ISO 12982-1-2000 Carbonaceous materials used in the production of aluminium - Calcined coke Determination of the reactivity to air - Part 1 Ignition temperature.pdf

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1、INTERNATIONAL STANDARD ISO 12982-1 First edition 2000-12-15 Reference number ISO 12982-1:2000(E) ISO 2000 Carbonaceous materials used in the production of aluminium Calcined coke Determination of the reactivity to air Part 1: Ignition temperature method Produits carbons utiliss pour la production de

2、 laluminium Coke ca l cin D termi na tio ndelar a ctiv itl ai r Partie 1: Mthode de la temprature dinflammabilitISO 12982-1:2000(E) ii ISO 2000 All rights reserved PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobes licensing policy, this file may be printed or vie

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5、for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2000 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any mean

6、s, elec- tronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISOs mem- ber 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 22 749 09 47 E-mail co

7、pyrightiso.ch Web www.iso.ch Printed in SwitzerlandISO 12982-1:2000(E) ISO 2000 All rights reserved iii Contents Page 1 Scope . 1 2 Normative references . 1 3 Principle 1 4 Reagents 1 5 Apparatus . 2 6 Sampling . 2 7 Preparation of test sample 5 8 Procedure . 6 9 Calculation and expression of result

8、s . 6 10 Precision . 7 11 Test report 7 Bibliography. 9ISO 12982-1:2000(E) iv ISO 2000 All rights reserved 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 no

9、rmally carried out through ISO technical com- mittees. 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 liai- son with ISO, also take par

10、t 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

11、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 12982 may be the subject of patent

12、 rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 12982-1 was prepared by Technical Committee ISO/TC 47, Chemistry, Subcommittee SC 7, Aluminium oxide, cryolite, aluminium fluoride, sodium fluoride, carbonaceous products for the alum

13、inium in- dustry. ISO 12982 consists of the following parts, under the general title Carbonaceous materials used in the production of aluminium Calcined coke Determination of the reactivity to air: Part 1: Ignition temperature method A thermogravimetric method will be the subject of a future part 2

14、to ISO 12982.INTERNATIONAL STANDARD ISO 12982-1:2000(E) ISO 2000 All rights reserved 1 Carbonaceous materials used in the production of aluminium Calcined coke Determination of the reactivity to air Part 1: Ignition temperature method 1 Scope This part of ISO 12982 describes an ignition temperature

15、method for the determination of the reactivity to air of cal- cined petroleum coke used in the manufacture of anodes for the production of aluminium. A heating rate of is used for petroleum coke specifications, whereas is used for statistical process control of calcination kilns and for anode butt q

16、uality control. NOTE ISO 12982-2 (in preparation) will give a thermobalance method for the determination of the reactivity to air of calcined coke. 2 Normative references The following normative documents contain provisions which, through reference in this text, constitute provisions of this part of

17、 ISO 12982. 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 12982 are encouraged to investigate the possibility of applying the most recent editions of the normative documents indicated

18、below. For undated references, the latest edition of the normative document referred to applies. Members of ISO and IEC maintain registers of cur- rently valid International Standards. ISO 6375, Carbonaceous materials for the production of aluminium Coke for electrodes Sampling. ISO 8723, Carbonaceo

19、us materials for the production of aluminium Calcined coke Determination of oil content Method by solvent extraction. ISO 12984, Carbonaceous materials used in the production of aluminium Calcined coke Determination of par- t icl es iz ed i st rib ut i on . 3 Principle The reactivity to air of calci

20、ned coke is measured by calculation after determining the ignition temperature of a sam- ple exposed to air, and thus oxygen. A coke sample of having a grain size of to is exposed to an air stream of in a furnace heated at or , depending on the sample history and the intended application. Ignition i

21、s assumed to oc- cur at the point where a sudden rise in the sample temperature occurs. The reactivity to air is calculated using a correlation derived from thermogravimetric measurements made on coke samples 12 . 4R e a g e n t s 4.1 Air, bottled or compressed, containing less than free water. 5 C/

22、min 10 C/min 5 g 1 mm 1,4 mm 50 l/h 10 C/min 0,5 C/min 100 mg/kgISO 12982-1:2000(E) 2 ISO 2000 All rights reserved 4.2 Certified calibration standard, having an ignition temperature of about at a heating rate of . 5 Apparatus Ordinary laboratory apparatus and the following. 5.1 Furnace, capable of h

23、eating from to in less than . A vertical, single-zone tube furnace that ensures a good vertical temperature distribution shall be used. A furnace having suitable dimensions is shown in Figure 1. 5.2 Tube reactor, consisting of two quartz tubes and a cap, with ground-glass joints, assembled as descri

24、bed in 5.2.1 to 5.2.4. NOTE A tube reactor having suitable dimensions for the furnace is shown in Figure 2 and a diagram of a complete apparatus is g iv e ni nF i gur e3. 5.2.1 External tube, consisting of the following: gas inlet, positioned near the top of the external tube, allowing gas to flow d

25、own to the bottom of the tube and to be preheated before flowing up through the coke bed; protection tube, for the thermocouple (5.3), positioned so that the tip of the thermocouple lies underneath the fritted disc (5.2.3). The gas inlet tube and the thermocouple protection tube shall extend outside

26、 the furnace. 5.2.2 Reaction tube, fitted inside the external tube (5.2.1). 5.2.3 Fritted disc,ha vingaporesiz eof to ,fittedinsidethereactiontubeandpositionedsothatthe base of the coke bed lies in the middle of the furnace. 5.2.4 Cap, containing a gas outlet, clamped to the top of the reaction tube

27、. 5.3 Thermocouple, chromel alumel, K-type, having an accuracy of better than , a diameter of and a minimum length of . 5.4 Progammable temperature control unit, consisting of a two-point temperature DPID controller with adjust- able heating rate and temperature display. 5.5 Chart recorder, to recor

28、d the temperature of the test sample versus time. Alternatively, a microprocessor which automatically detects the ignition temperature can be used. 5.6 Flow meter, with a calibrated scale for air ( ), having a full-scale reading of and an accuracy of better than . 5.7 Pressure control, comprising a

29、valve to regulate the pressure and a manometer having a scale reading from to . 6 Sampling Take a sample of the coke in accordance with the procedure specified in ISO 6375. 620 C1 0 C/min 20 C 1 000 C1 h 5mm 250 m 500 m 0,375 % 2 mm 200 mm p = 0,1 MPa 60 l/h 2% 0 MPa 1,0 MPaISO 12982-1:2000(E) ISO 2

30、000 All rights reserved 3 Dimensions in millimetres Figure 1 Characteristics and dimensions of a typical furnaceISO 12982-1:2000(E) 4 ISO 2000 All rights reserved Dimensions in millimetres Key 1 Air inlet 2A i r o u t l e t 3 Test sample Figure 2 Tube reactor with test sampleISO 12982-1:2000(E) ISO

31、2000 All rights reserved 5 7 Preparation of test sample Divide the sample into three fractions by sieving in accordance with ISO 12984. The fractions shall have the following dimensions: I IIa to III Crush fraction I to produce fraction IIb so that most of fraction IIb has the following dimensions a

32、fter sieving: IIb to Thoroughly mix fractions IIa and IIb. Key 1 Manometer 2 Chart recorder 3 Reactivity-to-air apparatus 4 Gas flow meter 5 Furnace 6P r e s s u r e v a l v e 7 Thermocouple Figure 3 Reactivity-to-air apparatus 1,4 mm 1 mm 1,4 mm 1mm 1 mm 1,4 mmISO 12982-1:2000(E) 6 ISO 2000 All rig

33、hts reserved Many granular materials are coated with oil. In such cases, remove the oil from the mixture of fractions IIa and IIb with dichloromethane, using the procedure specified in ISO 8723. Dry the mixture of fractions IIa and IIb at to constant mass, i.e. until consecutive weighings at i nt e

34、rv a lsd i f f e rb yl es st h an . Take a test sample of from the mixture of fractions IIa and IIb and weigh it to the nearest . 8 Procedure 8.1 Calibration Carry out two measurements on a calibration standard having an ignition temperature , and calculate the mean of the results, , in order to cal

35、ibrate the thermocouple which measures the sample temperature. Perform the calibration procedure once a week and after any maintenance of the apparatus (replacement of reactor tube or thermocouple, etc.). Calibrate the chart recorder periodically. Calculate the difference between the calibration sta

36、ndard reference temperature and the actual temperature deter- mined, ( ), which is subtracted from the values determined for test samples. 8.2 Determination Programme the temperature controller in accordance with Table 1 for the desired application. Switch on the furnace, insert the empty inner quar

37、tz tube and fix the cover with the clamp. Heat the furnace to the standby temperature. Open the air valve and regulate the pressure to and the flow rate to . When the furnace temperature has stabilized at the standby temperature ( ), insert the weighed test sample into the re- action tube and start

38、to increase the furnace temperature, plotting the temperature of the sample on the chart re- corder. When a sharp increase in the sample temperature occurs, stop the furnace and the gas flow. 9 Calculation and expression of results Determine the ignition temperature, , of the coke from the time-temp

39、erature plot by extending the two linear sec- tions of the curve (before and after ignition) towards the point at which the sharp increase in temperature occurs. Read off the ignition temperature as the point of intersection of the lines. Express the ignition temperature, , to the nearest . If a hea

40、ting rate of was used, calculate the reactivity to air at , , expressed as a percentage loss in mass per minute, using the equation or, if a heating rate of was used, calculate the reactivity to air at , , expressed as a percentage loss in mass per minute, using the equation Table 1 Temperature cont

41、roller programmes Application Fast method Slow method Standby temperature Temperature gradient (110 5) C 5 min 0,1 % (5 0,01) g 0,001 g T R T M T M T R 300 C 450 C 10 C/min 0,5 C/min 0,2 MPa 50 l/h 3 C T I T I 0,1 C 0,5 C/min 525 C ! 525 log ! 525 =9,519 4,159 10 2 T I + 6,158 10 6 T 2 I 10 C/min 60

42、0 C ! 600 ! 600 =50,064 + 75 364 T I 2,798 3 10 7 T 2 I ISO 12982-1:2000(E) ISO 2000 All rights reserved 7 where is the measured ignition temperature, in kelvins, for the heating rate used (for the derivation of these equa- tions, see references 1 and 2). Express the reactivity to air to the nearest

43、 . NOTE Alternatively, the above calculations may be carried out automatically by a microprocessor. 10 Precision 10.1 Repeatability The results of duplicate determinations, carried out in the same laboratory by the same operator with the same ap- paratus but at different times on representative test

44、 samples taken from the same laboratory sample, should not differ by more than the figures given in Table 2 for the “Fast method” ( ) and the figures given in Table 3 for the “Slow method” ( ). 10.2 Reproducibility The means of the results of duplicate determinations, carried out in each of two labo

45、ratories on representative test samples taken from the same sample after the last stage of sample preparation, should not differ by more than the figures given in Table 2 for the “Fast method” ( ) and the figures given in Table 3 for the “Slow method” () . Figures 4 and 5 show the precision as a fun

46、ction of the reactivity to air for each of the methods. 11 Test report The test report shall include the following information: a) complete identification of the sample tested; b) a reference to this part of ISO 12982, i.e. ISO 12982-1; c) thed ateofth ete stan dthere su lts ,e xp re sse dinac co rd

47、 an cewithcl au se9; d) any unusual features noted during the determination; e) any operation not included in this part of ISO 12982 or in the International Standards to which reference is made, or regarded as optional; f) the name and address of the certifying organization for the calibration stand

48、ard. Table 2 Fast method() Parameter Repeatability Reproducibility Ignition temperature Reactivity to air at in %/min relative relative Table 3 Slow method() Parameter Repeatability Reproducibility Ignition temperature Reactivity to air at in %/min relative relative T I 0,01 %=min 10 C/min 0,5 C/min

49、 10 C/min 0,5 C/min 10 C/min 3 C6 C 600 C 10 % 20 % 0,5 C/min 3 C6 C 525 C 20 % 40 %ISO 12982-1:2000(E) 8 ISO 2000 All rights reserved Key 1 Reproducibility, 2 Repeatability, Figure 4 Precision as function of the reactivity to air at Key 1 Reproducibility, 2 Repeatability, Figure 5 Precision as function of the reactivity to air