ISO 609:2025
(Main)Coal and coke — Determination of carbon and hydrogen — High temperature combustion method
Coal and coke — Determination of carbon and hydrogen — High temperature combustion method
This document specifies a method of determining the total carbon and the total hydrogen in coal and coke by a high temperature combustion method.
Charbon et coke — Dosage du carbone et de l'hydrogène — Méthode par combustion à haute température
General Information
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Standards Content (Sample)
International
Standard
ISO 609
Third edition
Coal and coke — Determination
2025-05
of carbon and hydrogen — High
temperature combustion method
Charbon et coke — Dosage du carbone et de l'hydrogène —
Méthode par combustion à haute température
Reference number
© ISO 2025
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ii
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagents and materials . 2
6 Apparatus . 2
7 Preparation of the apparatus . 7
7.1 Preparation of the combustion tube .7
7.2 Location of the silver gauze roll .7
7.3 Conditioning the absorption train .8
8 Preparation of test sample . 9
9 Procedure . 9
9.1 Initial operations .9
9.2 Combustion of the test portion .9
9.3 Completion .9
10 Blank test .10
11 Expression of results . 10
11.1 Total carbon .10
11.2 Organic carbon .11
11.3 Total hydrogen .11
11.4 Total hydrogen mass fraction, less that present as moisture .11
11.5 Additional information.11
12 Precision .12
12.1 Repeatability limit . 12
12.2 Reproducibility limit . 12
13 Test report .12
Annex A (informative) Derivation of factors used in calculations .13
Bibliography .15
iii
Foreword
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This document was prepared by Technical Committee ISO/TC 27, Coal and coke, Subcommittee SC 5, Methods
of analysis.
This third edition cancels and replaces the second edition (ISO 609:1996), which has been technically
revised. It also incorporates the Technical Corrigendum ISO 609:1996/Cor. 1:1996.
The main changes are as follows:
— the normative references have been updated;
— Clause 3 has been added and subsequent clauses have been renumbered;
— Figures 1, 2, 3 and 4 have been modified to add keys;
— Clause 9 has been revised;
— Annex A has been revised.
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
Introduction
ISO 625 gives an alternative method to the one specified in this document.
v
International Standard ISO 609:2025(en)
Coal and coke — Determination of carbon and hydrogen —
High temperature combustion method
1 Scope
This document specifies a method of determining the total carbon and the total hydrogen in coal and coke
by a high temperature combustion method.
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 687, Coke — Determination of moisture in the general analysis test sample
ISO 925, Solid mineral fuels — Determination of carbonate carbon content — Gravimetric method
ISO 5068-2, Brown coals and lignites — Determination of moisture — Part 2: Indirect gravimetric method for
moisture in the analysis sample
ISO 11722, Solid mineral fuels — Hard coal — Determination of moisture in the general analysis test sample by
drying in nitrogen
ISO 13909-4, Coal and coke — Mechanical sampling — Part 4: Preparation of test samples of coal
ISO 13909-6, Coal and coke — Mechanical sampling — Part 6: Preparation of test samples of coke
ISO 18283, Coal and coke — Manual sampling
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminology databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at https:// www .iso .org/ obp
— IEC Electropedia: available at https:// www .electropedia .org/
4 Principle
A known mass of coal or coke is burnt in a stream of oxygen, at a temperature of 1 350 °C, in a tube impervious
to gases. All the hydrogen is converted to water and all the carbon to carbon dioxide. These products are
absorbed by suitable reagents and determined gravimetrically. The chlorine and oxides of sulfur which are
formed are retained by a silver gauze roll at the outlet end of the tube.
The results include the carbon in the carbonates and the hydrogen combined in the moisture and in the water
of constitution of silicates. A determination of moisture is carried out at the same time, and an appropriate
correction is applied to the hydrogen value obtained by combustion. A determination of carbon dioxide may
also be made and the total carbon value corrected for the presence of mineral carbonates.
5 Reagents and materials
WARNING — Care shall be exercised when handling reagents, many of which are toxic and corrosive.
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only
distilled water or water of equivalent purity.
5.1 Magnesium perchlorate, anhydrous, less than 1,2 mm in size and preferably within the size range
1,2 mm to 0,7 mm.
WARNING — Determine any local regulations when disposing of exhausted magnesium perchlorate
prior to use. Regeneration of magnesium perchlorate shall not be attempted, owing to the risk of
explosion.
5.2 Sodium hydroxide on an inert base, preferably of a coarse grading, for example 3,0 mm to 1,5 mm,
but not finer than the grading 1,2 mm to 0,7 mm, and preferably of the self-indicating type.
5.3 Aluminium oxide (alumina), finely divided, approximately 0,1 mm in size.
5.4 Sodium tetraborate, standard volumetric solution, c(Na B O ) = 0,025 mol/l.
2 4 7
Dissolve 9,534 2 g of sodium tetraborate decahydrate in water and dilute to 1 litre. Mix thoroughly.
5.5 Hydrogen peroxide, mass fraction approximately 30 %.
5.6 Pure silver gauze, of mesh approximately 1 mm, made of wire approximately 0,3 mm in diameter.
5.7 Oxygen, hydrogen-free, preferably prepared from liquid air and not by electrolysis. Electrolytically
prepared oxygen shall be passed over red-hot copper oxide before use to remove any trace of hydrogen.
5.8 Mixed indicator solution
5.8.1 Solution A
Dissolve 0,125 g of 2-(4-dimethylaminophenylaz
...
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