)
3.6
repeatability

maximum acceptable difference between two determinations which are carried out in the same

laboratory, by the same operator with the same apparatus, on test pieces prepared from the same test

sample and tested simultaneously in two different retorts during the same heating cycle or separately

in the same retort during different heating cycles
3.7
reproducibility

maximum acceptable difference between the means of two determinations which are carried out in

each of two laboratories, on representative portions taken from the same gross sample, after the last

stage of sample preparation
4 Principle

A pencil made of powdered (pulverised) coal formed under pressure is inserted into a precisely

calibrated narrow tube and topped by a calibrated steel rod (piston) which slides in the bore of the tube.

The whole assembly including the tube, pencil and piston is heated at a constant and definite rate.

Upon taking regular readings of the displacement of the piston as a function of the temperature and

expressing the displacements observed as percentages of the original length of the pencil, a curve of the

type shown in Figure 1 can be plotted.
Key

T temperature at which the piston has moved down 0,5 mm (or one division, if the scale is calibrated in percentage

of the standard length of pencil) softening temperature or initial contraction temperature

T temperature at which the piston reaches its lowest point: temperature of maximum contraction

T temperature at which the piston reaches its highest point: temperature of maximum dilatation

Y piston displacement (or dilatation) in %
a maximum contraction of length of pencil in %.
b maximum dilatation of length of pencil, %.
Figure 1 — Piston displacement with temperature
Different types of dilatation curves are represented in Annex A.

NOTE The principal factors capable of distorting the results of this empirical test are the following:

a) Deterioration/oxidation of the coal, consequent on bad storage or faulty drying;

b) Deviation from the tolerances of
2 © ISO 2020 – All rights reserved
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ISO 349:2020(E)
1) the internal dimensions of the dilatometer tube,
2) the clearance between tube and piston,
3) the mass of the piston,
4) the dimensions of the mould;
c) Deviation from the specified mean rate and regularity of heating;

d) Deviation from the specification for the preparation of the sample in respect of maximum particle size, or for

the pencil in respect of its length after tamping.
5 Apparatus
5.1 Apparatus for preparing the coal pencil
5.1.1 Mould, polished internally, with accessories; see Figure B.1.
5.1.2 Gauge.
5.1.3 Ram, of which Figure B.2 shows an example.
5.1.4 Press, of which Figure B.3 shows an example.
5.2 Dilatometer and accessories
5.2.1 Dilatometer tubes and pistons, see Figure B.4.
5.3 Other apparatus

5.3.1 Electric furnace, example shown in Figure B.5, consisting of a block of metal resistant to

oxidation and of sufficiently high melting point. A suggested material is aluminium bronze. The metal

block is pierced by at least two holes of 15 mm diameter by 350 mm deep to take the dilatometer

tubes and one hole 320 mm deep to take a temperature-measuring device, which intends to keep the

thermojunction of the thermocouple in the middle position of the inserted coal
...

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