ISO 12989-1-2000 Carbonaceous materials used in the production of aluminium - Baked anodes and sidewall blocks - Determination of the reactivity to air - Part 1.pdf

1、Reference number ISO 12989-1:2000(E) ISO 2000 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 pr

2、oduction de laluminium Anodes et blocs de faade cuits Dtermination de la ractivit lair Partie 1: Mthode par perte de masseISO 12989-1:2000(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or viewed but shall not be e

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6、nical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 734 10 79 E-mail copyrightiso.ch Web www.iso.

7、ch Printed in Switzerland ii ISO 2000 All rights reservedISO 12989-1:2000(E) ISO 2000 All rights reserved iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is

8、 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 liaison with ISO, also take part

9、 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 International Standards adopted by the t

10、echnical 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 12989 may be the subject of patent

11、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, carbonaceous products for the aluminium i

12、ndustry. 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 will be the subject of a future par

13、t 2 to ISO 12989.ISO 12989-1:2000(E) iv ISO 2000 All rights reserved 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 predi

14、cting the behaviour of the anodes during the aluminium reduction process.INTERNATIONAL STANDARD ISO 12989-1:2000(E) ISO 2000 All rights reserved 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 m

15、ethod 1 Scope 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 provision

16、s which, through 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 possibil

17、ity 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 currently valid International Standards. ISO 8007-2:1999, Carbonaceous materials

18、 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 cylinder is first heated to 550 C and then cooled with a gradient of 15 C/h to (400 1) C. Frequent agitation is necessar

19、y so that 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

20、4.1 Air, bottled or compressed, containing less than 100 g/g of free water.ISO 12989-1:2000(E) 2 ISO 2000 All rights reserved 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 dimensio

21、ns 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 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 Sam

22、ple holder, to support the carbon block in 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 integr

23、ated digital controller, capable of easily 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 mano

24、meter. The gas-flow meter shall have a full-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 t

25、o better than 0,75 % in accordance with IEC 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

26、 5.7.1 Electric motor, 90 r/min, 220 V or 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.ISO 12989

27、1:2000(E) ISO 2000 All rights reserved 3 Dimensions in millimetres Key 1 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 airISO 129

28、89-1:2000(E) 4 ISO 2000 All rights reserved Dimensions in millimetres Figure 2 Dimensions of typical muffle furnaceISO 12989-1:2000(E) ISO 2000 All rights reserved 5 Key a Temperature controller on b Sample in c Air flowing d Switch off air e Remove sample Figure 3 Temperature profile and gas operat

29、ions 6 Sampling When the test specimen (or core) is to be extracted from a larger body, sampling shall be carried out in accordance with the 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

30、 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 temperature. 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 mi

31、nus depth of hole). A hard-metal drill bit (diameter 7 mm), with a tip angle of 140 is recommended.ISO 12989-1:2000(E) 6 ISO 2000 All rights reserved Dimensions in millimetres Key 1 Chamber 2 Motor 3 Sieve Figure 4 Tumbling-apparatus for determining the amount of dust producedISO 12989-1:2000(E) ISO

32、 2000 All rights reserved 7 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 and the cooling rate shall be 15 C/h. 8.2 Weigh the initial sample (m 0 ) to the nearest 0,1 g and

33、 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) flowing through the pre-heater (see Figure 1). Set the gas pressure of the air to 0,2 MPa and adjust th

34、e 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 the dust from the aluminium plate. Allow the test specimen to cool to room temperature. 8.4 Weigh

35、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 chamber (5.7.2) into the 4 mm sieve (5.7.4) and remove the balls (5.7.3). Weigh the residual body of t

36、he 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, 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

37、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 grams, of the residual test specimen (core) after tumbling. Report the result to 0,1 g. 10 Precision 1

38、0.1 Repeatability The repeatability of the test depends strongly on the homogeneity of the tested cores and is therefore difficult to assess.ISO 12989-1:2000(E) 8 ISO 2000 All rights reserved 10.2 Reproducibility An inter-laboratory trial has allowed an estimate of the reproducibility, R, of the tes

39、t 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 report shall include the following information: a) an identification o

40、f 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 determination; g) any operation not included in this part of ISO

41、12989 or in the International Standards to which reference is made, or regarded as optional.ISO 12989-1:2000(E) ISO 2000 All rights reserved 9 a) Estimated reproducibility R RAR as a function of w RAR (reactivity-to-air parameter for residue) b) Estimated reproducibility R RAD a safu nc ti ono fw RA

42、D (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 RAISO 12989-1:2000(E) ICS 71.100.10 Price based on 9 pages ISO 2000 All rights reserved