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1、BRITISH STANDARD BS ISO 5940-2:2007 Carbonaceous materials used in the production of aluminium Pitch for electrodes Part 2: Determination of the softening point (Mettler softening point method) ICS 71.100.10 ? Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:1
2、6:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS ISO 5940-2:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 June 2007 BSI 2007 ISBN 978 0 580 52906 1 National foreword This British Standard was published by BSI. It is the UK impleme
3、ntation of ISO 5940-2:2007. The UK participation in its preparation was entrusted to Technical Committee CII/24, Raw materials for the aluminium industry. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include a
4、ll the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank Uni
5、versity, Sun Jun 17 07:16:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI Reference number ISO 5940-2:2007(E) INTERNATIONAL STANDARD ISO 5940-2 First edition 2007-05-01 Carbonaceous materials used in the production of aluminium Pitch for electrodes Part 2: Determination of the softening point (Mettler
6、 softening point method) Produits carbons utiliss pour la production de laluminium Brai pour lectrodes Partie 2: Dtermination du point de ramollissement (Point de ramollissement par la mthode Mettler) BS ISO 5940-2:2007 Licensed Copy: London South Bank University, London South Bank University, Sun J
7、un 17 07:16:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ii Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of na
8、tional 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. Intern
9、ational 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. International Standards are drafted in accordance with the
10、rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by
11、at least 75 % of the member bodies casting a vote. 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. ISO 5940-2 was prepared by Technical Committee ISO
12、/TC 226, Materials for the production of primary aluminium. ISO 5940 consists of the following parts, under the general title Carbonaceous materials used in the production of aluminium Pitch for electrodes: Part 1: Determination of the softening point by the ring-and-ball method (will replace ISO 59
13、40:1981) Part 2: Determination of the softening point (Mettler softening point method) BS ISO 5940-2:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI iv Introduction This part of ISO 5940 is based on DIN 51
14、920 Testing of carbonaceous materials Determination of the Mettler softening point Binding and impregnating materials, prepared by NMP 281 “Prfverfahren fr Kohlenstoff und Graphit“ and published by DIN, Deutsches Institut fr Normung e.V., Berlin. Coal-tar pitch is used as a binding and impregnating
15、agent in the production of carbon anodes for primary aluminium metal production. When heated, pitch transforms gradually from a solid to a liquid. The analytical determination of a softening point described in this method is useful for characterizing this thermal behaviour of the coal-tar pitch when
16、 used as binder. The softening point is expressed as a temperature, in degrees Celsius (C). Annex A gives an approximate comparison with softening points determined by other methods. BS ISO 5940-2:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:12 GMT
17、+00:00 2007, Uncontrolled Copy, (c) BSI 1 Carbonaceous materials used in the production of aluminium Pitch for electrodes Part 2: Determination of the softening point (Mettler softening point method) 1 Scope This part of ISO 5940 specifies a method to determine the softening point of pitches by the
18、Mettler method, within the range of 50 C to 180 C. It can be used for other organic materials that are used as binder and impregnating agents, where they have a Mettler softening point within the range of 50 C to 150 C. 2 Normative references The following referenced documents are indispensable for
19、the application 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 6257, Carbonaceous materials used in the production of aluminium Pitch for electrodes Sampling DIN 133
20、3, Presentation of numerical data DIN 51848-1, Testing of mineral oils Precision General introduction, definitions and application to specifications 3 Principle A test portion of pitch is placed within a cylindrical sample cup with an outlet diameter of 6,35 mm. The temperature is increased under co
21、nstant conditions in air, until softened material issues from the outlet and interrupts a light barrier 19 mm below. BS ISO 5940-2:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 2 4 Apparatus and reagents
22、 4.1 Test apparatus1) (see Figure 1) consisting of the parts given in 4.1.1 to 4.1.7. 4.1.1 Electrically heated furnace. 4.1.2 Sample cup (see Figure 2), made from chrome-plated yellow brass or chrome nickel-steel. 4.1.3 Resistance thermometer, capable of measuring temperatures from 50 C to 180 C. 4
23、.1.4 Cup holder. 4.1.5 Light barrier, capable of sensing the material as it issues from the sample cup. 4.1.6 Control unit, with a temperature indicator for the thermometer (4.1.3), and an indicator to show the operational status of the machine. 4.1.7 Collector, for the softened material. 4.2 Bowl,
24、made of porcelain, Teflon or metal with a volume of about 50 ml. 4.3 Plate, with a smooth surface, e.g. made of metal or glass. 4.4 Knife or spatula. 4.5 Release agent for cup, e.g. a mixture of glycerine and dextrin, ratio 1:1. 4.6 Electro-hydraulic press, as described in ASTM D3104, or another sui
25、table press for filling the sample cup with grindable binder. 4.7 Punch, suitable for pressing grindable pitch. 4.8 Balance, capable of weighing grindable pitch to an accuracy of 0,1 g. 1) Available from Mettler Toledo Inc. http:/. Further information on sources of supply can be obtained from: DIN-B
26、ezugsquellen fr normgerechte Erzeugnisse of DIN Deutsches Institut fr Normung e. V., Burggrafenstrae 6, D-1000 Berlin 30. This information is given for the convenience of users of this part of ISO 5940 and does not constitute an endorsement by ISO of this apparatus. BS ISO 5940-2:2007 Licensed Copy:
27、 London South Bank University, London South Bank University, Sun Jun 17 07:16:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 3 Key 1 electrically heated furnace 2 sample cup 3 resistance thermometer 4 cup holder 5 light barrier 6 control unit with temperature indicator Figure 1 Schematic picture of t
28、he testing apparatus BS ISO 5940-2:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 4 Dimensions in millimetres Figure 2 Sample cup 5 Sampling Take a sample of the material in accordance with ISO 6257. 6 Sa
29、mple preparation 6.1 Types of material Pitch can be grindable or non-grindable. Prepare non-grindable pitch by melting (see 6.2) and grindable pitch by melting or pressing (see 6.3). 6.2 Preparation of pitch by melting Melt a test sample of about 20 g of the air-dry sample into the bowl (4.2), takin
30、g care to ensure that no overheating occurs at the wall of the vessel, and that no vapours pass off: Do not heat any part of the test portion of the sample to a temperature higher than 50 C above the expected softening point. Remove air bubbles from the melt by carefully stirring, and remove any foa
31、m developing on the surface of the melt. Foam is an indication of water in the pitch. Keep the sample at the same temperature until foaming ends. Prepare the surface of the plate (4.3) by rubbing the release agent (4.5) onto the surface of the plate. Place the sample cup (4.1.2) onto the prepared su
32、rface of the plate. Take the bowl and molten test sample (6.1) and fill the sample cup by pouring the molten material from the bowl into the cup, such that it protrudes above the top of the sample cup by 1 mm to 2 mm. After cooling, level the sample surface with the warmed knife or spatula to become
33、 flush with the upper rim of the sample cup. Take care to avoid hollow spaces in the sample: do not simply cut away the protruding part of the sample. Remove the cup from the plate. BS ISO 5940-2:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:12 GMT+
34、00:00 2007, Uncontrolled Copy, (c) BSI 5 6.3 Preparation of pitch by pressing Grind the sample so that the particle fraction ranges from 1 mm to 2 mm. Insert the sample cup in the cartridge assembly and fill the cup with ground material, use the punch to press the material in the cup slightly by han
35、d, then insert the cartridge assembly in the hydraulic mould. Apply a force of 15 kN to the sample in the cup for at least 15 s. Remove the assembly from the mould; and loosen the sample cup by tapping the head of the punch. Be aware that the temperatures at the measured softening points are lower b
36、y up to 1 C, when using this procedure. 7 Procedure 7.1 Placing the sample in the apparatus Assemble the filled sample cup with the sample cup holder and the collector sleeve to make a cartridge. 7.2 Operating the testing apparatus and expression of results Choose a temperature 20 C to 25 C below th
37、e expected softening point as a starting temperature. Adjust the equipment to a heating rate of 2 C per min. As soon as it is indicated that the apparatus is ready for operation, place the cartridge with the sample into the furnace and rotate until the collector sleeve is engaged. About 30 s later s
38、tart the apparatus. At the end of the determination, the Mettler softening point is read from the storage of results on the apparatus, in degrees Celsius, to the nearest 0,1 C. Rounding to the last significant decimal place shall be done in accordance with DIN 1333. 7.3 Calibrating the temperature 7
39、.3.1 Using a thermometer or thermocouple The temperature indication at the operating unit can be verified as follows: The ball of a suitable thermometer or the tip of a thermocouple is put into the sample cup and cast with pitch. Then the lower part of the sample holder, with the sample cup and ther
40、mometer or thermocouple, is put into the furnace and heated to a definite temperature. 5 min after the selected temperature is reached, the reading of the suitable thermometer or thermocouple shall be not more than 0,5 C below the reading of the resistance thermometer (4.1.3) on the control unit. Af
41、ter a longer duration, the difference of the readings should approach zero. If the furnace is heated with a constant temperature rate of 2 C/min (as in the procedure for determining the softening point), the suitable thermometer or thermocouple can be expected to indicate a temperature 1 C to 1,5 C
42、less than the control unit. 7.3.2 Using benzoic acid on units with a calibration program This test can be run every quarter or half year, or after adjustments. Place the test-portion holder on an even surface and fill with benzoic acid. Pack firmly using a 10 mm diameter glass rod. Select the calibr
43、ation program and run the analysis, but with a start temperature of 121 C and a temperature increase of 0,2 C/min. The results should be 123,5 0,5 C. If not, the apparatus must be adjusted. NOTE Pitch on the outside of the sample cup or inside the furnace will fume during the measurement and the fum
44、es can disturb the photocell. This can cause a measurement result that is too low. BS ISO 5940-2:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 6 8 Test report The test report shall include the following
45、information: a) a reference to this part of ISO 5940; b) any agreed deviations from this part of ISO 5940; c) the date of the test; d) details necessary for the complete identification of the material tested; e) type of material tested, e.g. grindable pitch or non-grindable pitch; f) whether the sam
46、ple was pressed, or poured in the melted state into the cup; g) the type of Mettler apparatus used and its manufacturer; h) the number of test specimens; i) the individual values and the mean value, in degrees Celsius, for the Mettler softening point, as indicated by the digital readout, to the near
47、est 0,1 C. 9 Precision 9.1 Determination The precision was determined in accordance with DIN 51848-1. 9.2 Repeatability The difference between two results, collected on the same sample by the same person with the same instrument under constant analysis conditions, is regarded as acceptable, and in c
48、onformity with this part of ISO 5940, if the difference is not larger than 0,5 C. 9.3 Reproducibility The difference between two single and independent results, collected on identical samples by different persons in different laboratories, is regarded as acceptable, and in conformity with this part
49、of ISO 5940, if they differ by not more than 1,5 C. BS ISO 5940-2:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:12 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 7 Annex A (informative) Approximate comparison with softening points determined by other methods The Mettler softening point (MSP) can be compared approximately with softening points obtained by other methods by applying the fo