BS ISO 334-2013 Solid mineral fuels Determination of total sulphur Eschka method《固体矿物燃料 总硫的测定 Eschka法》.pdf

1、BSI Standards PublicationBS ISO 334:2013Solid mineral fuels Determination of total sulfur Eschka methodBS ISO 334:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 334:2013. Itsupersedes BS 1016-106.4.1:1993 which is withdrawn.The UK participation in its pre

2、paration 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 all the necessaryprovisions of a contract. Users are responsible for its correctappli

3、cation. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 81995 7ICS 73.040; 75.160.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy

4、 Committee on 31 October 2013.Amendments issued since publicationDate Text affectedBS ISO 334:2013 ISO 2013Solid mineral fuels Determination of total sulfur Eschka methodCombustibles minraux solides Dosage du soufre total Mthode EschkaINTERNATIONAL STANDARDISO334Third edition2013-10-15Reference numb

5、erISO 334:2013(E)BS ISO 334:2013ISO 334:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All 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 pho

6、tocopying, 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 member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 4

7、7E-mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 334:2013ISO 334:2013(E) ISO 2013 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Principle 14 Reagents 14.1 Eschka mixture . 14.2 Hydrochloric acid 14.3 Potassium sulfate solution

8、24.4 Barium chloride, approximately 85 g/l solution . 24.5 Methyl red indicator solution . 24.6 Ammonia 24.7 Silver nitrate, 17 g/l solution 25 Apparatus . 25.1 Analytical balance. 25.2 Graduated glassware 25.3 Electrically heated muffle furnace . 25.4 Crucible 25.5 Flat plate . 25.6 Gooch crucible

9、. 25.7 Air oven . 26 Preparation of test sample . 37 Procedure. 37.1 Test portion 37.2 Charging the crucible . 37.3 Ignition . 47.4 Recovering the residue 47.5 Extraction 47.6 Precipitation of barium sulfate . 47.7 Blank testing . 58 Expression of results 59 Precision . 69.1 Repeatability limit 69.2

10、 Reproducibility limit 610 Test report . 6Annex A (informative) Derivation of factors used in the calculation in Clause 8 . 7BS ISO 334:2013ISO 334:2013(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The

11、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-gover

12、nmental, 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

13、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. www.iso.org/directivesAttention is drawn to the possibili

14、ty 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 pat

15、ent declarations received. www.iso.org/patentsAny trade name used in this document is information given for the convenience of users and does not constitute an endorsement.The committee responsible for this document is ISO/TC 27, Solid mineral fuels, Subcommittee SC 5, Methods of analysis.This third

16、 edition cancels and replaces the second edition (ISO 334:1992), of which it constitutes a minor revision.iv ISO 2013 All rights reservedBS ISO 334:2013ISO 334:2013(E)IntroductionAn alternative reference method to that specified in this International Standard is given in ISO 351:1996.Instrumental me

17、thods for a more rapid determination of total sulfur are now 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 as, or better

18、 than, those quoted for the reference method (see Clause 9). ISO 2013 All rights reserved vBS ISO 334:2013BS ISO 334:2013Solid mineral fuels Determination of total sulfur Eschka method1 ScopeThis International Standard specifies a reference method for determining the total sulfur content of hard coa

19、l, brown coals and lignites, and coke by the Eschka method.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the late

20、st edition of the referenced document (including any amendments) applies.ISO 687, Solid mineral fuels Coke Determination of moisture in the general analysis test sampleISO 1170, Coal and coke Calculation of analyses to different basesISO 5068-1, Brown coals and lignites Determination of moisture con

21、tent Part 1: Indirect gravimetric method for total moistureISO 5069-2, Brown coals and lignites Principles of sampling Part 2: Sample preparation for determination of moisture content and for general analysisISO 11722, Solid mineral fuels Hard coal Determination of moisture in the general analysis t

22、est sample by drying in nitrogenISO 13909-4, Hard coal and coke Mechanical sampling Part 4: Coal Preparation of test samples3 PrincipleA test portion is ignited in intimate contact with the Eschka mixture in an oxidizing atmosphere at 800 C to remove combustible matter and to convert the sulfur to s

23、ulfate. This is then extracted with hydrochloric acid solution and determined gravimetrically by precipitation with barium chloride.4 ReagentsWARNING Care should be exercised when handling the reagents, many of which are toxic and corrosive.During the analysis, unless otherwise stated, use only reag

24、ents of recognized analytical grade and only distilled water or water of equivalent purity.4.1 Eschka mixtureMix two parts by mass of light calcined magnesium oxide with one part by mass of anhydrous sodium (or potassium) carbonate. The mixture shall entirely pass a test sieve of 212 m nominal size

25、of openings.4.2 Hydrochloric acidConcentrated approximately 1,18 g/ml, approximately 36 % (m/m).INTERNATIONAL STANDARD ISO 334:2013(E) ISO 2013 All rights reserved 1BS ISO 334:2013ISO 334:2013(E)4.3 Potassium sulfate solutionWeigh, to the nearest 0,1 mg, about 2 g of potassium sulfate, previously dr

26、ied at a temperature of 105 C to 110 C. Dissolve in water and dilute to 1 l.4.4 Barium chloride, approximately 85 g/l solutionDissolve 100 g of barium chloride dihydrate in water and dilute to 1 l. Filter before use through a close-textured, doubly acid-washed filter paper or filter-paper pad.4.5 Me

27、thyl red indicator solutionDissolve 1 g of 2-(4-dimethylaminophenylazo) benzoic acid sodium salt (methyl red) in 1 l of water.4.6 AmmoniaConcentrated solution, not less than 25 % (m/m).4.7 Silver nitrate, 17 g/l solutionDissolve 17 g of silver nitrate in water and dilute to 1 l. Store in a dark, gla

28、ss bottle.5 Apparatus5.1 Analytical balanceCapable of weighing to the nearest 0,1 mg.5.2 Graduated glasswareConforming to the requirements for class A in the International Standards prepared by ISO/TC 48.5.3 Electrically heated muffle furnaceCapable of being maintained at a temperature of 800 C 25 C

29、. The ventilation through the muffle furnace shall be such as to give about five air changes per minute.5.4 CrucibleOf platinum, silica, or glazed porcelain, of capacity approximately 25 ml.5.5 Flat plate6 mm thick, of silica (or other suitable refractory material) which fits easily into the muffle

30、furnace (5.3).5.6 Gooch crucibleOf glazed porcelain or sintered glass.5.7 Air ovenCapable of being maintained at a temperature of 130 C 10 C.2 ISO 2013 All rights reservedBS ISO 334:2013ISO 334:2013(E)6 Preparation of test sampleThe test sample is the general analysis test sample prepared in accorda

31、nce with ISO 13909-4 or ISO 5069-2, as appropriate. Expose the sample, in a thin layer, for the minimum time required for the moisture content to reach approximate equilibrium with the laboratory atmosphere (this is particularly important for brown coals and lignites).Before commencing the determina

32、tion, thoroughly mix the test sample for at least 1 min, preferably by mechanical means.If the results are to be calculated other than on an “air-dried” basis (see Clause 8), then, after weighing the test portion (see 7.1), determine the moisture content using a further portion of the test sample by

33、 the method described in ISO 11722, ISO 687, or ISO 5068-1, as appropriate.7 Procedure7.1 Test portion7.1.1 For coalTake a test portion of the mass given in Table 1 (for the expected total sulfur content), weighing to the nearest 0,1 mg.Table 1 Test portion for coalExpected total sulphur content % (

34、m/m)Mass of test portion g101,00,50,257.1.2 For cokeTake a test portion of 1 g, weighing to the nearest 0,1 mg.7.2 Charging the crucibleCover the bottom of the crucible (5.4) uniformly with 0,5 g of the Eschka mixture (4.1), weighed to the nearest 0,1 mg. Mix the test portion intimately with 2,5 g o

35、f the Eschka mixture, weighed to the nearest 0,1 mg, in a suitable vessel. Transfer the mixture to the 25 ml crucible. Level the contents by tapping the crucible gently on the bench and cover the contents uniformly with 1,0 g of the Eschka mixture, weighed to the nearest 0,1 mg.The entire 4 g of the

36、 Eschka mixture should be weighed out and the 0,5 g and 1 g portions, required for the bottom and top layers, should be extracted from this. For this purpose, it is convenient to calibrate a small glass tube for each bath of the Eschka mixture to deliver 0,5 g and 1 g without weighing. The bottom la

37、yer of the Eschka mixture below the test portion mixture reduces attack on the porcelain surface so that the extraction of suIfate with hot water is complete even when the surface deteriorates. ISO 2013 All rights reserved 3BS ISO 334:2013ISO 334:2013(E)7.3 Ignition7.3.1 For coalPlace the charged cr

38、ucible (and any others up to the limit of the muffle furnace capacity) in the cold muffle furnace (5.3) and raise the temperature to 800 C 25 C in about 1 h, maintaining this temperature for at least a further 1,5 h. Withdraw the crucible (or crucibles) and allow to cool.NOTE The cracking of porcela

39、in crucibles can be prevented if they are slowly cooled by insertion in supports of light porous firebrick on removal from the muffle furnace.7.3.2 For cokePlace the charged crucible (or crucibles) on the cold insulating plate (5.5) and insert into the muffle furnace (5.3) at a temperature of 800 C

40、25 C, maintaining this temperature for at least a further 1,5 h. Withdraw the crucible (or crucibles) and allow to cool. See Note in 7.3.1.7.4 Recovering the residueTransfer the ignited mixture from the crucible to a 400 ml beaker containing 25 ml to 30 ml of water. If unburnt particles are present,

41、 the determination shall be stopped and the test repeated. Wash the crucible thoroughly with about 50 ml of hot water and add the washings to the contents of the beaker.7.5 ExtractionPlace a watch glass on the beaker and then, while tilting the watch glass, carefully add enough hydrochloric acid (4.

42、2) to dissolve the solid matter (17 ml will normally be required), warming the contents of the beaker to effect solution. Boil for 5 min to expel carbon dioxide and filter, collecting the filtrate in a 400 ml conical beaker.NOTE A medium-textured, doubly acid-washed filter paper or a filter-paper pa

43、d is recommended for speed of filtration.To prepare the filter-paper pad, shake doubly acid-washed filter-paper clippings, in pieces with areas of approximately 1 cm2, with water in a bottle until the paper is thoroughly disintegrated. Place a porcelain filter cone of 25 mm in a 75 mm funnel, close

44、the stem of the funnel with a finger, and add water until the cone is immersed and the funnel stem is full. Shake, onto the cone, sufficient paper pulp to form a pad 5 mm thick, and level it with a flat-ended glass rod. Allow the excess water to drain away by removing the finger from the stem and as

45、 drainage ceases, lightly tamp the pad around the edges with the glass rod. A final wash with water renders the filter ready for use.Wash the filter with five 20 ml portions of hot water.Add two or three drops of the methyl red indicator solution (4.5) to the combined filtrate and washings, and then

46、 cautiously add the ammonia solution (4.6) until the colour of the indicator changes and a trace of precipitate is formed. Add enough hydrochloric acid (4.2) to just redissolve the precipitate and then add 1 ml in excess.7.6 Precipitation of barium sulfateAfter extraction, dilute the solution, if ne

47、cessary, to approximately 200 ml and cover the beaker containing the solution with a watch glass. Heat the covered beaker until the solution boils and then reduce the heating slightly until ebullition of the solution ceases. Then add 10 ml of the cold barium chloride solution (4.4) from a pipette wi

48、th a delivery time of approximately 20 s so that the barium chloride solution falls into the centre of the hot solution while it is being agitated. Keep the solution just below boiling point for 30 min.4 ISO 2013 All rights reservedBS ISO 334:2013ISO 334:2013(E)Filter the solution using one of the f

49、ollowing techniques.a) By gravity through an ashless, close-textured, doubly acid-washed filter paper of diameter 100 mm to 125 mm. Carefully fold the filter paper and fit it into a fluted, long-stemmed 60 funnel so that the stem remains full of liquid during the filtration.b) By gravity through a filter-paper pad prepared from ashless, doubly acid-washed filter paper (see Note in 7.5).c) By suction through a pad of filtration mineral fibre in a Gooch crucible (5.6). Before commencing the filt