Hard coal -- Determination of total moisture

ISO 589:2008 describes two methods for determination of the total moisture content of hard coals, a two-stage method and a single-stage method. For either method there is a choice between drying in air and drying in a nitrogen atmosphere. Depending on the coal rank, there may be systematic differences between the results obtained by drying in the different atmospheres on subsamples of a sample. Drying in a nitrogen atmosphere is suitable for all hard coals, while drying in air is only suitable for hard coals not susceptible to oxidation.

Houille -- Détermination de l'humidité totale

General Information

Status
Published
Publication Date
27-Oct-2008
Current Stage
6060 - International Standard published
Start Date
09-Oct-2008
Completion Date
28-Oct-2008
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INTERNATIONAL ISO
STANDARD 589
Fourth edition
2008-11-01
Hard coal — Determination of total
moisture
Houille — Détermination de l'humidité totale
Reference number
ISO 589:2008(E)
ISO 2008
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ISO 589:2008(E)
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ii © ISO 2008 – All rights reserved
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ISO 589:2008(E)
Contents Page

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

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

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

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

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

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

5 Reagent.................................................................................................................................................. 2

6 Apparatus .............................................................................................................................................. 3

7 Sample ................................................................................................................................................... 3

8 Procedure .............................................................................................................................................. 4

9 Precision................................................................................................................................................ 7

10 Test report ............................................................................................................................................. 8

Bibliography ....................................................................................................................................................... 9

© ISO 2008 – All rights reserved iii
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ISO 589:2008(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 589 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 5, Methods

of analysis.

This fourth edition cancels and replaces the third edition (ISO 589:2003), which has been technically revised.

iv © ISO 2008 – All rights reserved
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ISO 589:2008(E)
Introduction
Moisture is an important parameter in respect of coal quality.

The moisture content of coal is not an absolute value and conditions for its determination have to be

standardized. It is expected that the results given by the different methods specified here should be

comparable within the limits of the tolerance quoted.

It is always necessary that the determination of the total moisture content of hard coals be considered in close

connection with sampling. Therefore, this International Standard has been prepared in close relationship with

the ISO standards for mechanical sampling ISO 13909 (all parts) and manual sampling ISO 18283.

A major problem with the preparation of test samples for the determination of moisture is the risk of bias due

to inadvertent loss of moisture. This is dependent on the tightness of the sealing of sampling containers, the

level of moisture content in the sample, the ambient conditions, the type of coal and the reduction and division

procedures used. This is described in detail in ISO 13909-4 or ISO 18283.

Depending on the mass, the nominal top size and the facilities available where samples are taken, it is

possible to dry the sample directly after sampling (air-drying), then to reduce the particle size and prepare a

test sample for determination of moisture in the air-dried sample. Alternatively, the whole sample may be

transported to the laboratory and the total moisture determined.
© ISO 2008 – All rights reserved v
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INTERNATIONAL STANDARD ISO 589:2008(E)
Hard coal — Determination of total moisture
1 Scope

This International Standard describes two methods for determination of the total moisture content of hard

coals, a two-stage method and a single-stage method. For either method there is a choice between drying in

air and drying in a nitrogen atmosphere. Depending on the coal rank, there may be systematic differences

between the results obtained by drying in the different atmospheres on subsamples of the same sample.

Drying in a nitrogen atmosphere is suitable for all hard coals, while drying in air is only suitable for hard coals

not susceptible to oxidation.

NOTE The term “not susceptible to oxidation” cannot be defined easily. Usually, high-rank coals such as anthracites

are not oxidized under the conditions described in this International Standard. For all other types of coal, this has to be

verified by experiments.
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 1213-2, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and analysis

ISO 11722, Solid mineral fuels — Hard Coal — Determination of moisture in the general analysis test sample

by drying in nitrogen

ISO 13909-1, Hard coal and coke — Mechanical sampling — Part 1: General introduction

ISO 13909-2, Hard coal and coke — Mechanical sampling — Part 2: Coal — Sampling from moving streams

ISO 13909-3, Hard coal and coke — Mechanical sampling — Part 3: Coal — Sampling from stationary lots

ISO 13909-4:2001, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test

samples
ISO 18283:2006, Hard coal and coke — Manual sampling
3 Terms and definitions

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

© ISO 2008 – All rights reserved 1
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ISO 589:2008(E)
4 Principle
4.1 Method A — Two-stage methods
4.1.1 Method A 1 — Drying under nitrogen in second stage

The sample is dried in air at ambient temperatures or at elevated temperatures not exceeding 40 °C (first or

free-moisture stage) and the loss in mass recorded. The air-dried sample is crushed to 2,8 mm nominal top

size and subsamples are dried at 105 °C to 110 °C in a nitrogen-flushed oven (second or residual moisture

stage).
NOTE Residual moisture is often called moisture in the air-dried sample.

Provided that the result obtained for the determination of moisture in the analysis sample in accordance with

ISO 11722 can be shown to give the same result as that for the second-stage moisture determination, the

former may be used.
The moisture is calculated from the loss in mass at each of the two stages.
4.1.2 Method A 2 — Drying in air

The sample is dried in air at ambient temperatures or at elevated temperatures not exceeding 40 °C (first or

free-moisture stage) and the loss in mass recorded. The air-dried sample is crushed to 2,8 mm nominal top

size and subsamples are dried in air at 105 °C to 110 °C (second or residual moisture stage).

The moisture is calculated from the loss in mass at each of the two stages.
NOTE This method is suitable only for hard coals not susceptible to oxidation.
4.2 Method B — Single-stage methods
4.2.1 Method B 1 — Drying under nitrogen

The sample is crushed to a nominal top size of either 11,2 mm or, alternatively, 10 mm. A subsample is dried

in a nitrogen-flushed oven at a temperature of 105 °C to 110 °C. The moisture is calculated from the loss in

mass.
4.2.2 Method B 2 — Drying in air

The sample is crushed to a nominal top size of either 11,2 mm or, alternatively, 10 mm. A subsample is dried

in air at a temperature of 105 °C to 110 °C. The moisture is calculated from the loss in mass.

NOTE This method is suitable only for hard coals not susceptible to oxidation.
5 Reagent
Nitrogen, moisture-free, having an oxygen content of less than 30 µl/l.

NOTE Commercially available nitrogen with a water content of less than 5 µl/l does not require further drying.

2 © ISO 2008 – All rights reserved
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ISO 589:2008(E)
6 Apparatus
6.1 Method A

6.1.1 Oven, for first-stage moisture determination, capable of being controlled at a temperature of 30 °C to

40 °C, with a sufficiently rapid rate of atmosphere change (e.g. 5 times per hour). The air velocity shall be

such that the sample particles are not dislodged from their tray.

6.1.2 Nitrogen-flushed oven, for second-stage moisture determination, capable of being controlled at a

temperature of 105 °C to 110 °C, with the additional provision for passing a current of dry nitrogen through it

at a flow rate about 15 times the oven volume per hour. The gas velocity shall be such that the sample

particles are not dislodged from their dish.

6.1.3 Oven, for second-stage moisture determination, capable of being controlled at a temperature of

105 °C to 110 °C, with a sufficiently rapid rate of atmosphere change (e.g. 5 times per hour). The air velocity

shall be such that the sample particles are not dislodged from their dish.
6.2 M
...

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