1、BS ISO 11724:2016Solid mineral fuels Determination of total fluorinein coal, coke and fly ashBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 11724:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 11724:2016. The UK pa
2、rticipation in its preparation was entrusted to Technical Committee PTI/16, Solid mineral fuels.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are respons
3、ible for its correct application. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 92527 6 ICS 73.040 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards
4、Policy and Strategy Committee on 31 December 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 11724:2016 ISO 2016Solid mineral fuels Determination of total fluorine in coal, coke and fly ashCombustibles minraux solides Dtermination de la teneur totale en fluor da
5、ns le charbon, le coke et les cendresINTERNATIONAL STANDARDISO11724Second edition2016-12-01Reference numberISO 11724:2016(E)BS ISO 11724:2016ISO 11724:2016(E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights reserved. Unless otherwise specified,
6、 no part of 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 ISOs me
7、mber body in the country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 11724:2016ISO 11724:2016(E)Foreword iv1 Scope . 12 Normative references 13 Terms and definitions . 14
8、 Principle 15 Reagents 16 Apparatus . 27 Sample . 57.1 Coal and coke 57.2 Fly ash . 58 Procedure. 58.1 Number of determinations . 58.2 Preparation of test sample 58.3 Blank tests . 58.4 Pyrohydrolysis procedure . 58.4.1 Apparatus conditioning . 58.4.2 Pyrohydrolysis . 58.4.3 Pyrohydrolysate processi
9、ng . 68.5 Solution measurement . 68.5.1 General 68.5.2 Direct-comparison ISE method . 68.5.3 Analyte-addition ISE method 78.5.4 IC method . 79 Calculations 89.1 General . 89.2 Direct-comparison ISE method 89.3 Analyte-addition ISE method . 99.4 IC method 910 Expression of result . 911 Precision 1011
10、.1 Repeatability limit . 1011.2 Reproducibility critical difference 1012 Test report 10Bibliography .11 ISO 2016 All rights reserved iiiContents PageBS ISO 11724:2016ISO 11724:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodi
11、es (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
12、, 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.The procedures used to develop this document and those intended for its further m
13、aintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).A
14、ttention 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. Details of any patent rights identified during the development of the document will be in the Introduc
15、tion and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to confo
16、rmity assessment, as well as information about ISOs 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
17、5, Methods of analysis.This second edition cancels and replaces the first edition (ISO 11724:2004), of which it constitutes a minor revision. This document incorporates changes related to dated references and other minor items following its systematic review.iv ISO 2016 All rights reservedBS ISO 117
18、24:2016INTERNATIONAL STANDARD ISO 11724:2016(E)Solid mineral fuels Determination of total fluorine in coal, coke and fly ash1 ScopeThis document specifies a method for the determination of total fluorine in coal, coke and fly ash.From measurement of the total fluorine alone, it is not possible to es
19、timate the amount of fluorine released to the environment by utilization of the coal and subsequent disposal of the ash residue.2 Normative referencesThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dat
20、ed references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 589, Hard coal Determination of total moistureISO 687, Solid mineral fuels Coke Determination of moisture in the general analysis test sampleISO
21、 5068-2, Brown coals and lignites Determination of moisture content Part 2: Indirect gravimetric method for moisture in the analysis sampleISO 5069-2, Brown coals and lignites Principles of sampling Part 2: Sample preparation for determination of moisture content and for general analysisISO 11722, S
22、olid mineral fuels Hard coal Determination of moisture in the general analysis test sample by drying in nitrogenISO 13909-4, Hard coal and coke Mechanical sampling Part 4: Coal Preparation of test samplesISO 13909-6, Hard coal and coke Mechanical sampling Part 6: Coke Preparation of test samples3 Te
23、rms and definitionsNo terms and definitions are defined in this document.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/obp4 P
24、rincipleMixing of the sample of coal, coke or fly ash with silica, and pyrohydrolysis in a tube furnace at approximately 1 200 C in an atmosphere of oxygen and water vapour. Absorption of the volatilized fluorine compounds in a suitable solution and processing for determination by ion-selective elec
25、trode (ISE) or ion chromatographic (IC) techniques.5 ReagentsCAUTION Care shall be exercised when handling reagents, some of which are toxic and corrosive. ISO 2016 All rights reserved 1BS ISO 11724:2016ISO 11724:2016(E)During the analysis, use only reagents of recognized analytical grade and only d
26、istilled water, or water of equivalent purity.5.1 Silica of top size 75 m, ignited at 1 000 C for 1 h.CAUTION Fine silica is dangerous to health if inhaled.5.2 Solutions for ISE measurement5.2.1 Standard fluorine solution (1 g contains 200 g of F).a) For direct-comparison methodDissolve 0,221 0 g 0,
27、000 2 g of dry (110 C for 1 h) sodium fluoride in approximately 400 ml of water contained in a tared plastic bottle, dilute to 500 g 0,5 g net with water, and mix.b) For analyte-addition methodDissolve 0,221 0 g 0,000 2 g of dry (110 C for 1 h) sodium fluoride in a tared plastic bottle containing 15
28、0 ml of water and 100 g of buffer (5.2.3). Dilute to 500 g 0,5 g net with water and mix.5.2.2 Absorption solution (0,025 mol/l NaOH).Dissolve 2,0 g of sodium hydroxide in about 500 ml of water. Transfer to a tared 2,5 l plastic bottle, dilute to 2 000 g net with water, and mix.5.2.3 Buffer (pH 6,5).
29、Dissolve 10,0 g of potassium nitrate, 5 g of 1,2-cyclohexylenedinitrilotetraacetic acid (CDTA) and 115 g of ammonium acetate in 350 ml of water. Adjust the pH to 6,5 with glacial acetic acid. Dilute to 500 g net with water and mix.5.2.4 Solution for conditioning fluoride ISE.Weigh 20 g of water, 20
30、g of absorption solution (5.2.2) and 10 g of buffer (5.2.3) into a polystyrene vial (6.2). Add approximately 200 mg of standard fluorine solution of 5.2.1 a) or 5.2.1 b) and mix.5.3 Solutions for IC measurement5.3.1 Standard fluorine solution (1 g contains 200 g of F).Dissolve 0,221 0 0,000 2 g of d
31、ry (110 C for 1 h) sodium fluoride in approximately 400 ml of water contained in a tared plastic bottle, dilute to 500 g 0,5 g net with water, and mix.5.3.2 Absorption solution for IC measurement.Dissolve 0,300 g of sodium hydrogen carbonate and 1,120 g of sodium carbonate in approximately 500 ml of
32、 water and dilute to 2 l.5.4 Oxygen, compressed.6 Apparatus6.1 Vials, made of glass or polystyrene, of capacity 10 ml to 30 ml with tightly fitting snap-on plastic caps.2 ISO 2016 All rights reservedBS ISO 11724:2016ISO 11724:2016(E)6.2 Polypropylene bottles or polystyrene vials, tared, of capacity
33、125 ml, wide necked with linerless leak-proof screw caps.6.3 Balances: a balance capable of weighing to the nearest 0,000 1 g; a balance capable of weighing approximately 200 g to the nearest 0,001 g; a balance capable of weighing 600 g to the nearest 0,01 g; and a balance capable of weighing 3 000
34、g to the nearest 0,1 g.6.4 Polyethylene dispensing bottles, for the standard fluorine solution (5.2.1), absorption solution (5.2.2) and buffer (5.2.3).6.5 Micropipette, of variable volume, ranging to at least 1 ml.This is a satisfactory alternative to the 250 ml polyethylene dispensing bottle (6.4)
35、for delivery of small weighed volumes of standard fluorine solution (5.2.1).6.6 Apparatus for tube-furnace pyrohydrolysis (see Figure 1).6.6.1 Steam generator, consisting of the following:a) round-bottom flask, 2 l capacity;b) heating mantle, 2 l capacity;c) Y-piece, glass, 10 mm diameter;d) oxygen
36、distribution tube, porosity 0;e) stopcocks, one three-way and one two-way.6.6.2 Silica-tube furnace and accessories.The apparatus is similar to that used in ISO 351.a) Silica tube, made of pure silica (25 mm outer diameter, 20 mm inner diameter), of length (typically 700 mm) appropriate to the parti
37、cular furnace used (generally of an approximate length of 400 mm). Preferably, the gas outlet end should be narrowed to a tubule of approximately 7 mm diameter.NOTE Combustion tubes of alternative refractory compositions do not have adequate thermal stress characteristics for operation with this met
38、hod.b) Silicone stoppers, 20 mm diameter, positioned at inlet end (and outlet, if applicable) of the silica tube described in a).c) Combustion boats, made of high-alumina unglazed porcelain (approximately 97 mm 16 mm 12 mm), preignited at 1 000 C for 1 h.d) Silica pusher and T-tube, comprising a sil
39、ica push rod (5 mm diameter and 500 mm long) fused at one end to provide a flat disc surface of 10 mm to 12 mm diameter, and having a piece of magnetic steel affixed to the other end by epoxy resin. The T-tube (500 mm long) is composed of borosilicate glass and protrudes 10 mm into the silica tube a
40、) through a stopper b). The stem of the T-tube is connected to the steam generator by way of the three-way stopcock 6.6.1 e). A magnet is used to move the pusher inside the T-tube.e) Combustion furnace, capable of reaching a temperature of at least 1 200 C.6.6.3 Absorption vessel: Dreschel gas washi
41、ng bottle or equivalent, of capacity 125 ml, with gas-distribution tube fitted with a sintered glass disc of 15 m to 40 m pore size 6.6.1 d) bent at 90, approximately 60 mm from the top. ISO 2016 All rights reserved 3BS ISO 11724:2016ISO 11724:2016(E)6.6.4 Water jacket, suitable for containing the a
42、bsorption vessel.Key1 stopcock 8 combustion boat 15 heating mantle2 Y-piece 9 silica tube 16 oxygen in3 round-bottom flask 10 cooling water 17 three-way stopcock4 stopcock 11 absorption vessel 18 steam distribution tube5 T-piece 12 water jacket 19 to sink6 silica pusher 13 thermocouple7 furnace 14 s
43、ilicone stopperFigure 1 Schematic diagram of pyrohydrolysis apparatus6.7 ISE measurement apparatus6.7.1 Magnetic stirrer, complete with polytetrafluoroethylene stirring bars.6.7.2 Electrodes: a solid state fluoride ion selective electrode and a reference electrode.The sensing element of the fluoride
44、 electrode should be polished on each day of use to prolong optimal performance. This may be achieved, for example, by using 0,25 mm diamond dust or alumina sprayed on a polishing cloth, and polishing the electrode for 30 s to 60 s. The electrode, having been stored dry, is conditioned for at least
45、30 min prior to use, by insertion in a conditioning solution (5.2.4).6.7.3 Millivoltmeter, having a resolution of 0,1 mV.6.8 IC measurement apparatus, equipped with a chromatography pump, anion separation columns, conductivity detector and integrator.4 ISO 2016 All rights reservedBS ISO 11724:2016IS
46、O 11724:2016(E)7 Sample7.1 Coal and cokeThe test sample is the general analysis sample prepared in accordance with ISO 5069-2, ISO 13909-4 or ISO 13909-6, as appropriate.7.2 Fly ashFly ash normally has a top particle size of less than 75 m and therefore may not require any reduction prior to analysi
47、s. However, special care shall be taken in the collection and preparation of representative samples and in avoiding contamination.8 Procedure8.1 Number of determinationsThe analysis should be carried out in duplicate on separate test portions of the coal, coke or fly ash.8.2 Preparation of test samp
48、leThe test sample mass taken for the analysis is dependent upon the mass fraction of fluorine present. The following procedure assumes mass fractions of fluorine up to a maximum of 2 000 g/g. If higher fluorine mass fractions are anticipated or found to be present, proportionately lower sample masse
49、s shall be taken to ensure maximal recovery of fluorine from the sample matrix.Accurately weigh 250 mg, to the nearest 0,1 mg, of the coal, coke or fly ash (this is the sample mass, ms) and mix well with 250 mg 5 mg of silica (5.1) in a vial (6.1). If calculation to bases other than as-received is required, concurrently weigh another sample for determination of the moisture in the coal, coke or fly ash by one of the methods specified in ISO 589, ISO 11722, ISO 5068-2 or IS
