1、BS ISO 622:2016 Solid mineral fuels Determination of phosphorus content Reduced molybdophosphate photometric method BSI Standards Publication WB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 622:2016 BRITISH STANDARD National foreword This British Standard is the UK implementation of I
2、SO 622:2016. It supersedes BS 1016-9:1977 which is withdrawn. The UK participation 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
3、 to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2016. Published by BSI Standards Limited 2016 ISBN 978 0 580 92525 2 ICS 75.160.10 Compliance with a British Standard cannot confer immunity from legal obligat
4、ions. This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 November 2016. Amendments/Corrigenda issued since publication Date Text affectedBS ISO 622:2016 ISO 2016 Solid mineral fuels Determination of phosphorus content Reduced molybdophosphate
5、 photometric method Combustibles minraux solides Dosage du phosphore Mthode photomtrique au molybdophosphate rduit INTERNATIONAL STANDARD ISO 622 Second edition 2016-11-15 Reference number ISO 622:2016(E)BS ISO 622:2016ISO 622:2016(E)ii ISO 2016 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2
6、016, Published in Switzerland All 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 permissio
7、n. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.orgBS ISO 622:2016ISO 622:
8、2016(E)Foreword iv 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Principle 1 4.1 Extraction 1 4.2 Determination . 1 5 Reagents 2 6 Apparatus . 2 7 Sample preparation . 3 8 Procedure. 3 8.1 Dry oxidation method . 3 8.2 Wet oxidation method 4 8.3 Determination . 5 9 Expression of
9、 results 5 9.1 Method of calculation and formulae . 5 10 Precision of the method 6 10.1 Repeatability . 6 10.2 Reproducibility . 6 ISO 2016 All rights reserved iii Contents PageBS ISO 622:2016ISO 622:2016(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation
10、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. I
11、nternational 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. The procedures used to develop this document and those
12、 intended for its further maintenance 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 (se
13、e www.iso.org/directives). 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. Details of any patent rights identified during the development of the docu
14、ment 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 information given for the convenience of users and does not constitute an endorsement. For an explanation on the meaning of ISO specific terms an
15、d expressions related to conformit y 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
16、 minerals fuels, Subcommittee SC 5, Methods of analysis. This second 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 right
17、s reservedBS ISO 622:2016INTERNATIONAL ST ANDARD ISO 622:2016(E) Solid mineral fuels Determination of phosphorus content Reduced molybdophosphate photometric method 1 Scope This document specifies a reduced molybdophosphate photometric method for the determination of the total phosphorus content of
18、hard coal, lignites and coke. Two methods for taking the phosphorus into 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 references The following documents are referred to
19、in the text in such a way that some or all of their content constitutes requirements 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 Interch
20、angeable conical ground joints ISO 565, Test sieves Metal wire cloth, perforated metal plate and electroformed sheet Nominal sizes of openings ISO 1171, Solid mineral fuels Determination of ash ISO 18283, Hard coal and coke Manual sampling 3 T erms a nd definiti ons No terms and definitions are defi
21、ned 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/obp 4 Principle 4.1 Extraction Method 1: Removal of c
22、arbonaceous material by ashing in a muffle furnace under specified conditions, and extraction 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 Determination Addit
23、ion of ammonium molybdate and ascorbic acid solution to the acid solution. Measurement of the absorbance of the resulting blue solution by a suitable optical instrument. ISO 2016 All rights reserved 1BS ISO 622:2016ISO 622:2016(E) 5 Reagents During the analysis, use only reagents of recognized analy
24、tical grade and only distilled water or water of equivalent purity. 5.1 Hy dr ofluoric acid, approximately 400 g/l solution. W A R N I N G Aq u e o u s h y d r o f l u o r i c a c i d i s a h i g h l y c o r r o s i v e l i q u i d w h i c h a t t a c k s g l a s s ; t h e v a p o u r i s i r r i t
25、a n t a n d t o x i c . I t s a c t i o n o n t h e sk i n a n d e y e s i s s t r o n g l y c o r r o s i v e , p r o d u c i n g severe and painful burns which may not be immediately evident and which respond slowly to treatment. The solution should be handled only inside a well-ventilated fume cu
26、pboard. In the e v e n t o f c o n t a c t o r s u s p e c t e d c o n t a c t , f l o o d w i t h w a t e r a n d s e e k i m m e d i a t e m e d i c a l a t t e n t i o n . The manufacturers literature should be consulted for further information. 5.2 Sulphuric acid, approximately 490 g/l solution.
27、 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 tartrate
28、 (KSbOC 4 H 4 O 6 ), 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.
29、9 Phosphorus, 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 (KH 2 PO 4 ) (dried at 110 C for 1 h) and dissolve in water. Transfer the solution quantitatively to a 1 000 ml one-mark volumetric flask, d
30、ilute to the 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. Prepa
31、re fresh immediately before use. 1 ml of this standard working solution contains 1 g of P. 6 Apparatus Ordinary laboratory apparatus and 6.1 Muffle furnac e, 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 622:2016IS
32、O 622:2016(E) 6.3 Insulating 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 gl
33、ass, consisting of the following: 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 complyin
34、g with ISO 383. The fume duct 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
35、with a drain stopcock and a series of lipped holes to accommodate a number of fume ducts. 6.7 Spectrophotometer, or photoelectric absorptiometer, of the required sensitivity. 7 Sample preparation The sample of coal or coke shall be the analysis sample, ground to pass a 212 m test sieve complying wit
36、h the requirements of ISO 565, taken and prepared in accordance with ISO 18283. The sample shall be thoroughly mixed, preferably by a mechanical means, immediately before the determination. 8 Procedure 8.1 Dry oxidation method 8.1.1 Determine the percentage of ash in the coal or coke as specified in
37、 ISO 1171. Grind the ash in an agate 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). Pl
38、ace the lid on the crucible and digest 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 Tr
39、ansfer the crucible to the hot-air bath (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 ar
40、e not evaporated completely to dryness 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 o
41、ne-mark volumetric flask and dilute with 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 co
42、al or coke ash. 8.2 Wet oxidation method 8.2.1 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
43、 sulphuric acid (5.3) and 3,5 ml of the nitric 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. Cont
44、inue heating the flask under the same conditions 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 t
45、he neck of the flask and heat intermittently 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
46、flask, until all visible carbonaceous matter has 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; sub
47、sequently, it changes its colour from black to dark reddish-brown, to amber, and finally to a pale greenish-yellow. If a black liquid still remains after 45 min heating, either a) too low a temperature has been used and the nitric acid has not reacted with the sample; raise the temperature to distil
48、 off excess nitric acid, then continue the normal oxidation as described, or b) too high a temperature has been used, nitric acid being distilled off without reacting; cool, add more nitric acid and heat the mixture as described. 8.2.5 Heat the flask more strongly until white fumes appear and allow
49、to fume for 5 min. Cool the flask to approximately room 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, 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,
