1、BRITISH STANDARD BS 1016-106.7: 1997 ISO 925:1997 Methods for analysis and testing of coal and coke Part 106: Ultimate analysis of coal and coke Section 106.7 Determination of carbonate carbon content ICS 75.160.10BSISO1016-106.7:1997 This British Standard, having been prepared under the directionof
2、 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 0 580 28416 6 National foreword This British Standard is the UK implementation of ISO925:1997. BS1016-106.7 will form a revision of Part
3、s6 to11 of BS1016. This section supersedes clauses5 and9 and 11 those parts of clause 11 relating to carbon (carbonate) as carbon dioxide in BS1016-6. The UK participation in its preparation was entrusted to Technical Committee SFI/3, Analysis and testing of coal and coke, which has the responsibili
4、ty 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. Under a sc
5、heme for the rationalizing and restructuring of BS1016, the parts numbered from1 to21 are being gradually withdrawn and replaced with parts in a new series.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 given in BS1
6、016-100 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 the BSI Stan
7、dards 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 responsible
8、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, theISOtitlepage, pages ii to iv, pages 1 to 4, an inside back cover and abackcov
9、er. 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. Date CommentsBSISO1016-106.7:1997 BSI 09-1999 i Contents Page National foreword Insi
10、de front cover Foreword iii Text of ISO 925 1ii blankBSISO1016-106.7:1997 ii BSI 09-1999 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Reagents 1 5 Apparatus 2 6 Preparation of the test sample 2 7 Procedure 2 8 Expression of results 4 9 Precision 4 10 Test report 4 An
11、nex A (informative) Derivation of factors used in calculationsinthisInternational Standard Inside back cover Figure 1 A suitable assembly of the apparatus 3 Table 1 Precision as carbonate carbon content 4 Table 2 Precision as carbon dioxide content 4 Table A.1 Inside back cover Descriptors: Fossil f
12、uels, solid fuels, carbonates, chemical analysis, determination of content, carbon, gravimetric analysis.BSISO1016-106.7:1997 BSI 09-1999 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of prep
13、aring 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, in
14、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 member bodies for voting. Public
15、ation as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO925 was prepared by Technical Committee ISO/TC27, Solid mineral fuels, Subcommittee SC5, Methods of analysis. This third edition cancels and replaces the second edition
16、(ISO925:1980), which has been technically revised. Annex A of this International Standard is for information only.iv blankBSISO1016-106.7:1997 BSI 09-1999 1 1 Scope This InternationalStandard specifies a gravimetric method of determining the carbon in the mineral carbonates associated with solid min
17、eral fuels. NOTEThe result obtained will include any carbon from atmospheric carbon dioxide absorbed by the fuel. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this International Standard. At the time of publication,
18、 the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this InternationalStandard are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of c
19、urrently valid International Standards. ISO 331:1983, Coal Determination of moisture in the analysis sample Direct gravimetric method. ISO 687:1974, Coke Determination of moisture in the analysis sample. ISO 1015:1992, Brown coals and lignites Determination of moisture content Direct volumetric meth
20、od. ISO 1170:1977, Coal and coke Calculation of analyses to different bases. ISO 1988:1975, Hard coal Sampling. ISO 2309:1980, Coke Sampling. ISO 5068:1983, Brown coals and lignites Determination of moisture content Indirect gravimetric method. ISO 5069-2:1983, Brown coals and lignites Principles of
21、 sampling Part 2: Sample preparation for determination of moisture content and for general analysis. ISO 9411-1:1994, Solid mineral fuels Mechanical 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 kno
22、wn mass of sample is treated with hydrochloric acid, which reacts with the carbonates present to liberate carbon dioxide. The carbon dioxide resulting from the decomposition of the carbonates is absorbed and weighed. 4 Reagents WARNING Care should be exercised when handling reagents, many of which a
23、re toxic and corrosive. During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only distilled water, or water of equivalent purity. NOTEDistilled water may be freed from carbon dioxide by boiling gently for15min. 4.1 Hydrochloric acid, approximately 3mol/l
24、. 4.2 Hydrogen sulfide absorbent Any of the following: a) copper(II) phosphate, granular, particle size1,2mm to0,7mm; NOTE 1Copper(II) phosphate granules may be prepared as follows: Mix copper(II) phosphate powdered reagent to a stiff paste with1% starch solution. Press through a sheet of metal, per
25、forated with apertures of approximately1mm diameter. Dry the extruded material at110 C. Sieve to recover the desired size fraction. b) copper(II) sulfate, deposited on a supporting base of ground pumice; NOTE 2A suitable absorbent, based on copper(II) sulfate, may be prepared as follows: Prepare pum
26、ice by crushing and sieving to obtain the2,8mm to0,7mm fraction. Transfer approximately60g of the prepared pumice to an evaporating basin, covering with a saturated solution of copper(II) sulfate, evaporate to dryness with constant stirring, and heat at150 C to160 C for3h to4h. Cool in a desiccator
27、and store in a glass-stoppered bottle. c) silver sulfate, granular. 4.3 Magnesium perchlorate, anhydrous, particle size1,2mm to0,7mm. WARNING Due regard must be taken of local regulations when disposing of exhausted magnesium perchlorate. It is essential that regeneration of magnesium perchlorate is
28、 not attempted, owing to the risk of explosion. 4.4 Sodium hydroxide, on an inert base, preferably of coarse grading, for example1,7mm to1,2mm, and preferably of the self-indicating type. 4.5 Wetting agent, suitable for use in acid solution. NOTEA liquid wetting agent at a concentration of100ml/l or
29、 ethanol 95% (V/V) are suitable. 4.6 Check test reagent Either of the following: a) anhydrous sodium carbonate; b) anhydrous calcium carbonate.BSISO1016-106.7:1997 2 BSI 09-1999 5 Apparatus 5.1 Analytical balance, capable of weighing to the nearest0,1mg. 5.2 Graduated glassware, conforming to the re
30、quirements for Grade A in the International Standards prepared by ISO/TC48, Laboratory glassware and related apparatus. 5.3 Purification tube, consisting of an absorption tube 1)containing sodium hydroxide on an inert base(4.4). 5.4 Reaction flask assembly, comprising a300ml round-bottomed flask fit
31、ted with a tap funnel, a double-surface condenser and a bulbed tube. 5.5 Absorption train, consisting of three absorption tubes a), b) and c) 1)packed respectively as follows: a) magnesium perchlorate (4.2) to dry the gas; b) hydrogen sulfide absorbent (4.2) followed by a protective layer of magnesi
32、um perchlorate (4.3). The connection from this tube to tube c) shall be fitted at its outlet end with a stopcock or other means of closure; c) sodium hydroxide on an inert base (4.4), to absorb carbon dioxide generated in the reaction flask, followed by a protective layer of magnesium perchlorate (4
33、.3) to absorb water produced in the reaction between carbon dioxide and sodium hydroxide. This tube shall be fitted with stopcocks or other means of closure at the inlet and outlet ends. 5.6 Air circulation equipment A suction pump, capable of drawing air at a rate of50ml/min through the apparatus,
34、connected through a flowmeter to a tee-piece fitted with a stopcock (the air vent). 5.7 Heating source, for the reaction flask. Either an electric heating mantle to accommodate a300ml flask or a small gas burner. An example of a suitable assembly of the apparatus is illustrated inFigure 1. 6 Prepara
35、tion of the test sample The test sample is the general analysis test sample prepared in accordance with ISO1988, ISO2309, ISO5069-2, ISO9411-1 or ISO9411-2 as appropriate. Ensure that the moisture content of the sample is in equilibrium with the laboratory atmosphere, exposing it, if necessary, in a
36、 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 means. If the results are to be calculated other than on an “air-dried” basis (seeclause8), then, after
37、 weighing the test portion (see7.2), determine the moisture content using a further portion of the test sample by the method described in ISO331, ISO687, ISO1015 or ISO5068, as appropriate. 7 Procedure 7.1 Check test Check the air-tightness of the apparatus and condition of the reagents by running a
38、 test according to the procedure described in7.2, but using approximately60mg of the check test reagent (4.6), weighed to the nearest0,1mg, instead of the test sample. Calculate the theoretical mass of carbon dioxide (seeA.2), expected to be liberated from the check test portion, and compare it with
39、 the measured value. The test is satisfactory if the measured value is within10% of the theoretical value; otherwise check the apparatus carefully to seal any leaks and/or replace the reagents. Re-test until a satisfactory result is obtained. Carry out check tests after initially setting up the appa
40、ratus, after having made any changes to it or to the reagents, and before making a determination or series of determinations. 7.2 Determination 7.2.1 Preparation Weigh accurately, to the nearest0,01g,5g of the sample into the reaction flask and add5 drops of the wetting agent (4.5) and100ml of water
41、. Close the flask by means of a rubber stopper and shake vigorously to wet the sample. Remove the stopper and wash any sample adhering to it back into the flask. Assemble the apparatus as shown inFigure 1, with the air vent closed. NOTEFor fuels containing more than0,5% carbonate carbon, the sample
42、mass may be reduced pro-rata, to a minimum of0,5g. 1) Absorption tubes may be U-tubes or Midvale tubes (which reduce back-pressure and hence, risk of leakage). The tops of the reagent columns should be covered with a layer of glass wool to guard against entrainment of any fine particles in the circu
43、lating air.BSISO1016-106.7:1997 BSI 09-1999 3 7.2.2 Conditioning Draw air through the apparatus at a rate of50ml/min for10min. Stop the circulation of air and close the ends of the carbon dioxide absorption tube and the outlet end of the hydrogen sulfide absorption tube connected to it. Remove the c
44、arbon dioxide absorption tube and wipe it with a clean, dry, lint-free cloth. NOTE 1Under certain conditions of humidity, wiping the absorbers with a cloth may induce a static charge, which, if significant, could affect the weighing. Consideration should therefore be given to employing static elimin
45、ators. Allow the tube to cool to the balance room temperature and weigh it at10min intervals until constant weight is obtained, i.e. two successive weighings do not differ by more than1mg. NOTE 2Tubes used for the absorption of carbon dioxide, particularly Midvale tubes, cool slowly and up to60min s
46、hould be allowed before weighing. When not connected to the apparatus, the tubes should be protected from atmospheric contamination by closing the taps and fitting guard seals of plugged rubber tubing to the open limbs. It is usual to weigh the absorption tubes without guard seals, after wiping. Fig
47、ure 1 A suitable assembly of the apparatusBSISO1016-106.7:1997 4 BSI 09-1999 7.2.3 Reaction and completion Reconnect the absorption tube to the apparatus and open the stopcocks or other closures in the absorption train. Place25ml of the hydrochloric acid (4.1) in the tap funnel, open the air vent an
48、d admit the acid to the reaction flask. Close the air vent and draw air through the system at a rate of about50ml/min. Raise the temperature of the liquid in the reaction flask slowly so that it boils after about15min. Continue boiling for a further30min, the rate of boiling being adjusted so that t
49、he condenser is not overloaded. Turn off the heating source, stop the circulation of air, remove the absorption tube, wipe clean and weigh as before (see7.2.2). 8 Expression of results Results may be expressed in terms of carbonate carbon content or carbon dioxide content, as appropriate, as follows. The carbonate carbon content of the sample W C , as analyzed, expressed as a percentage by mass, is given by the formula and the carbon dioxide content of the sample, , as analyzed, expressed as a percentage by mass, is gi
