ISO 7404-5:2009
(Main)Methods for the petrographic analysis of coals — Part 5: Method of determining microscopically the reflectance of vitrinite
Methods for the petrographic analysis of coals — Part 5: Method of determining microscopically the reflectance of vitrinite
ISO 7404-5:2009 specifies the methods for determining the reflectance of vitrinite of coals microcopically on the polished surfaces, immersed in oil. The methods are applicable to coals from single seams or coal blends covering the whole range of low-, medium- and high-rank coal. Vitrinite reflectance measurements can be used to characterize the components within blends. Measures can be taken to correct for the vitrinite percentage within each of the components of the blend or to determine the proportion of components in a blend, particularly when the components have dissimilar vitrinite contents. This method necessitates the identification of vitrinite by the analyst. Reflectance measurements on vitrinite obtained by interpreting the results from an automated system, are outside the scope of ISO 7404-5:2009.
Méthodes d'analyse pétrographique des charbons — Partie 5: Détermination au microscope du pouvoir réflecteur de la vitrinite
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Standards Content (Sample)
INTERNATIONAL ISO
STANDARD 7404-5
Third edition
2009-10-01
Methods for the petrographic analysis of
coals —
Part 5:
Method of determining microscopically
the reflectance of vitrinite
Méthodes d'analyse pétrographique des charbons —
Partie 5: Détermination au microscope du pouvoir réflecteur de la
vitrinite
Reference number
©
ISO 2009
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ii © ISO 2009 – All rights reserved
Contents Page
Foreword .iv
Introduction.v
1 Scope.1
2 Normative references.1
3 Definitions .1
4 Principle .1
5 Reagents and materials .2
6 Apparatus.3
7 Preparation of coal sample .7
8 Procedure.7
9 Reporting of results .10
10 Precision .12
11 Test report.13
Bibliography.14
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 7404-5 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels.
This third edition cancels and replaces the second edition (ISO 7404-5:1994), which has been technically
revised.
ISO 7404 consists of the following parts, under the general title Methods for the petrographic analysis of coals:
1)
⎯ Part 1: Vocabulary
⎯ Part 2: Methods of preparing coal samples
⎯ Part 3: Method of determining maceral group composition
1)
⎯ Part 4: Method of determining microlithotype, carbominerite and minerite composition
⎯ Part 5: Method of determining microscopically the reflectance of vitrinite
1) Parts 1 and 4 of this International Standard will be available under the original title, Methods for the petrographic
analysis of bituminous coal and anthracite, until the revisions of these documents have reached the stage at which they
are publicly available.
iv © ISO 2009 – All rights reserved
Introduction
Petrographic analyses have been recognized internationally as important in the context of the genesis, vertical
and lateral variation, continuity, metamorphism and usage of coal. The International Committee for Coal and
Organic Petrology (ICCP) has made recommendations concerning nomenclature and analytical methods and
has published a comprehensive handbook that is continuously updated. The text of this part of ISO 7404
agrees substantially with the text of the handbook and incorporates many useful comments made by members
of the ICCP and by member bodies of ISO/TC 27, Solid mineral fuels.
Petrographic analyses of single seam coals provide information about the rank, the maceral and
microlithotype compositions and the distribution of minerals in the coal. The reflectance of vitrinite is a useful
measure of coal rank and can provide information on the distribution of coals of different rank in a coal blend.
Together with a maceral group analysis, it provides information about some important chemical and
technological properties of the coal and the coal blend. The reflectance of vitrinite has various other
applications, such as the characterization of bulk samples and cargoes. For coal blends, the measurement of
the vitrinite reflectance profile can permit the identification of the component coals and permit the estimation of
the relative abundance of the component coals within the blend.
ISO 7404 (all parts) is concerned with the methods of petrographic analysis currently employed in
characterizing coal in the context of their technological use.
[7]
The method of determining the reflectance of vitrinite is applicable for low-, medium- and high-rank coals .
The properties of a given coal are determined by the proportions and associations of the macerals and
[3]
minerals present (see ISO 7404-3 ) and by the rank of the coal and thus its type, grade and rank. The
reflectance of the vitrinite in the coal can be used as an indicator of rank, independent of the petrographic
composition. Vitrinite reflectance increases progressively with rank.
The reflectances of the macerals of the vitrinite group can vary significantly in a single coal seam and
therefore the value of the reflectance obtained depends also on the choice of the macerals used for
measurement. Reflectance measurements are made on one or more of the macerals of vitrinite and, in
reporting the results, it is necessary to specify the macerals on which the measurement were made and the
proportions of the overall value contributed by each of the macerals measured. Consequently, a vital step in
the measurement of vitrinite reflectance is the identification of vitrinite and its various macerals or maceral
[1]
varieties. For this purpose, reference can be made to ISO 7404-1 and the ICCP handbook.
[6]
For rank determination of single-seam coals, normally the reflectance of collotelinite (eu-ulminite in lignites,
[6]
the equivalent of low-rank B and C ) is determined. In cases where collotelinite (or in low-rank coals,
eu-ulminite) is not present in sufficient amounts, reflectance analysis on other vitrinite macerals is performed.
Reflectance analysis on various vitrinite macerals can also be applied for technological purposes and to coal
blends; see 8.3.1. The reflectance value obtained also depends on whether maximum or random reflectance
measurements are made, so it is necessary to specify the type of measurement. All of these analysis
procedures are applicable to single-coal seams or to blends providing that adequate (see 8.3.1) reflectance
measurements are made in compliance with an unbiased sampling procedure on a representative sample.
An accreditation programme for vitrinite reflectance analysis of single-seam coals (SCAP) is run regularly by
the ICCP for accrediting petrologists.
NOTE As this edition of ISO 7404 covers coals of all rank, the term “vitrinite” as used in this part of ISO 7404
includes vitrinite as well as huminite. Reference can be made to ISO 7404-1 for details. The equivalent to collotelinite in
lignites is ulminite B. Reflectance measurement on lignites is performed on huminite.
INTERNATIONAL STANDARD ISO 7404-5:2009(E)
Methods for the petrographic analysis of coals —
Part 5:
Method of determining microscopically the reflectance of
vitrinite
1 Scope
This part of ISO 7404 specifies the methods for determining the reflectance of vitrinite of coals microscopically
on the polished surfaces, immersed in oil. The methods are applicable to coals from single seams or coal
blends covering the whole range of low-, medium- and high-rank coal.
Vitrinite reflectance measurements can be used to characterize the components within blends. Measures can
be taken to correct for the vitrinite percentage within each of the components of the blend or to determine the
proportion of components in a blend, particularly when the components have dissimilar vitrinite contents. This
method necessitates the identification of vitrinite by the analyst.
Reflectance measurements on vitrinite obtained by interpreting the results from an automated system, are
outside the scope of this part of ISO 7404.
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 7404-1, Methods for the petrographic analysis of bituminous coal and anthracite — Part 1: Vocabulary
ISO 7404-2, Methods for the petrographic analysis of coals — Part 2: Methods of preparing coal samples
3 Definitions
For the purposes of this document, the definitions given in ISO 7404-1 apply.
4 Principle
The intensity of light reflected at near-normal incidence from a specified area of well polished vitrinite under oil
immersion, measured at 546 nm using a photomultiplier (or similar device), is compared with the intensity of
light reflected under identical conditions from a number of standards of known reflectance. Different vitrinite
particles within a single-coal seam invariably differ slightly from one another in optical properties. Therefore,
an adequate number (see 8.3.1) of readings on different particles is taken to ensure that the results are
representative of the coal or coal blend.
5 Reagents and materials
5.1 Immersion oil, non-drying, non-corrosive type, with a refractive index of 1,518 0 ± 0,000 4 at 23 °C and
a wavelength of 546 nm.
Oil from a bottle opened more than one year ago should not be used.
In attempts to produce oils that are chemically and physically stable, toxic compounds such as polychlorinated
bi-phenyls were used in some older products. Some more recent oils have been associated with allergies. The
composition of the oil should, therefore, be checked to ensure that no toxic or other undesirable properties are
associated with it.
5.2 Calibration standards
5.2.1 Reflectance standards, consisting of polished surfaces of materials that
a) are isotropic (or basal sections of uniaxial minerals);
b) are durable and resistant to corrosion;
c) have a reflectance that is stable over a long period;
d) are free from inclusions, grain boundaries, discontinuities, internal flaws and fractures;
e) have negligibly low absorptance.
To avoid significant amounts of light other than that reflected from the top surface returning to the objective,
the body of the standard shall be either thicker than 5 mm or wedge-shaped. The lower surface shall be matt if
it makes an angle of less than 10° with the upper polished surface. The sides shall be shielded from external
light. The reflectance of the standards shall be of an order similar to that of the coal being measured. Use at
least two such standards with well spaced reflectances. If a coal with a reflectance greater than 2,0 % is being
measured, use one or more additional standards with reflectance greater than 2,0 %.
Table 1 gives approximate mean values for reflectance standards o
...
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