1、BS ISO 622:2016Solid mineral fuels Determination of phosphoruscontent Reducedmolybdophosphatephotometric methodBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 622:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 622:2
2、016. It supersedes BS 1016-9:1977 which is withdrawn. The UK participation in its preparation was entrusted to TechnicalCommittee PTI/16, Solid mineral fuels.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include
3、all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2016. Published by BSI Standards Limited 2016ISBN 978 0 580 92525 2ICS 75.160.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British
4、Standard was published under the authority of theStandards Policy and Strategy Committee on 30 November 2016.Amendments/Corrigenda issued since publicationDate Text affectedBS ISO 622:2016 ISO 2016Solid mineral fuels Determination of phosphorus content Reduced molybdophosphate photometric methodComb
5、ustibles minraux solides Dosage du phosphore Mthode photomtrique au molybdophosphate rduitINTERNATIONAL STANDARDISO622Second edition2016-11-15Reference numberISO 622:2016(E)BS ISO 622:2016ISO 622:2016(E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll
6、 rights reserved. Unless otherwise specified, 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 fr
7、om either ISO at the address below or ISOs member 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 622:2016ISO 622:2016(E)Foreword iv1 Scope . 12 Normative
8、 references 13 Terms and definitions . 14 Principle 14.1 Extraction 14.2 Determination . 15 Reagents 26 Apparatus . 27 Sample preparation . 38 Procedure. 38.1 Dry oxidation method . 38.2 Wet oxidation method 48.3 Determination . 59 Expression of results 59.1 Method of calculation and formulae . 510
9、Precision of the method 610.1 Repeatability . 610.2 Reproducibility . 6 ISO 2016 All rights reserved iiiContents PageBS ISO 622:2016ISO 622:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of
10、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,
11、 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 maintenance are described in the ISO/
12、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).Attention is drawn to the possibility
13、 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 Introduction and/or on the ISO list of paten
14、t 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 conformity assessment, as well as informa
15、tion 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 minerals fuels, Subcommittee SC 5, Methods of analysis.This second
16、edition cancels and replaces the first edition (ISO 622:1981), which has been technically revised. This document incorporates changes related to references and other minor items following its systematic review.iv ISO 2016 All rights reservedBS ISO 622:2016INTERNATIONAL STANDARD ISO 622:2016(E)Solid
17、mineral fuels Determination of phosphorus content Reduced molybdophosphate photometric method1 ScopeThis document specifies a reduced molybdophosphate photometric method for the determination of the total phosphorus content of hard coal, lignites and coke. Two methods for taking the phosphorus into
18、solution are specified, namely extraction from the coal or coke ash with acid or by repeated oxidation of the coal or coke, by acid, to remove carbonaceous matter.2 Normative referencesThe following documents are referred to in the text in such a way that some or all of their content constitutes req
19、uirements 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 383, Laboratory glassware Interchangeable conical ground jointsISO 565, Test sieves Metal wire cloth, perfora
20、ted metal plate and electroformed sheet Nominal sizes of openingsISO 1171, Solid mineral fuels Determination of ashISO 18283, Hard coal and coke Manual sampling3 Terms and definitionsNo terms and definitions are defined in this document.ISO and IEC maintain terminological databases for use in standa
21、rdization at the following addresses: IEC Electropedia: available at http:/www.electropedia.org/ ISO Online browsing platform: available at http:/www.iso.org/obp4 Principle4.1 ExtractionMethod 1: Removal of carbonaceous material by ashing in a muffle furnace under specified conditions, and extractio
22、n of phosphorus by treatment with hydrofluoric and sulphuric acids.Method 2: Removal of carbonaceous material by repeated oxidation with nitric acid in the presence of sulphuric acid.4.2 DeterminationAddition of ammonium molybdate and ascorbic acid solution to the acid solution. Measurement of the a
23、bsorbance of the resulting blue solution by a suitable optical instrument. ISO 2016 All rights reserved 1BS ISO 622:2016ISO 622:2016(E)5 ReagentsDuring the analysis, use only reagents of recognized analytical grade and only distilled water or water of equivalent purity.5.1 Hydrofluoric acid, approxi
24、mately 400 g/l solution.WARNING Aqueous hydrofluoric acid is a highly corrosive liquid which attacks glass; the vapour is irritant and toxic. Its action on the skin and eyes is strongly corrosive, producing severe and painful burns which may not be immediately evident and which respond slowly to tre
25、atment. The solution should be handled only inside a well-ventilated fume cupboard. In the event of contact or suspected contact, flood with water and seek immediate medical attention. The manufacturers literature should be consulted for further information.5.2 Sulphuric acid, approximately 490 g/l
26、solution.5.3 Sulphuric acid, concentrated, 1,84 g/ml, approximately 98 % (m/m) solution.5.4 Nitric acid, concentrated, 1,42 g/ml, approximately 70 % (m/m) solution.5.5 Ammonium molybdate, 60 g/l solution.5.6 Ascorbic acid, 50 g/l solution.Prepare the solution fresh daily.5.7 Antimony potassium tartr
27、ate (KSbOC4H4O6), 1,36 g/l solution.5.8 Reagent solution.Mix 25 ml of the sulphuric acid solution (5.2), 10 ml of the ammonium molybdate solution (5.5), 10 ml of the ascorbic acid solution (5.6) and 5 ml of the antimony potassium tartrate solution (5.7). Prepare fresh immediately before use.5.9 Phos
28、phorus, standard stock solution corresponding to 0,100 g of P per litre.Weigh, to the nearest 0,000 1 g, 0,439 2 g of potassium dihydrogen monophosphate (KH2PO4) (dried at 110 C for 1 h) and dissolve in water. Transfer the solution quantitatively to a 1 000 ml one-mark volumetric flask, dilute to th
29、e mark and mix.1 ml of this standard stock solution contains 0,100 mg of P.5.10 Phosphorus, standard working solution corresponding to 1 mg of P per litre.Transfer 10 ml of the standard phosphorus solution (5.9) to a 1 000 ml one-mark volumetric flask, dilute to the mark and mix. Prepare fresh immed
30、iately before use.1 ml of this standard working solution contains 1 g of P.6 ApparatusOrdinary laboratory apparatus and6.1 Muffle furnace, as specified in ISO 1171.6.2 Dish, of silica, porcelain or platinum, as specified in ISO 1171.2 ISO 2016 All rights reservedBS ISO 622:2016ISO 622:2016(E)6.3 Ins
31、ulating plate, of silica, 6 mm thick, or its equivalent, of such size as to be an easy sliding fit into the muffle furnace (6.1).6.4 Platinum crucible, of capacity 25 ml to 30 ml, with lid.6.5 Hot-air bath.6.6 Digestion apparatus (see Figure 1), constructed of borosilicate glass, consisting of the f
32、ollowing:6.6.1 Flask, Kjeldahl flask, of capacity 300 ml, fitted with a 24/29 ground glass socket complying with ISO 383.6.6.2 Fume duct, of outside diameter approximately 28 mm, fitted with a dropping funnel of capacity at least 15 ml and a 24/29 ground glass cone complying with ISO 383. The fume d
33、uct may be of one piece or assembled from spate units by means of ground glass joints.6.6.3 Fume extractor, comprising a glass tube of diameter approximately 40 mm, sealed at one end and drawn out at the other end to form a connection to the water pump. The tube is fitted with a drain stopcock and a
34、 series of lipped holes to accommodate a number of fume ducts.6.7 Spectrophotometer, or photoelectric absorptiometer, of the required sensitivity.7 Sample preparationThe sample of coal or coke shall be the analysis sample, ground to pass a 212 m test sieve complying with the requirements of ISO 565,
35、 taken and prepared in accordance with ISO 18283. The sample shall be thoroughly mixed, preferably by a mechanical means, immediately before the determination.8 Procedure8.1 Dry oxidation method8.1.1 Determine the percentage of ash in the coal or coke as specified in ISO 1171. Grind the ash in an ag
36、ate mortar to pass a 63 m sieve complying with ISO 565.8.1.2 Weigh, to an accuracy of 0,1 mg, about 0,05 g of the ash into the platinum crucible (6.4).8.1.3 Add 2,0 ml of the sulphuric acid solution (5.2) and about 2,0 ml of the hydrofluoric acid solution (5.1). Place the lid on the crucible and dig
37、est on a boiling water bath for 30 min in a well-ventilated fume cupboard. Remove and rinse the lid, collecting the washings in the crucible. Allow the solution to evaporate on the water bath until most of the hydrofluoric acid and water have been removed.8.1.4 Transfer the crucible to the hot-air b
38、ath (6.5), evaporate until dense white fumes from the sulphuric acid have evolved for a few minutes. Allow to cool, add 0,5 ml of the sulphuric acid solution (5.2), heat for a few minutes and allow to cool.NOTE It is essential that the contents of the crucible are not evaporated completely to drynes
39、s at any stage. ISO 2016 All rights reserved 3BS ISO 622:2016ISO 622:2016(E)8.1.5 Add about 20 ml of water to the crucible and digest on the water bath for 30 min, when all the extract should be in one solution. Allow to cool, transfer the solution to a 100 ml one-mark volumetric flask and dilute wi
40、th water to the mark (solution A).If the sample has a high arsenic content, this can interfere with the result and the solution should be reduced before the phosphorus determination.8.1.6 Prepare a blank solution exactly as described above, but omitting the coal or coke ash.8.2 Wet oxidation method8
41、.2.1 Weigh, to an accuracy of 1 mg, about 1 g of the coal or coke sample.8.2.2 Transfer the test portion (8.2.1) to the clean, dry Kjeldahl flask (6.6.1). Assemble the apparatus (6.6) as shown in Figure 1, in a well-ventilated fume cupboard. Add 7 ml of the sulphuric acid (5.3) and 3,5 ml of the nit
42、ric acid (5.4) by means of the dropping funnel, rotating the flask so as to wash down any sample remaining in the neck.8.2.3 After the initial reaction has subsided, heat the flask carefully so that the reaction proceeds smoothly and without frothing. Continue heating the flask under the same condit
43、ions until only fumes of sulphuric acid are evolved. Add 0,2 ml to 0,4 ml of the nitric acid (5.4) to the dropping funnel and run the acid, drop by drop, into the flask.NOTE If violent frothing occurs on addition of the mixed acid, apply a damp cloth to the neck of the flask and heat intermittently
44、as the frothing subsides.8.2.4 Heat for 2 min to 3 min until no more dense brown fumes are evolved. Repeat the addition of the nitric acid and the heating, rotating the flask periodically to wash down any carbonaceous matter adhering to the sides of the flask, until all visible carbonaceous matter h
45、as been oxidized and the solution is a pale greenish-yellowish colour. This may take 1 1/2 h to 2 h, or even longer in exceptional cases with some coke samples.NOTE For the first 15 min of heating a coal sample, the reaction mixture is a tarry mass; subsequently, it changes its colour from black to
46、dark reddish-brown, to amber, and finally to a pale greenish-yellow. If a black liquid still remains after 45 min heating, eithera) too low a temperature has been used and the nitric acid has not reacted with the sample; raise thetemperature to distil off excess nitric acid, then continue the normal
47、 oxidation as described, orb) too high a temperature has been used, nitric acid being distilled off without reacting; cool, add more nitricacid and heat the mixture as described.8.2.5 Heat the flask more strongly until white fumes appear and allow to fume for 5 min. Cool the flask to approximately r
48、oom temperature, remove the dropping funnel and fume duct assembly and add a few glass beads to the contents of the flask.NOTE If the colour reverts to amber or deep red, add a further 0,2 ml to 0,4 ml of the nitric acid, heat to fuming and allow to fume for 5 min.8.2.6 Add cautiously 10 ml of water
49、, heat until white fumes appear and then allow to fume gently for 10 min. Cool the flask until the evolution of the white fumes ceases, add 0,2 ml of the nitric acid, reheat the flask and allow to fume for a further 10 min.8.2.7 To ensure complete oxidation, cool the flask to approximately room temperature and repeat the procedure described in 8.2.5.4 ISO 2016 All rights reservedBS ISO 622:2016ISO 622:2016(E)8.2.8 Cool the flask to approximately room temperature, add 10 ml of water, heat to fuming and allow to fume
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