BS 6043-3 9 1-2002 Methods of sampling and test for carbonaceous materials used in aluminium manufacture - Electrodes - Chemical reactivity to air of prebaked anodes - Determinatio.pdf

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1、BRITISH STANDARD BS 6043-3.9.1: 2002 ISO 12989-1:2000 Methods of sampling and test for carbonaceous materials used in aluminium manufacture Part 3.9.1: Electrodes Chemical reactivity to air of prebaked anodes Determination of the reactivity by a loss in mass method ICS 71.100.10 BS 6043-3.9.1:2002 T

2、his British Standard, having been prepared under the direction of the Material and Chemicals Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 23 September 2002 BSI 23 September 2002 ISBN 0 580 40378 5 National foreword This Bri

3、tish Standard reproduces verbatim ISO 12989-1:2000 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 industry, which has the responsibility to: A list of organizations represented on thi

4、s 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 Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search

5、” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obli

6、gations. 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. Summary

7、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 date displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsReference

8、 number ISO 12989-1:2000(E) INTERNATIONAL STANDARD ISO 12989-1 First edition 2000-05-01 Carbonaceous materials used in the production of aluminium Baked anodes and sidewall blocks Determination of the reactivity to air Part 1: Loss in mass method Produits carbons utiliss pour la production de lalumi

9、nium Anodes et blocs de faade cuits Dtermination de la ractivit lair Partie 1: Mthode par perte de masse BS60433.9.1:2002ii BS60433.9.1:2002iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of pr

10、eparing 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, i

11、n 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 Directives, Part 3. Draft Intern

12、ational 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 elements of this part of ISO 1

13、2989 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 12989-1 was prepared by Technical Committee ISO/TC 47, Chemistry, Subcommittee SC 7, Aluminium, cryolite, aluminium fluoride, sodium fluoride, carbona

14、ceous products for the aluminium industry. ISO 12989 consists of the following parts, under the general title Carbonaceous materials used in the production of aluminium Baked anodes and sidewall blocks Determination of the reactivity to air: Part 1: Loss in mass method The thermogravimetric method w

15、ill be the subject of a future part 2 to ISO 12989. BS60433.9.1:2002iv Introduction The combustion of carbonaceous materials in air leads to undesirable losses that should be minimized in many industrial processes. The loss of carbonaceous anode material from burning with air is of importance in pre

16、dicting the behaviour of the anodes during the aluminium reduction process. BS60433.9.1:2002INTENRATIONAL TSANDADR ISO -989211:(0002E) 1 Carbonaceous materials used in the production of aluminium Baked anodes and sidewall blocks Determination of the reactivity to air Part 1: Loss in mass method 1 Sc

17、ope This part of ISO 12989 specifies a loss-in-mass method for the determination of the reactivity of carbonaceous products to air. The method was developed especially for anodes used in the production of aluminium. 2 Normative references The following normative documents contain provisions which, t

18、hrough reference in this text, constitute provisions of this part of ISO 12989. For dated references, subsequent amendments to, or revisions of, any of these publications do not apply. However, parties to agreements based on this part of ISO 12989 are encouraged to investigate the possibility of app

19、lying 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 currently valid International Standards. ISO 8007-2:1999, Carbonaceous materials used in t

20、he 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 cylinder is first heated to 550 C and then cooled with a gradient of 15 C/h to (400 1) C. Frequent agitation is necessary so that

21、the carbon dust caused by the selective burning of the binder matrix can be collected outside the furnace. Loose particles on the sample are removed using a tumbling-apparatus. The reactivity residue, being the residual body, and the reactivity loss due to burning are reported. 4 Reagents 4.1 Air, b

22、ottled or compressed, containing less than 100 g/g of free water. BS60433.9.1:20022 5 Apparatus An appropriate test-apparatus arrangement is shown in Figure 1. Normal ordinary apparatus and in particular the following: 5.1 Muffle furnace, having the dimensions given in Figure 2 with a vertical, sing

23、le-zone tube ensuring good, vertical temperature distribution and capable of heating to a maximum temperature of at least 700 C. The tube shall be made in a refractory steel (austenite) and have an internal diameter of 88,6 mm and a length of 486 mm. 5.2 Sample holder, to support the carbon block in

24、 the centre of the furnace with a collection plate incorporated for catching dust falling from the specimens. 5.3 Cam mechanism, motor-driven, which agitates the sample each minute (5 mm fall, 1 r/min). 5.4 Programmable temperature controller, with an integrated digital controller, capable of easily

25、 generating and controlling the desired temperature profile (see Figure 3). At least four relays are necessary for the gas and furnace operations. 5.5 Gas-flow meter and pressure control, consisting of a gas-flow meter calibrated for air (p =0,1MPa)anda manometer. The gas-flow meter shall have a ful

26、l-scale flow rate of 250 l/h and shall be accurate to 4 %. The gas pressure is adjusted using a valve and the required value, 0,2 MPa, can be controlled by a manometer having a full sca l eo f0MP ato1MPa . 5.6 Thermocouple, chromel-alumel, K-type, accurate to better than 0,75 % in accordance with IE

27、C 60584-2, 1,6 mm diameter and having a minimum length of 340 mm. The distance between the upper surface of the anode and the thermocouple shield shall be (10 1,0) mm. 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

28、 110 V, 50/60 Hz. 5.7.2 Two steel cylindrical chambers, with the following dimensions: internal diameter: 69 mm internal height: 120 mm 5.7.3 50 steel balls, per chamber (5.8.2), of approximately 6 mm diameter. 5.7.4 Sieve, of 4 mm aperture and pan. BS60433.9.1:20023 Dimensions in millimetres Key 1

29、Thermocouple 2A i r 3 Air preheater 4 Muffle furnace 5 Carbon block test specimen 6 Sample holder 7D u s t 8 Cam mechanism Figure 1 Test-apparatus arrangement for the determination of the reactivity of the anodes to air BS60433.9.1:20024 Dimensions in millimetres Figure 2 Dimensions of typical muffl

30、e furnace BS60433.9.1:20025 Key a Temperature controller on b Sample in c Air flowing d Switch off air e Remove sample Figure 3 Temperature profile and gas operations 6 Sampling When the test specimen (or core) is to be extracted from a larger body, sampling shall be carried out in accordance with t

31、he procedure specified in ISO 8007-2. Alternatively, samples may be prepared in the laboratory, by a bench scale procedure. 7 Preparation of test specimen Prepare a test specimen with a core diameter of (50 1) mm and a length of (60 1) mm. Dry the specimen at (120 5) C for 12 h and cool to room temp

32、erature. Drill a hole of 7 mm diameter in the bottom centre of the cylinder to a depth of (30 0,5) mm measured from the top of the cylinder (height of cylinder minus depth of hole). A hard-metal drill bit (diameter 7 mm), with a tip angle of 140 is recommended. BS60433.9.1:20026 Dimensions in millim

33、etres Key 1 Chamber 2 Motor 3 Sieve Figure 4 Tumbling-apparatus for determining the amount of dust produced BS60433.9.1:20027 8 Procedure 8.1 Program the temperature controller (5.4) according to the profile illustrated in Figure 3 and as specified in 8.3. The temperature shall not exceed (550 1) C

34、and the cooling rate shall be 15 C/h. 8.2 Weigh the initial sample (m 0 ) to the nearest 0,1 g and record the mass. 8.3 Start the temperature controller. Raise the temperature of the muffle furnace (5.1) to 550 C. Place the test specimen (core) in the furnace. After 30 min, start the air (4.1) flowi

35、ng through the pre-heater (see Figure 1). Set the gas pressure of the air to 0,2 MPa and adjust the flow meter valve so as to have a flow rate of 200 l/h. After 10 h, when the temperature of (400 1) C is reached, switch off the air. Remove the cylinder when the furnace has reached 300 C and collect

36、the dust from the aluminium plate. Allow the test specimen to cool to room temperature. 8.4 Weigh each test specimen (core) with its associated dust (m 1 ) to the nearest 0,1 g. Place the test specimen (core) into the tumbling-apparatus chamber (5.7) and allow it to tumble for 20 min. Empty the cham

37、ber (5.7.2) into the 4 mm sieve (5.7.4) and remove the balls (5.7.3). Weigh the residual body of the test specimen (core) (m 2 )t ot he nearest 0,1 g. 9 Calculation The reactivity-to-air parameters, w RA (residue, dust and loss), expressed as a percentage by mass, are given by the formulae : Residue

38、, w RAR : w RAR = m m 2 0 100 Dust, w RAD : w RAD = mm m 12 0 100 Loss, w RAL : w RAL = mm m 01 0 100 where 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 gram

39、s, of the residual test specimen (core) after tumbling. Report the result to 0,1 g. 10 Precision 10.1 Repeatability The repeatability of the test depends strongly on the homogeneity of the tested cores and is therefore difficult to assess. BS60433.9.1:20028 10.2 Reproducibility An inter-laboratory t

40、rial has allowed an estimate of the reproducibility, R, of the test to be made as a function of the reactivity-to-air (see Figure 5). These reproducibility figures can be used when at least 30 cores are used for determination to characterize a given electrode population. 11 Test report The test repo

41、rt shall include the following information: a) an identification of the sample; b) the method used by reference to this part of ISO 12989, i.e. 12989-1; c) the method of sampling used; d) the date of the test; e) the results and the method of expression used; f) any unusual features noted during the

42、 determination; g) any operation not included in this part of ISO 12989 or in the International Standards to which reference is made, or regarded as optional. BS60433.9.1:20029 a) Estimated reproducibility R RAR as a function of w RAR (reactivity-to-air parameter for residue) b) Estimated reproducib

43、ility R RAD a safu nc ti ono fw RAD (reactivity-to-air parameter for dust) c) Estimated reproducibility R RAL as a function of w RAL (reactivity-to-air parameter for loss) Figure 5 Estimated reproducibility, R RA , as a function of the reactivity-to-air parameter, w RA BS60433.9.1:2002BS 6043-3.9.1:

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