BS 6043-3 8 1-2001 Methods of sampling and test for carbonaceous materials used in aluminium manufacture - Electrodes - Carboxy reactivity of prebaked anodes - Determination of the.pdf

1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 6043-3.8.1:2001 ISO 12

2、988-1:2000 ICS 71.100.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Methods of sampling and test for carbonaceous materials used in aluminium manufacture Part 3: Electrodes Section 3.8: Carboxy reactivity of prebaked anodes Subsection 3.8.1: Determination of the reactivit

3、y by a loss in mass methodThis British Standard, having been prepared under the direction of the Sector Committee for Materials and Chemicals, was published under the authority of the Standards Committee and comes into effect on 15 March 2001 BSI 03-2001 ISBN 0 580 36966 8 BS 6043-3.8.1:2001 Amendme

4、nts issued since publication Amd. No. Date Comments National foreword This British Standard reproduces verbatim ISO 12988-1:2000 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee CII/24, Raw materials for the aluminium industr

5、y, which has the responsibility 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 promulga

6、te them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled

7、“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 for their correct application. Compliance w

8、ith 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, the ISO title page, pages ii to iv, pages 1 to 9 and a back cover. The BSI copyright notice displayed in this document indicates when the d

9、ocument was last issued.Reference number ISO 12988-1:2000(E) INTERNATIONAL STANDARD ISO 12988-1 First edition 2000-05-01 Carbonaceous materials used in the production of aluminium Baked anodes Determination of the reactivity to carbon dioxide Part 1: Loss in mass method Produits carbons utiliss pour

10、 la production de laluminium Anodes cuites Dtermination de la ractivit au dioxyde de carbone Partie 1: Mthode par perte de masse BS60433.8.1:2001ii BS60433.8.1:2001iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member

11、 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, governmental

12、 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 rules given in the ISO/IEC Directiv

13、es, Part 3. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elemen

14、ts of this part of ISO 12988 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 12988-1 was prepared by Technical Committee ISO/TC 47, Chemistry, Subcommittee SC 7, Aluminium oxide, cryolite, aluminium fluo

15、ride, sodium fluoride, carbonaceous products for the aluminium industry. ISO 12988 consists of the following parts, under the general title Carbonaceous materials used in the production of aluminium Baked anodes Determination of the reactivity to carbon dioxide: Part 1: Loss in mass method A thermog

16、ravimetric method will be the subject of a future part 2 to ISO 12988. BS60433.8.1:2001iv Introduction Carbon reacts with carbon dioxide according to the following equation: CC O 2 C O 2 The loss of anode material from reaction with CO 2 under certain constant conditions, as well as the mass of the

17、remaining specimen and of the dust resulting from selective burning, are of importance in predicting the behaviour of the anodes in the electrolysis cell. BS60433.8.1:2001INTENRATIONAL TSANDADR ISO -889211:(0002E) 1 Carbonaceous materials used in the production of aluminium Baked anodes Determinatio

18、n of the reactivity to carbon dioxide Part 1: Loss in mass method 1 Scope This part of ISO 12988 specifies a loss in mass method for the determination of the reactivity of carbonaceous products to carbon dioxide. This method was developed especially for baked anodes used in the production of alumini

19、um. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of ISO 12988. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreeme

20、nts based on this part of ISO 12988 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of cu

21、rrently valid International Standards. ISO 8007-2:1999, Carbonaceous materials used in the production of aluminium Sampling plans and sampling from individual units Part 2: Prebaked anodes. IEC 60584-2, Thermocouples Part 2: Tolerances. 3P r i n c i p l e A baked test cylinder is placed in a furnace

22、 purged with carbon dioxide, CO 2 , at a temperature of 960 C for 7 h. The loss in mass is determined and the dust produced is measured using a tumbling-apparatus. The residual body of the test cylinder, called the unreacted residue, is weighed and all results calculated in mass percent. 4 Reagent 4

23、.1 Carbon dioxide,(CO 2 ) having a minimum purity of 99,5 % by volume and impurities of N 2 Ar 0,5 % by volume, H 2 O 150 mg/m 3 . BS60433.8.1:20012 5 Apparatus A diagram showing a typical apparatus in accordance with specifications is shown in Figure 1. Normal ordinary apparatus and in particular t

24、he following: 5.1 Muffle furnace, having the dimensions given in Figure 2 with a vertical, single-zone tube ensuring good, vertical temperature distribution and capable of heating to a maximum temperature of at least 1 000 C as well as maintaining the temperature at (960 2) C. 5.2 Sample holder, mad

25、e of heat-resistant steel to support the two test specimens in the centre of the furnace with a collection plate incorporated for catching dust falling from the specimens. An appropriate test arrangement is shown in Figure 3. 5.3 Temperature controller, consisting of a two-point temperature PID cont

26、roller with a set value adjuster (adjustment error 0,5 %) and with a digital temperature display. 5.4 Gas-flow meter and pressure control, consisting of a gas-flow meter calibrated for CO 2 gas and a manometer. The CO 2 gas-flow meter (p = 0,1 MPa) having a full-scale flow rate of 250 l/h, shall be

27、accurate to 4 %. The gas pressure is adjusted using a valve to obtain the regular value, 0,2 MPa, which shall be controlled by a manometer. The full scale of the manometer shall be 0 MPa to 1 MPa. It shall be capable of introducing CO 2 into the muffle furnace and of keeping the gas-flow constant by

28、 less than 3 % for the duration of the test. 5.5 Thermocouple, chromel-alumel, K-type, accurate to better than 0,75 % in accordance with IEC 60584-2, having a 2,8 mm diameter with a minimum length of 400 mm. The distance between the upper surface of the anode and the thermocouple shield shall be (10

29、 0,5) mm. 5.6 Alumina tube, covering the gas inlet tube (see Figure 1) at the bottom of the furnace and for preheating the gas. 5.7 Tumbling-apparatus, having the following components and assembled as shown in Figure 4. 5.7.1 Electric motor, 90 r/min, 220 V or 110 V, 50/60 Hz. 5.7.2 Two steel cylind

30、rical chambers, with the following dimensions: internal diameter: 68 mm; internal height: 120 mm. 5.7.3 50 steel balls, per chamber (5.7.2), of approximately 6 mm diameter. 5.7.4 Sieve, of 4 mm aperture and pan. BS60433.8.1:20013 Key 1 Thermocouple 2 Test specimen 3 Preheater with alumina tube Figur

31、e 1 Schema of apparatus assembly BS60433.8.1:20014 Dimensions in millimetres Figure 2 Dimensions of typical muffle furnace BS60433.8.1:20015 Dimensions in millimetres Figure 3 Example of an arrangement for the determination of the reactivity of the anodes to CO 2 BS60433.8.1:20016 Dimensions in mill

32、imetres Key 1 Chamber 2 Motor 3S i e v e Figure 4 Tumbling-apparatus for determining the amount of dust produced BS60433.8.1:20017 6 Sampling When the test specimens (or cores) are to be extracted from a larger body, sampling shall be carried out in accordance with the procedure specified in ISO 800

33、7-2. Alternatively, samples may be prepared in the laboratory by a bench-scale procedure. 7 Preparation of test specimens Prepare two test specimens each with a core diameter of (50 1) mm and a length of (60 1) mm. Dry the specimens at (120 5) C for 12 h and cool to room temperature. 8 Procedure Det

34、ermine the initial mass of each test specimen by weighing each one (cores) (m 0 ) to 0,1 g. Heat the muffle furnace (5.1) to (960 2) C. Maintain the furnace at this temperature for at least 60 min to allow the temperature to stabilize, open the furnace, insert the test specimens and close the furnac

35、e. Start the gas flow of CO 2 and adjust the flow rate (see 5.4) through the alumina tube (5.6) to 200 l/h. Maintain the furnace at 960 C and the gas flow at 200 l/h for 7 h. After 7 h, switch off the furnace and after an additional 2 h cooling, switch off the gas flow. Once the temperature of the f

36、urnace falls below 550 C, remove the residual body of the test specimen and the dust produced. Allow the residual body of the test specimen (cores) and the dust to cool to room temperature and weigh them (m 1 ) to the nearest 0,1 g. Place each residual test specimen (core) in a separate chamber (5.7

37、.2) of the tumbling- apparatus with 50 steel balls (5.7.3) and allow them to tumble for 20 min to remove any loose particles. Once the tumbling has been completed, empty the chamber into the 4 mm sieve (5.7.4), remove the balls, then weigh the residual bodies of the test specimens (cores) to the nea

38、rest 0,1 g (m 2 ). 9 Expression of results Determine the reactivity-to-CO 2 parameters, w RC (residue, dust and loss), expressed as a percentage by mass, using the following formulae: Residue, w RCR : w RCR = m m 2 0 100 Dust, w RCD : w RCD = mm m 1 2 0 100 Loss, w RCL : w RCL = mm m 01 0 100 where

39、m 0 is the initial mass, expressed in grams, of the test specimen (core); m 1 is the mass, expressed in grams, of the residual test specimen (core) and dust; m 2 is the mass, expressed in grams, of the residual test specimen (core) after tumbling. Report the result to 0,1 g. BS60433.8.1:20018 10 Pre

40、cision 10.1 Repeatability The repeatability of the test depends strongly on the homogeneity of the tested cores and is therefore difficult to assess. 10.2 Reproducibility In 1993, samples were tested in over 20 laboratories which has allowed an estimate of the reproducibility, R,o ft h et e s t to b

41、e made (see Figure 5) as a function of the level of the reactivity-to-CO 2 . These reproducibility figures can be used when the average of at least 30 cores is determined to characterize a given electrode population. 11 Test report The test report shall include the following information: a) an ident

42、ification of the sample; b) the method used with reference to this part of ISO 12988, i.e. 12988-1:1999; c) the method of sample preparation. d) the date of the test; e) the results and the method of expression used; f) any unusual features noted during the determination; g) any operation not includ

43、ed in this part of ISO 12988 or in the International Standard or in the International Standards to which reference is made, or regarded as optional; BS60433.8.1:20019 a) Estimated reproducibility R RCR as a function of w RCR (reactivity-to-CO 2 parameter for residue) b) Estimated reproducibility R R

44、CD as a function of w RCD (reactivity-to-CO 2 parameter for dust) c) Estimated reproducibility R RCL as a function of w RCL (reactivity-to-CO 2 parameter for loss) Figure 5 Estimated reproducibility, R RC , as a function of the reactivity-to-CO 2 parameter, w RC BS60433.8.1:2001BS 6043-3.8.1:2001 IS

45、O 12988-1:2000 BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

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