ISO 975:2021

INTERNATIONAL ISO
STANDARD 975
Fifth edition
2021-12
Brown coals and lignites —
Determination of yield of benzene-
soluble extract — Semi-automatic
method
Charbons bruns et lignites — Détermination du rendement en extrait
de benzène soluble — Méthode semi-automatique
Reference number
ISO 975:2021(E)
© ISO 2021

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ISO 975:2021(E)
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© ISO 2021
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ISO 975:2021(E)
Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Principle . 1
5 Reagent . 1
6 Apparatus . 1
7 Preparation of sample . 2
8 Preliminary adjustment of instrument . 2
8.1 Adjustment of the extraction temperature . 2
8.2 Selection of periods of extraction, rinsing and evaporation . 2
8.3 Procedure . 3
9 Calculation and expression of results . 3
10 Precision . 4
10.1 Repeatability limit . 4
10.2 Reproducibility limit . 4
11 Test report . 4
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ISO 975:2021(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards
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www.iso.org/iso/foreword.html.
This document was prepared by Technical Committee ISO/TC 27, Coal and coke, Subcommittee SC 5,
Methods of analysis.
This fifth edition cancels and replaces the fourth edition (ISO 975:2013), of which it constitutes a minor
revision. The changes compared to the previous edition are as follows:
— referenced documents have been updated;
— terms and definitions have been added;
— sample has been added;
— calculation and expression of results have been amended;
— precision has been amended;
— test report has been amended.
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
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ISO 975:2021(E)
Introduction
The determination of yield of benzene-soluble extract is carried out using a semi-automatic instrument;
a system combining extraction, rinsing and evaporation. As long as the sample is put in the extraction
chamber of the instrument, the test can be done automatically.
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INTERNATIONAL STANDARD ISO 975:2021(E)
Brown coals and lignites — Determination of yield of
benzene-soluble extract — Semi-automatic method
1 Scope
This document specifies a semi-automatic method for determination of the yield of benzene-soluble
extract in brown coals and lignites.
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 5068-2, Brown coals and lignites — Determination of moisture content — Part 2: Indirect gravimetric
method for moisture in the analysis sample
ISO 13909-4, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples
ISO 18283, Coal and coke — Manual sampling
3 Terms and definitions
No terms and definitions are listed in this document.
ISO and IEC maintain terminological 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
...