BS 6043-1 3-1983 Methods of sampling and test for carbonaceous materials used in aluminium manufacture - Electrode pitch - Determination of softening point (ring and ball method)《制.pdf

1、BRITISH STANDARD BS 6043-1.3: 1983 ISO 5940:1981 Methods of sampling and test for Carbonaceous materials used in aluminium manufacture Part 1: Electrode pitch Section 1.3 Determination of softening point (ring and ball method) ISO title: Carbonaceous materials for the production of aluminium Pitch f

2、or electrodes Determination of softening point by the ring and ball method UDC 665.775:669.713.7:536.421.2BS6043-1.3:1983 This British Standard, having been prepared under thedirectionof the ChemicalsStandards Committee,was published underthe authorityof theBoardof BSIand comesintoeffect on 31May198

3、3 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference CIC/24 Draft for comment 78/56456 DC ISBN 0 580 11909 2 Cooperating organizations The Chemicals Standards Committee, under whose direction this British Standard was prepared, consists of representativ

4、es from the following: Association of Fatty Acid Distillers British Tar Industry Association* Chemical Industries Association Consumer Standards Advisory Committee of BSI Department of Health and Social Security Department of Industry (Laboratory of the Government Chemist) Fertiliser Manufacturers A

5、ssociation Ltd. Ministry of Agriculture, Fisheries and Food Ministry of Defence National Sulphuric Acid Association Paintmakers Association of Great Britain Ltd. Royal Institute of Public Health and Hygiene Royal Society of Chemistry Soap and Detergent Industry Association Standardization of Tar Pro

6、ducts Tests Committee* The organizations marked with an asterisk in the above list, together with the following, were directly represented on the Technical Committee entrusted with the preparation of this British Standard: Aluminium Federation British Ceramic Research Association Institute of Petrol

7、eum Amendments issued since publication Amd. No. Date of issue CommentsBS6043-1.3:1983 BSI 10-1999 i Contents Page Cooperating organizations Inside front cover National foreword ii 1 Scope and field of application 1 2 Reference 1 3 Principle 1 4 Reagents 1 5 Apparatus 1 6 Procedure 1 7 Expression of

8、 results 2 8 Test report 2 Annex A Details of thermometers 3 Annex B Melting of pitch samples 3 Figure 1 Assembled apparatus 4 Figure 2 Tapered ring 5 Figure 3 Recommended form of ball centring guide 5 Figure 4 Support for rings 6 Figure 5 Plate for moulding 6 Publications referred to Inside back co

9、verBS6043-1.3:1983 ii BSI 10-1999 National foreword This British Standard has been prepared under the direction of the Chemicals Standards Committee to provide methods of sampling and test for carbonaceous materials used in the production of aluminium. The standard will be published in two Parts, ea

10、ch Part being divided into Sections. The two Parts are: Part 1: Electrode pitch; Part 2: Electrode coke. Initially, it is proposed that Part 1 will comprise the following Sections: Other international methods of test for electrode pitch are under consideration and, subject to approval by the United

11、Kingdom, will be published as they become available. This Section is identical with ISO5940:1981 “Carbonaceous materials for the production of aluminium Pitch for electrodes Determination of softening point by the ring and ball method”, published by the International Organization for Standardization

12、 (ISO). Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British Standards; attention is drawn especially to the fol

13、lowing. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be read as “British Standard”. Section Subject Ident

14、ical with 1.1 Sampling ISO 6257 1.2 Water content (Dean and Stark method) ISO 5939 1.3 Softening point (ring and ball method) ISO 5940 1.4 Content of toluene-insoluble material ISO 6376 1.5 Content of quinoline-insoluble material ISO 6791 1.6 Coking value ISO . . . . a 1.7 Density ISO . . . . a 1.8

15、Ash content ISO . . . . a 1.9 Sulphur content ISO . . . . a a In course of preparation and referred to for information purposes only. Cross-reference International Standard Corresponding British Standard ISO 6257:1980 BS 6043 Methods of sampling and test for carbonaceous materials used in aluminium

16、manufacture Part 1 Electrode pitch Section 1.1:1981 Sampling (Identical)BS6043-1.3:1983 BSI 10-1999 iii Additional information. This standard describes methods of test only, and should not be used or quoted as a specification defining limits of purity. Reference to this Section should state that the

17、 method of test used is in accordance with BS6043-1.3:1983. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from

18、legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages1 to 6, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment t

19、able on the inside front cover.iv blankBS6043-1.3:1983 BSI 10-1999 1 1 Scope and field of application This International Standard specifies a method of using the ring-and-ball apparatus for the determination of the softening point (softening temperature) of pitch used in the production of aluminium.

20、 The method is applicable to pitches having softening points equal to or greater than30 C. 2 Reference ISO 6257, Carbonaceous materials used in the production of aluminium Pitch for electrodes Sampling. 3 Principle Preparation of a disc-shaped test piece by moulding a test portion in a ring, fitting

21、 the prepared ring into a heated bath and placing a steel ball on the upper surface of the test piece. Determination of the temperature at which the test piece, on heating at a prescribed rate, softens sufficiently to sag to a specified depth under the mass of the ball. This temperature corresponds

22、to the softening point (softening temperature). 4 Reagents During the analysis, use only reagents of recognized analytical grade and distilled water, or water of equivalent purity, freshly boiled and cooled. 4.1 Glycerol, for use with pitches having softening points greater than85 C. 4.2 Water, for

23、use with pitches having softening points in the range30 to85 C. 5 Apparatus Ordinary laboratory apparatus and 5.1 Ring-and-ball apparatus (seeFigure 1 for assembled apparatus), comprising: 5.1.1 Rings, brass, tapered (seeFigure 2), having the following dimensions: depth: 6,4 0,1 mm; internal diamete

24、r at bottom: 15,9 0,1 mm; internal diameter at top: 17,5 0,1 mm; external diameter above shoulder: 20,6 0,1mm; external diameter below shoulder: 18,5 0,5mm. 5.1.2 Steel balls, of diameter9,53mm, each weighing3,50 0,05g. 5.1.3 Ball centring guides A suitable form of guide is shown inFigure 3. 5.1.4 B

25、ath; a heat-resistant glass squat form beaker of capacity800ml. 5.1.5 Ring support, having the shape and dimensions shown inFigure 1 andFigure 4. The support consists essentially of two parallel brass plates, one above the other, and25 0,5mm apart. The upper plate is designed to support the two ring

26、s (5.1.1) and its thickness is equal to the distance between the lower surface of one ring and its shoulder. The two plates are supported by a circular or rectangular holder which rests on the top of the bath and which has a central hole intended for the thermometer (5.1.6). 5.1.6 Thermometer, solid

27、-stem, mercury-in-glass type, having: a) a range from0 to120 C for pitches which have softening points between30 and120 C; b) a range from50 to210 C for pitches which have softening points greater than120 C. Details of suitable thermometers are given in Annex A, but other thermometers of similar cha

28、racteristics may also be used. 5.1.7 Tripod and open mesh wire gauze, supporting the bath (5.1.4). 5.1.8 Bunsen burner, fitted with a governor if the gas supply is liable to fluctuate. 5.1.9 Moulding plate, having the dimensions shown inFigure 5. 5.2 Draught screen, of suitable design to protect the

29、 assembled apparatus from draughts. NOTEIt is also possible to use an automatic ring-and-ball apparatus in place of the manual apparatus, provided that it has the same dimensions and that the same results are obtained. 6 Procedure 6.1 Preparation of test piece Using the method specified inAnnex B, m

30、elt a test portion of approximately50g of the laboratory sample (see ISO6257, sub-clause 3.10) and heat the rings (5.1.1). Place the heated rings in the sets of guide pins on the moulding plate (5.1.9), which shall have been treated to prevent adhesion of the pitch, and immediately pour the pitch in

31、to the rings in a steady stream.BS6043-1.3:1983 2 BSI 10-1999 The quantity of pitch used for each ring shall be such that, after 20min, a slight excess remains above the level of the ring. At the end of the cooling period, remove the excess with a knife, but without applying heat. It is essential th

32、at the two rings be filled from a single melt and that they be tested together. 6.2 Preparation of the apparatus Avoiding any aeration, place in the bath (5.1.4) a sufficient amount (600ml is usually adequate) of either the glycerol (4.1) or the water (4.2) so that the level is at least50mm above th

33、e top of the rings. The liquid shall be previously cooled, if necessary, to at least45 C below the expected softening point of the pitch, with the exception that, for soft pitches, the temperature should not be below5 C. Place the prepared rings on their support (5.1.5) and fit this assembly into th

34、e bath. Insert the appropriate thermometer (5.1.6) coaxially in the beaker, so that the bottom of its bulb is at the level of the lower surface of the rings and is equidistant from each. Place the ball centring guides (5.1.3) above each ring and place two of the balls (5.1.2) in the bath, but not on

35、 the pitch contained in the rings. Place the beaker on the tripod (5.1.7) so that the ring supporting holder is horizontal. Allow the assembled apparatus to stand for15min without allowing the temperature of the bath to rise, and then, using tongs, place the balls in their guides on the surface of t

36、he discs of pitch. 6.3 Determination Place the Bunsen burner (5.1.8) midway between the axis and the edge of the beaker and on a diameter at right-angles to that which includes the rings and the thermometer as indicated in Figure 1 a) and Figure 1 b). Heat so that the temperature is raised by5 C eac

37、h minute. Except for the first3min, it is essential to maintain this heating rate to within 0,5 C over each1min period. It is essential that this rate should not be merely the average over the period of the test. Reject any results in which the heating rate does not conform to these requirements. Re

38、cord the temperature at which the pitch surrounding each ball first touches the lower plate of the support. If, for the two balls, this temperature differs by more than1 C, reject the results and repeat the test. If the test is repeated for any reason, carry out the whole procedure using a new test

39、portion. NOTEAt about85 C, slightly higher results are obtained when using glycerol than when using water. 7 Expression of results 7.1 Method of calculation The softening point is given by the mean of the two temperatures recorded as described in6.3. Express the result to the nearest0,2 C. 7.2 Preci

40、sion For pitches having melting points less than85 C: repeatability = 0,5 C reproducibility = 2,5 C For pitches having melting points greater than85 C: repeatability = 1,5 C reproducibility = 3,0 C 8 Test report The test report shall include the following particulars: a) an identification of the sam

41、ple; b) the reference of the method used, stating whether glycerol or water was used as the heating medium; c) the results and the method of expression used; d) any unusual features noted during the determination; e) any operations not included in this International Standard, or in the International

42、 Standard to which reference is made, or regarded as optional.BS6043-1.3:1983 BSI 10-1999 3 Annex A Details of thermometers Annex B Melting of pitch samples B.0 Introduction Prior to determining the softening point of pitch, it is necessary to melt the sample. The precision of the determination, and

43、 particularly its reproducibility, is considerably influenced by the homogeneity of the molten sample and its freedom from air bubbles. The procedure specified in this annex is designed to minimize variations in test results by standardizing the temperature and heating time. B.1 Apparatus B.1.1 Dish

44、, 55mm diameter, 35mm deep. Dishes sold for use with penetrometers are suitable. B.1.2 Oven, capable of being maintained at50 C above the expected softening point of the sample. B.2 Procedure Weigh approximately50g of the laboratory sample, powdered if its softening point permits, into the dish(B.1.

45、1) and place it in the oven (B.1.2) set at a temperature of50 C above the expected softening point of the pitch. Also place the rings (5.1.1) in the oven. Maintain the pitch and the rings at this temperature for2h and then use the heated rings and the molten pitch to prepare the test piece as descri

46、bed in6.1. NOTEAfter heating, the surface of the molten pitch should be smooth, shiny and free of skin. If the surface of the molten pitch is covered with froth, suggesting the presence of water, discard it and prepare another melt using a further50g of the laboratory sample, powdered if its softeni

47、ng point permits, which has been dried by allowing it to stand in an evacuated desiccator in the presence of a suitable desiccant. Range 0 to 120 C 50 to 210 C Graduation 0,5 C 0,5 C Immersion 100 mm 100 mm Longer lines at each a 1 and 5 C 1 and 5 C Fully figured at each 10 C 10 C Maximum overall le

48、ngth 430 mm 430 mm Minimum length of main scale 240 mm 240 mm Maximum error 0,6 C 0,8 C a The lines corresponding to each5 C shall be slightly longer than those corresponding to each1 C.BS6043-1.3:1983 4 BSI 10-1999 Figure 1 Assembled apparatus NOTEBall centring guides have been omitted for clarity.

49、BS6043-1.3:1983 BSI 10-1999 5 Dimensions in millimetres Figure 2 Tapered ring Dimensions in millimetres Figure 3 Recommended form of ball centring guideBS6043-1.3:1983 6 BSI 10-1999 Dimensions in millimetres Figure 4 Support for rings Dimensions in millimetres Figure 5 Plate for mouldingBS6043-1.3:1983 BSI 10-1999 Publications referred to See national foreword.BS 6043-1.3: 1983 ISO 5940:1981 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution