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1、BRITISH STANDARD BS 1016-106.6.1: 1997 ISO 587:1997 Methods for analysis and testing of coal and coke Part 106: Ultimate analysis of coal and coke Section 106.6 Determination of chlorine content Subsection 106.6.1 Eschka method ICS 75.160.10 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:
2、08:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1016-106.6.1:1997 This British Standard, having been prepared under the direction of the Sector Board for Materials and Chemicals, was published under the authority of the Standards Board and comes into effect on 15 September 1997 BSI 09-1999 ISBN
3、0 580 28417 4 National foreword This British Standard is the UK implementation of ISO 587:1997. Together with BS 1016-106.6.2 it will supersede BS 1016-8:1977. The UK participation in its preparation was entrusted to Technical Committee SFI/3, Analysis and testing of coal and coke, which has the res
4、ponsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. U
5、nder a scheme for the rationalizing and restructuring of BS 1016, the parts numbered from 1 to 21 are being gradually withdrawn and replaced with parts in a new series. The full list of parts in the new series, together with the corresponding numbering of the old series and related ISO standards is
6、given in BS 1016-100 General introduction and sampling report. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be found in
7、 the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are
8、 responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, the ISO title page, pages ii to iv, pages 1 to 5 and a back cover.
9、This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:08:16 GMT+00:00 20
10、06, Uncontrolled Copy, (c) BSI BS 1016-106.6.1:1997 BSI 09-1999i Contents Page National forewordInside front cover Forewordiii Text of ISO 5871 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:08:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun,
11、na, Fri Nov 24 08:08:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:08:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1016-106.6.1:1997 ii BSI 09-1999 Contents Page Forewordiii 1Scope1 2Normative references1 3Principle1 4Reagents1 5Apparatus
12、1 6Preparation of the test sample2 7Procedure2 8Expression of results3 9Precision4 10Test report4 Annex A (informative) Derivation of factors used in calculations in this International Standard5 Descriptors: Fossil fuels, solid fuels, coal, lignite, coke, chemical analysis, determination of content,
13、 chlorine, extraction methods. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:08:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1016-106.6.1:1997 BSI 09-1999iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO
14、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, govern
15、mental 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. Draft International Standards adopted by the technical committees are circulated to the
16、member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO 587 was prepared by Technical Committee ISO/TC 27, Solid mineral fuels, Subcommittee SC 5, Methods of analysis. This third edition can
17、cels and replaces the second edition (ISO 587:1981), which has been technically revised. Annex A of this International Standard is for information only. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:08:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun shef
18、fieldun, na, Fri Nov 24 08:08:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1016-106.6.1:1997 BSI 09-19991 1 Scope This International Standard specifies a method of determining the chlorine content of hard coal, brown coals and lignite, and coke using Eschka mixture. 2 Normative references The fo
19、llowing standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are e
20、ncouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 331:1983, Coal Determination of moisture in the analysis sample Direct gravimetric method. ISO 687
21、:1974, Coke Determination of moisture in the analysis sample. ISO 1015:1992, Brown coals and lignites Determination of moisture content Direct volumetric method. ISO 1170:1977, Coal and coke Calculation of analyses to different bases. ISO 1988:1975, Hard coal Sampling. ISO 2309:1980, Coke Sampling.
22、ISO 5068:1983, Brown coals and lignites Determination of moisture content Indirect gravimetric method. ISO 5069-2:1983, Brown coals and lignites Principles of sampling Part 2: Sample preparation for determination of moisture content and for general analysis. ISO 9411-1:1994, Solid mineral fuels Mech
23、anical sampling from moving streams Part 1: Coal. ISO 9411-2:1993, Solid mineral fuels Mechanical sampling from moving streams Part 2: Coke. 3 Principle A known mass of sample is ignited in intimate contact with Eschka mixture in an oxidizing atmosphere to remove combustible matter and to convert th
24、e chlorine to alkaline chlorides. These are extracted with nitric acid or water and determined by either the Volhard or the Mohr method, or by potentiometric titration using an Ion Selective Electrode (ISE). 4 Reagents WARNING Care should be exercised when handling reagents, many of which are toxic
25、and corrosive. During analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water, or water of equivalent purity. 4.1 For all methods 4.1.1 Eschka mixture Mix two parts by mass of light, calcined magnesium oxide with one part of anhydrous sodium or po
26、tassium carbonate. The mixture shall entirely pass a test sieve of 0,212 mm nominal aperture. 4.1.2 Nitric acid, concentrated, chlorine-free, approximately 70 % (m/m). 4.2 For the Volhard and ISE methods 4.2.1 Silver nitrate, standard volumetric solution, c(AgNO3) = 0,025 mol/l. Heat crushed, crysta
27、lline silver nitrate at 125 C for two to three hours. Dissolve 4,247 g in water and dilute to 1 l. Store in an amber glass bottle. 4.3 For the Volhard method only 4.3.1 3, 5, 5-trimethylhexan-1-ol. 4.3.2 n-Hexan-1-ol. 4.3.3 Potassium thiocyanate, standard volumetric solution, c(KSCN) . 0,025 mol/l.
28、Dissolve 2,4 g of potassium thiocyanate in water and dilute to 1 l. Titrate against the silver nitrate solution (4.2.1) and calculate the exact equivalence. 4.3.4 Iron(III) alum (ammonium iron(III) sulfate) indicator, saturated solution. Saturate 100 ml of water with approximately 125 g or iron(III)
29、 alum (NH4)2SO4 Fe2(SO4)3 24H2O and add sufficient nitric acid (4.1.2) to remove the brown colour. 4.4 For the Mohr method only 4.4.1 Silver nitrate, standard volumetric solution, c(AgNO3) = 0,050 mol/l. Weigh 8,494 g of silver nitrate, dried as in (4.2.1), dissolve in water and dilute to 1 l. Store
30、 in an amber glass bottle. 4.4.2 Potassium chromate, indicator solution. Dissolve 5 g of potassium chromate in 100 ml of water. 5 Apparatus 5.1 Analytical balance, capable of weighing to the nearest 0,1 mg. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:08:16 GMT+00:00 2006, Uncontrolled
31、Copy, (c) BSI BS 1016-106.6.1:1997 2 BSI 09-1999 5.2 Graduated glassware, conforming to the requirements for Grade A in the International Standards prepared by ISO/TC 48, Laboratory glassware and related apparatus. 5.3 Electrically heated muffle furnace, capable of being maintained at a temperature
32、of 675 C 25 C, with adequate ventilation. 5.4 Crucible, of platinum, silica or glazed porcelain, of approximately 25 ml capacity. 5.5 Flat plate, 6 mm thick, of silica or other suitable refractory material, which fits easily into the muffle furnace (5.3). 5.6 Potentiometric titration assembly, equip
33、ped with a chloride ion selective electrode and double junction reference electrode. 6 Preparation of the test sample The test sample is the general analysis test sample prepared in accordance with ISO 1988, ISO 2309, ISO 5069-2, ISO 9411-1 or ISO 9411-2 as appropriate. Ensure that the moisture cont
34、ent of the sample is in equilibrium with the laboratory atmosphere, exposing it, if necessary, in a thin layer for the minimum time required to achieve equilibrium. Before commencing the determination, thoroughly mix the equilibrated test sample for at least one minute, preferably by mechanical mean
35、s. 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 the method described in ISO 331, ISO 687, ISO 1015 or ISO 5068, as appropriate. 7 Pr
36、ocedure 7.1 Combustion Weigh, to the nearest 0,1 mg, a test portion of approximately 1 g, for samples with an expected chlorine content greater than 0,1 % (m/m), or 2 g for samples with a lower expected chlorine content. Cover the bottom of the crucible (5.4) uniformly with 0,5 g of the Eschka mixtu
37、re (4.1.1). Thoroughly mix the test portion with 2,5 g of the Eschka mixture in a suitable container. Transfer the mixture to the crucible, level the contents by gently tapping the crucible on the bench and cover uniformly with a further 1 g of the Eschka mixture. NOTE 1It is convenient to weigh out
38、 initially 4 g of the Eschka mixture and to extract the portions required for the bottom and top layers using a small glass tube, calibrated for each batch of Eschka mixture, to deliver 0,5 g and 1 g portions without weighing. The bottom layer of Eschka mixture reduces attack on silica and porcelain
39、 surfaces so that extraction of chlorine with hot water is complete even when the surface deteriorates. For coals, place the charged crucible in the cold muffle furnace (5.3) and raise the temperature to 675 C 25 C in about one hour. Maintain this temperature for a further two hours. Withdraw the cr
40、ucible and allow to cool. For coke, place the charged crucible on the cold flat plate (5.5) and insert into the muffle furnace at a temperature of 675 C 25 C. Maintain this temperature for two hours. Withdraw the crucible and allow to cool. NOTE 2Cracking of the porcelain crucibles is prevented if t
41、hey are cooled slowly by insertion into supports constructed from a light, porous refractory material after removal from the muffle furnace. 7.2 Completion Complete the determination by either the Volhard (7.2.1), the Mohr (7.2.2) or the ISE method (7.2.3). 7.2.1 Volhard method Transfer the incinera
42、ted mixture to a beaker, wash the crucible with about 125 ml of hot water and add the washings to the beaker. If unburnt particles are present, stop the test and repeat the determination, extending the combustion time. Cautiously add 20 ml of the nitric acid (4.1.2) and cover the beaker with a clock
43、 glass, swirling or stirring the contents, if necessary, to help dissolution. If necessary, filter the solution through a rapid-filtering, hardened, acid-washed filter paper, collecting the filtrate in a conical flask.1) Wash the paper with a small quantity of hot water (for example four lots of 5 m
44、l to 10 ml), cool to room temperature and add 20 ml of the silver nitrate solution (4.2.1) to the flask and mix thoroughly. Immediately add 5 ml of the 3, 5, 5-trimethylhexan-1-ol (4.3.1) or n-hexan-1-ol (4.3.2), shake the solution for one minute to coagulate the precipitate, add eight to ten drops
45、of the iron(III) alum indicator solution (4.3.4) and titrate with the potassium thiocyanate solution (4.3.3). The end-point is reached when the solution becomes faintly orange-pink in colour. 1) Filtration is usually unnecessary when using 1 g test portions of low-ash fuels, but is required when dea
46、ling with larger test portions or with high-ash fuels. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:08:16 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1016-106.6.1:1997 BSI 09-19993 7.2.2 Mohr method Transfer the incinerated mixture to a beaker, wash the crucible with hot water, collec
47、t the washings in the beaker and crush the residue in the beaker with a flat-ended glass rod. If unburnt particles are present, stop the determination and repeat the test extending the combustion time. Heat the solution to boiling point and filter, using a filter paper pad or rapid filtering paper,
48、collecting the filtrate in a conical flask. Wash the residue with five portions (5 ml each) of hot water, collecting the washings in the flask. Neutralize the solution with the nitric acid (4.1.2), using a pH paper. Add ten drops of the potassium chromate indicator (4.4.2) and titrate with the silve
49、r nitrate solution (4.4.1). The end-point is indicated by the first appearance of a brown coloration. 7.2.3 ISE method Transfer the incinerated mixture to a beaker, wash the crucible with 50 ml to 70 ml of hot water and add the washings to the beaker. If unburnt particles are present, stop the determination and repeat the test extending the combustion time. Cautiously add 20 ml of the nitric acid (4.1.2) and cover the beaker with a clock glass, swirling or stirring the contents, if necessary, to help dissolution. If