ISO/TS 13605:2012
(Main)Solid mineral fuels — Major and minor elements in hard coal ash and coke ash — Wavelength dispersive X-ray fluorescence spectrometric method
Solid mineral fuels — Major and minor elements in hard coal ash and coke ash — Wavelength dispersive X-ray fluorescence spectrometric method
ISO/TS 13605:2012 sets out a wavelength dispersive X-ray fluorescence procedure for the determination of silicon, aluminium, iron, calcium, magnesium, sodium, potassium, titanium, manganese, phosphorus and sulfur. The method is applicable to coal ashes, coke ashes and boiler ashes having components within the concentration ranges specified in ISO/TS 13605:2012.
Combustibles minéraux solides — Éléments en minorité et en majorité dans les cendres de houille et de coke — Méthode spectrométrique par fluorescence aux rayons X à une longueur d'onde dispersive
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Standards Content (Sample)
TECHNICAL ISO/TS
SPECIFICATION 13605
First edition
2012-05-15
Solid mineral fuels — Major and minor
elements in hard coal ash and coke
ash — Wavelength dispersive X-ray
fluorescence spectrometric method
Combustibles minéraux solides — Éléments en minorité et en majorité
dans les cendres de houille et de coke — Méthode spectrométrique par
fluorescence aux rayons X à une longueur d’onde dispersive
Reference number
ISO/TS 13605:2012(E)
©
ISO 2012
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ISO/TS 13605:2012(E)
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ii © ISO 2012 – All rights reserved
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ISO/TS 13605:2012(E)
Contents Page
Foreword .iv
1 Scope . 1
2 Normative references . 2
3 Terms and definitions . 2
4 Principle . 2
5 Reagents . 2
5.1 General . 2
5.2 Flux and heavy absorber . 2
6 Apparatus . 2
6.1 General . 2
6.2 Crucible . 3
6.3 Mould . 3
6.4 Crucible tongs . 3
6.5 Desiccator . 3
6.6 Sample holders . 3
6.7 X-ray fluorescence spectrometer . 3
7 Sample . 4
7.1 Coal and coke ash prepared in the laboratory . 4
7.2 Coal and coke ash . 4
8 Procedure . 4
8.1 Number of determinations . 4
8.2 Test portion . 4
8.3 Check test . 4
8.4 Calibration . 4
8.5 Preparation of the fused discs . 5
8.6 XRF measurement . 6
9 Calculation . 7
9.1 General . 7
9.2 Correction of instrumental drift . 7
9.3 Correction for dead time losses . 7
9.4 Matrix corrections . 8
10 Reporting results . 8
11 Precision . 8
12 Test report . 9
Annex A (normative) Acceptance of analytical results for laboratory method .10
Annex B (informative) Reagents suitable for the preparation of synthetic calibration standards .12
Annex C (normative) Standard deviation of glass disc preparation .13
Bibliography .15
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ISO/TS 13605:2012(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.
In other circumstances, particularly when there is an urgent market requirement for such documents, a technical
committee may decide to publish other types of document:
— an ISO Publicly Available Specification (ISO/PAS) represents an agreement between technical experts in
an ISO working group and is accepted for publication if it is approved by more than 50 % of the members
of the parent committee casting a vote;
— an ISO Technical Specification (ISO/TS) represents an agreement between the members of a technical
committee and is accepted for publication if it is approved by 2/3 of the members of the committee
casting a vote.
An ISO/PAS or ISO/TS is reviewed after three years in order to decide whether it will be confirmed for a further
three years, revised to become an International Standard, or withdrawn. If the ISO/PAS or ISO/TS is confirmed,
it is reviewed again after a further three years, at which time it must either be transformed into an International
Standard or be withdrawn.
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/TS 13605 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 5,
Methods of analysis.
iv © ISO 2012 – All rights reserved
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TECHNICAL SPECIFICATION ISO/TS 13605:2012(E)
Solid mineral fuels — Major and minor elements in hard coal
ash and coke ash — Wavelength dispersive X-ray fluorescence
spectrometric method
WARNING — Use of this Technical Specification can involve hazardous materials, operations and
equipment. This Technical Specification does not purport to address all of the safety problems associated
with its use. It is the responsibility of the user of this Technical Specification to establish appropriate
safety and health practices and determine the applicability of regulatory limitations prior to use.
1 Scope
This Technical Specification sets out a wavelength dispersive X-ray fluorescence (XRF) procedure for the
determination of silicon, aluminium, iron, calcium, magnesium, sodium, potassium, titanium, manganese,
phosphorus and sulfur.
The method is applicable to coal ashes, coke ashes and boiler ashes having components within the concentration
ranges specified in Table 1.
Table 1 — Ranges of application of the method
Concentration range
Oxide
%
SiO 5–100
2
Al O 5–80
2 3
Fe O 0,1–25
2 3
CaO 0,05–25
MgO 0,05–25
Na O 0,05–5
2
K O 0,05–5
2
TiO 0,05–5
2
Mn O 0,005–5
3 4
P O 0,01–5
2 5
SO 0,05–10
3
NOTE 1 Additional analytes may be included in the method,
provided that appropriate validation using reference materials is
carried out.
NOTE 2 The precision statistics can be determined using
suitable reference materials.
NOTE 3 The method described in this Technical Specification
has been tested for the following additional analytes:
BaO (0,01 % to 1 %); SrO (0,01 % to 1 %) and ZnO (0,005 % to 1 %).
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ISO/TS 13605:2012(E)
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 1171, Solid mineral fuels — Determination of ash
ISO 1213-2, Solid mineral fuels — Vocabulary — Part 2: Terms relating to sampling, testing and analysis
ISO 13909-4, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples
ISO 13909-6, Hard coal and coke — Mechanical sampling — Part 6: Coke — Preparation of test samples
3 Terms and definitions
For the purposes of this document, the terms and definitions given in ISO 1213-2 apply.
4 Principle
The specimen on which X-ray fluorescence measurements are made is prepared by incorporating the test
portion of the sample, via fusion, into a borate glass disc using a casting or press-quenching procedure. By
using such a specimen, particle size effects are eliminated.
Calibration is carried out using pure chemicals and/or reference standards, and by making matrix corrections
for inter-element effects.
It is expected that laboratories using this Technical Specification have experience in analysing coal ashes of
certain compositions and that they employ calibrations that cover these compositions.
5 Reagents
5.1 General
Unless otherwise specified, all reagents shall be of analytical grade and only distilled water or water of
equivalent purity shall be used.
5.2 Flux and heavy absorber
Borate fluxes of differing compositions have been found suitable for preparing glass discs from coal/coke
ash samples. These fluxes are based on mixtures of one or more of the following: lithium tetraborate, lithium
metaborate and lanthanum oxide. Flux may be purchased commercially or prepared by fusion of a mixture of
individual reagents.
NOTE The levels of contamination in the flux should be checked. Because levels of contamination may vary from
batch to batch, the same batch of flux should be used for all specimens (synthetic standards, external standards and
unknowns). When using a fresh batch of flux, reference material specimens should be prepared to determine whether
adjustments to the calibration are required.
6 Apparatus
6.1 General
All apparatus shall be constructed from materials that are thermally stable and chemically inert under the
conditions of the procedure.
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ISO/TS 13605:2012(E)
6.2 Crucible
The crucible shall be made from a non-wetting platinum alloy. The crucible shall have sufficient capacity to hold
the flux and sample required for fusion. Normally, 15 ml crucibles are adequate for discs of 32 mm in diameter,
and 25 ml crucibles for discs of 40 mm in diameter.
NOTE Either platinum/gold or platinum/gold/rhodium alloys are suitable.
Because the crucible and lid (if used) are to be used for fusion work, the normal precautions associated with
the care of hot platinum ware should be observed. It is necessary, therefore, to have suitable tongs and a
surface on which to rest the crucible. The hot crucible can be rested on a refractory surface, which shall be
kept very clean.
Although the crucible is fabricated from an alloy that is not wetted by the glass, for the greatest precision, the
crucible should be cleaned between each fusion. The use of citric acid (mass concentration of 20 %), dilute
hydrochloric acid (volume fraction of 10 %–50 %) or dilute chlorine-free nitric acid (volume fraction of 10 %)
have proven to be suitable for crucible cleaning. The use of an ultrasonic bath will accelerate this process. An
alternative method of cleaning is to fuse several grams of flux in the crucible, moving the melt around so as to
clean the entire inner surface. The molten flux is poured from the crucible. If a droplet adheres to the crucible,
this can easily be flaked off when the crucible is cold.
6.3 Mould
The mould shall be made from non-wetting material. For example, platinum alloy is commonly used for casting
discs, and aluminium or graphite is suitable for press quenching.
In the casting technique, the bottom of the disc is the analytical surface. The mould should therefore be flat
and sufficiently thick that it is not easily deformed. Casting moulds should be checked regularly for flatness and
should be polished regularly, to ensure that the disc releases from the mould. Platens for press-quenching are
constructed so that the depth gradually increases from the perimeter to the centre. The analytical surface for
press-quenched discs is the surface which contacts the plunger head. Care should be taken not to choose the
platen side for intensity measurements.
6.4 Crucible tongs
The crucible tongs shall be platinum-tipped or stainless steel or titanium.
NOTE Stainless steel or titanium tongs are a suitable alternative to platinum-tipped tongs.
6.5 Desiccator
The desiccator shall contain freshly regenerated, self-indicating silica gel.
6.6 Sample holders
Sample holders shall be used for specimen presentation.
6.7 X-ray fluorescence spectrometer
Any conventional wavelength dispersive (sequential, simultaneous, or combination simultaneous/sequential)
vacuum path X-ray fluorescence spectrometer may be used, provided that it conforms to precision requirements
6
at the 0,1 % (10 counts) precision level.
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ISO/TS 13605:2012(E)
7 Sample
7.1 Coal and coke ash prepared in the laboratory
The coal or coke sample shall be the analysis sample, prepared to a nominal top size of 212 µm. Sample
preparation shall be in accordance with ISO 13909-4 for coal samples or ISO 13909-6 for coke samples.
The sample shall then be ashed using the procedure specified in ISO 1171.
7.2 Coal and coke ash
Coal or coke ash received at the laboratory shall be heated at 815 °C for 15 min and cooled in a desiccator over
freshly regenerated, self-indicating silica gel immediately prior to weighing for analysis.
Boiler ash received at the laboratory should be ground to a nominal top size of 63 µm and dried at 105 °C
for 1 h, then stored in a desiccator over freshly regenerated, self-indicating silica gel.
8 Procedure
8.1 Number of determinations
Discs shall be prepared and analysed as single determinations and a reference material shall be prepared and
analysed at the beginning and end of each batch of samples containing a maximum of 25 samples.
8.2 Test portion
The mass of the test portion shall be appropriate for the mould size and sample flux ratio chosen.
NOTE 1 Typically, sample-to-flux ratios are in the range 1:5 to 1:10.
NOTE 2 Typical total mass (sample plus flux) is 4 g for a 32 mm diameter and 7,5 g for a 40 mm diameter mould.
8.3 Check test
At least one reference material of similar composition to the samples being analysed shall be included with
each batch of test samples and shall be analysed in parallel with, and under the same conditions as, the test
samples. The results for the batch of samples shall be rejected if the results for the reference material fail to
meet the acceptance criteria detailed in Annex A.
8.4 Calibration
Calibra
...
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