ISO 15237:2003

SLOVENSKI STANDARD
SIST ISO 15237:2005
01-november-2005
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Solid mineral fuels -- Determination of total mercury content of coal
Combustibles minéraux solides -- Dosage du mercure total dans le charbon
Ta slovenski standard je istoveten z: ISO 15237:2003
ICS:
73.040 Premogi Coals
SIST ISO 15237:2005 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 15237:2005

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SIST ISO 15237:2005


INTERNATIONAL ISO
STANDARD 15237
First edition
2003-12-01


Solid mineral fuels — Determination of
total mercury content of coal
Combustibles minéraux solides — Dosage du mercure total dans le
charbon




Reference number
ISO 15237:2003(E)
©
ISO 2003

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SIST ISO 15237:2005
ISO 15237:2003(E)
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ii © ISO 2003 — All rights reserved

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SIST ISO 15237:2005
ISO 15237:2003(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.
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 15237 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 5,
Methods of analysis.
© ISO 2003 — All rights reserved iii

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SIST ISO 15237:2005
ISO 15237:2003(E)
Introduction
Mercury occurs naturally in coal. It is an element that can be released during the combustion process.
The determination of the total mercury content of coal cannot be accomplished satisfactorily by traditional
ashing and digestion procedures because of the volatility of the element.
Quantitive recovery can be achieved by strict adherence to the procedure set out in this International Standard.
Instrumental methods for a more rapid determination of total mercury content are available. If such a method
is to be used, it is important to demonstrate that the method is free from bias, when compared to this
reference method and will give levels of repeatability and reproducibility which are the same, or better than,
those quoted for the reference method (see Clause 9).

iv © ISO 2003 — All rights reserved

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SIST ISO 15237:2005
INTERNATIONAL STANDARD ISO 15237:2003(E)

Solid mineral fuels — Determination of total mercury content of
coal
1 Scope
This International Standard specifies a procedure for the determination of the total mercury content of coal.
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 331, Coal — Determination of moisture in the analysis sample — Direct gravimetric method
ISO 1170, Coal and coke — Calculation of analyses to different bases
ISO 1928:1995, Solid mineral fuels — Determination of gross calorific value by the bomb calorimetric method,
and calculation of net calorific value
ISO 3696, Water for analytical laboratory use — Specifications and test methods
ISO 5068, Brown coals and lignites — Determination of moisture content — Indirect gravimetric method
ISO 5069-2, Brown coals and lignites — Principles of sampling — Part 2: Sample preparation for
determination of moisture content for general analysis
ISO 13909-2, Hard coal and coke — Mechanical sampling — Part 2: Coal — Sampling from moving streams
3 Principle
The sample is burned in an oxygen bomb, the mercury species formed during combustion being absorbed in
water. The mercury species present in the water are reduced by stannous chloride and quantified by
flameless cold vapour atomic absorption spectroscopy.
NOTE It is reported that lithium borohydride (LiBH ) and sodium borohydride (NaBH ) are satisfactory for the
4 4
reduction instead of stannous chloride; laboratories using these reductants should demonstrate that the performance is
equivalent to that using stannous chloride.
4 Reagents
WARNING — Care should be exercised when handling the reagents, many of which are toxic and
corrosive.
During the analysis, unless otherwise stated, use only reagents of recognized analytical grade.
© ISO 2003 — All rights reserved 1

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SIST ISO 15237:2005
ISO 15237:2003(E)
4.1 Water, conforming to Grade 1 of ISO 3696.
4.2 Oxygen, free from combustible matter and having a purity of at least 99,5 %.
4.3 Nitric acid solution, 10 % by volume, prepared by diluting 100 ml of concentrated nitric acid (relative
density 1,42) to 1 litre with water. The 10 % solution shall have a mercury content less than 0,1 µg/l.
4.4 Mercury standard stock solution, 1 000 µg/ml, prepared by dissolving 1,0 g of high purity mercury in
5 ml of 25 % (V/V) nitric acid solution and diluting to 1 000 ml.
NOTE 1 The mercury standard stock solution may also be prepared from commercially available certified mercury
solution.
NOTE 2 Other high purity (> 99,9 % ) mercury salts or oxides may be used with appropriate adjustment of the mass
taken.
4.5 Mercury standard solution, 0,1 µg/ml, prepared by diluting 5,0 ml of mercury standard stock solution
(4.4) to 500 ml with water and then diluting 10,0 ml of the intermediate solution to 1 litre with water.
This mercury standard solution should be prepared daily.
4.6 Potassium permanganate solution, 50 g/l, prepared by dissolving 5 g of potassium permanganate
(KMnO ) in water and diluting to 100 ml.
4
The mercury content of the potassium permanganate should be below 0,05 µg/g
4.7 Hydroxylammonium chloride solution, 15 g/l, prepared by dissolving 1,5 g of hydroxylammonium
chloride (HONH Cl) in water and diluting to 100 ml.
3
The mercury content of the hydroxylammonium chloride should be below 0,005 µg/g.
4.8 Reducing agent, stannous chloride solution, 100 g/l, prepared by dissolving 10 g of stannous
chloride dihydrate (SnCl⋅2H O) in 45 ml of concentrated hydrochloric acid solution (relative density 1,19) and
2 2
cautiously diluting to 100 ml with water.
The mercury content of the stannous chloride dihydrate should be below 0,01 µg/g.
NOTE See also note 1 to 9.2 regarding the use of flow injection techniques.
5 Apparatus
5.1 Balance
...