© ISO 2016 Solid mineral fuels — Determination of total mercury content of coal Combustibles minéraux solides — Dosage du mercure total dans le charbon INTERNATIONAL STANDARD ISO 15237 Second edition[.]
INTERNATIONAL STANDARD ISO 15237 Second edition 2016-11-15 Solid mineral fuels — Determination of total mercury content of coal Combustibles minéraux solides — Dosage du mercure total dans le charbon Reference number ISO 15237:2016(E) © ISO 2016 ISO 15237:2016(E) COPYRIGHT PROTECTED DOCUMENT © ISO 2016, Published in Switzerland All rights reserved Unless otherwise specified, no part o f this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission Permission can be requested from either ISO at the address below or ISO’s member body in the country o f the requester ISO copyright o ffice Ch de Blandonnet • CP 401 CH-1214 Vernier, Geneva, Switzerland Tel +41 22 749 01 11 Fax +41 22 749 09 47 copyright@iso.org www.iso.org ii © ISO 2016 – All rights reserved ISO 15237:2016(E) Page Contents Foreword iv Introduction v Scope Normative references Terms and definition Principle Reagents Apparatus Preparation of sample Oxygen bomb combustion procedure Preparation of test solution 8.1 8.2 General Combustion of coal 10 Atomic absorption analysis 11 Expression of results 10.1 Calibration 10.2 Analytical procedure 12 Precision 13 Test report 12.1 12.2 Repeatability limit Reproducibility critical di fference © ISO 2016 – All rights reserved iii ISO 15237:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies) The work o f 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 o f electrotechnical standardization The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part In particular the different approval criteria needed for the di fferent types o f ISO documents should be noted This document was dra fted in accordance with the editorial rules of the ISO/IEC Directives, Part (see www.iso.org/directives) Attention is drawn to the possibility that some o f the elements o f this document may be the subject o f patent rights ISO shall not be held responsible for identi fying any or all such patent rights Details o f any patent rights identified during the development o f the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents) Any trade name used in this document is in formation given for the convenience o f users and does not constitute an endorsement For an explanation on the meaning o f ISO specific terms and expressions related to formity assessment, as well as information about ISO’s adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html The committee responsible for this document is ISO/TC 27, Solid mineral fuels, Subcommittee SC 5, Methods of analysis This second edition cancels and replaces the first edition (ISO 15237:2003), which has been technically revised This document incorporates changes related to dated references and other minor items ollowing its systematic review f iv © ISO 2016 – All rights reserved ISO 15237:2016(E) Introduction M erc u r y o cc u rs natu l ly i n co a l I t i s an element th at c an b e rele as e d duri ng the combu s tion pro ce s s T he de term i nation o f the to ta l merc u r y content o f co a l c an no t b e accompl i she d s ati s fac tori ly b y trad itiona l as h i ng a nd d ige s tion pro ce du re s b e c au s e o f the volati l ity o f the element Qua ntitive re cover y c a n b e ach ieve d by s tric t ad herence to the pro ce du re s e t out i n th i s c ument I n s tru menta l me tho d s for a more rapid de term i nation o f to ta l merc u r y content are avai lable I f s uch a method is to be used, it is important to demonstrate that the method is free from bias, when compared f f or better than, those quoted for the reference method (see Clause 10) with th i s re erence me tho d and wi l l give level s o © ISO 2016 – All rights reserved rep e atabi l ity a nd repro ducibi l ity wh ich a re the s ame, v INTERNATIONAL STANDARD ISO 15237:2016(E) Solid mineral fuels — Determination of total mercury content of coal Scope T h i s c ument s p e c i fie s a pro ce dure T he for the de term i nation o f the to ta l merc ur y content o f co a l Normative references fol lowi ng c u ments are re ferre d to i n the tex t i n s uch a way th at s ome or a l l o f thei r content s titute s re qu i rements o f th i s c u ment For date d re ference s , on ly the e d ition cite d appl ie s For u ndate d re ference s , the late s t e d ition o f the re ference d c ument (i nclud i ng a ny amend ments) appl ie s ISO 1170, Coal and coke — Calculation of analyses to different bases ISO 1928, 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 — Specification and test methods ISO 5068-2, Brown coals and lignites — Determination of moisture content — Part 2: Indirect gravimetric method for moisture in the analysis sample ISO 5069-2, Brown coals and lignites — Principles of sampling — Part 2: Sample preparation for determination of moisture content and for general analysis ISO 13909-4, Hard coal and coke — Mechanical sampling — Part 4: Coal — Preparation of test samples Terms and definition No term s and defi nition s a re defi ne d i n th i s c ument ISO and IEC maintain terminological databases for use in standardization at the following addresses: — IEC Electropedia: available at http://www.electropedia.org/ — ISO Online browsing platform: available at http://www.iso.org/obp T he Principle s ample is bu rne d in an ox ygen b omb , the merc u r y s p e cie s forme d du ri ng combu s tion b ei ng ab s orb e d i n water T he merc u r y s p e cie s pre s ent i n the water are re duce d by s tan nou s ch loride a nd quanti fie d b y fla mele s s cold vap ou r atom ic ab s orp tion s p e c tro s cop y I t i s rep or te d that l ith ium b orohyd ride (L i B H ) a nd s o d iu m b orohyd ride (NaB H ) a re s ati s fac tor y for the reduction instead of stannous chloride; laboratories using these reductants should demonstrate that the performance is equivalent to that using stannous chloride Reagents WARNING — Care should be exercised when handling the reagents, many of which are toxic and corrosive D u ri ng the a na lys i s , u n le s s o ther wi s e s tate d , u s e on ly re agents o f re co gn i z e d ana lytic a l grade © ISO 2016 – All rights reserved ISO 15237:2016(E) , conforming to Grade of ISO 3696 5.1 Water 5.2 Oxygen , free fro m co mb us tib le matter and having a p urity o f at leas t 9 , 5.3 Nitric acid solution , % % by vo lume, p rep ared by diluting 0 ml o f co ncentrated nitric acid (relative dens ity , 42 ) to litre with water The % s o lutio n s hall have a mercury co ntent les s than 0,1 µg/l 5.4 Mercury standard stock solution , mercury in ml o f % ( 000 µg/ml, p rep ared by dis s o lving , V/V) nitric acid solution and diluting to 000 ml T he merc u r y s tandard s to ck s olution may a l s o b e prep are d from g o f high p urity com merc ia l ly avai lable cer ti fie d merc u r y s olution O ther h igh pu rity (> 9,9 %) merc u r y s a lts or oxide s may b e u s e d with appropri ate adj u s tment o f the mass taken 5.5 Mercury standard solution , 0,1 µg/ml f solution (5.4) to 500 ml with water and then diluting 10,0 ml of the intermediate solution to litre with water , p re p are d by diluti ng , ml o mercury s tandard s to ck T h i s merc u r y s ta nda rd s olution s hou ld b e prep a re d d ly 5.6 Potassium permanganate solution , g/l, p rep ared by dis s o lving g o f p o tas s ium p ermanganate (KMnO 4) in water and diluting to 100 ml T he merc u r y content o f the p o ta s s ium p ermanganate s hou ld b e b elow , µg/g 5.7 Hydroxylammonium chloride solution , g/l, p rep ared by dis s o lving , g o f hydroxylammo nium chloride (HONH Cl) in water and diluting to 100 ml T he merc u r y content o f the hyd rox yl am mon iu m ch loride s hou ld b e b elow , 0 µg/g 5.8 Reducing agent, stannous chloride solution , chlo ride dihydrate (S nC l ⋅2H 0 g/l, p rep ared by dis s o lving g o f s tanno us O ) in 45 ml o f co ncentrated hydro chlo ric acid s o lutio n (relative dens ity , ) and cautio us ly diluting to 0 ml with water T he merc u r y content o f the s tan nou s ch loride d i hyd rate s hou ld b e b elow , 01 µg/g NOTE See also Note to 10.2 re ga rd i n g the u s e o f flow i nj e c tion te ch n ique s Apparatus , capable of weighing to the nearest 0,1 mg 6.1 Balance 6.2 Oxygen combustion bomb , constructed in accordance with ISO 1928 The ignition wire shall be p latinum o r chro mium- nickel alloy The co mb us tio n b o mb s hall b e co ns tructed o f materials that are no t a ffected by the co mb us tio n p ro ces s o r p ro ducts I n p articular, the co mb us tio n b o mb s hall b e co ns tructed o f material that is nitric acid (5 free fro m ml, % mercury This can b e verified by was hing the interio r s ur faces with dilute V/V ) , and determining the mercury co ntent o f the was hings This s hall b e