ISO 975:2000

SLOVENSKI STANDARD
SIST ISO 975:2002
01-junij-2002
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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
Ta slovenski standard je istoveten z: ISO 975:2000
ICS:
73.040 Premogi Coals
SIST ISO 975:2002 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 975:2002

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SIST ISO 975:2002
INTERNATIONAL ISO
STANDARD 975
Third edition
2000-10-01
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 975:2000(E)
©
ISO 2000

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SIST ISO 975:2002
ISO 975:2000(E)
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ii © ISO 2000 – All rights reserved

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SIST ISO 975:2002
ISO 975:2000(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
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Commission (IEC) on all matters of electrotechnical standardization.
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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 International Standard may be the subject of
patent rights. ISO shall not be held responsible for identifying any or all such patent rights.
International Standard ISO 975 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels,
Subcommittee SC 5, Methods of analysis.
This third edition cancels and replaces the second edition (ISO 975:1985), which has been technically revised.
© ISO 2000 – All rights reserved iii

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SIST ISO 975:2002
ISO 975:2000(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.
iv © ISO 2000 – All rights reserved

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SIST ISO 975:2002
INTERNATIONAL STANDARD ISO 975:2000(E)
Brown coals and lignites — Determination of yield of benzene-
soluble extract — Semi-automatic method
1 Scope
This International Standard specifies a semi-automatic method for determination of the yield of benzene-soluble
extract in brown coals and lignites.
2 Normative reference
The following normative document contains provisions which, through reference in this text, constitute provisions of
this International Standard. For a dated reference, subsequent amendments to, or revisions of, the publication do
not apply. However, parties to agreements based on this International Standard are encouraged to investigate the
possibility of applying the most recent edition of the normative document indicated below. For an undated
reference, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain
registers of currently valid International Standards.
ISO 5068:1983, Brown coals and lignites — Determination of moisture content — Indirect gravimetric method.
3Principle
A test portion of the brown coal or lignite is extracted with benzene in a semi-automatic extraction instrument. The
solvent is then removed by evaporation and the soluble residue dried to constant mass. The percentage of
benzene-soluble extract is calculated from the mass of residue after drying and is reported on the dry basis.
4 Reagent
Benzene, of analytical reagent grade, � = 0,876 g/ml, distillation range 80 °Cto 81 °C. At least 95 % shall distil
20
within this range.
WARNING — Benzene is flammable and toxic by inhalation, ingestion or skin absorption.
The test must be carried out in a hood and the benzene must be recovered as completely as possible.
5 Apparatus
5.1 Semi-automatic extraction instrument, containing mainly two units: the continuous extraction-evaporation
device and the controller. The continuous extraction-evaporation device consists of a 100 ml conical flask, an
extraction chamber and a condenser. The extraction chamber is 180 mm long and 30 mm in internal diameter and
is provided with a water jacket through which the bath water is circulated in order to maintain the extraction
temperature around the extraction chamber.
5.2 Extraction thimble, 25 mm � 80 mm. Cellulose or other thimbles are purchased or made as follows.
© ISO 2000 – All rights reserved 1

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SIST ISO 975:2002
ISO 975:2000(E)
Cut filter paper into pieces of 75 mm � 75 mm and 25 mm � 25 mm. Moisten on
...