BS 6043-2 21 1-2001 Methods of sampling and test for carbonaceous materials used in aluminium manufacture - Electrode coke - Air reactivity of calcined coke - Determination of the .pdf

1、BRITISH STANDARD BS 6043-2.21.1: 2001 ISO 12982-1:2000 Methods of sampling and test for carbonaceous materials used in aluminium manufacture Part 2: Electrode coke Section 2.21: Air reactivity of calcined coke Subsection 2.21.1: Determination of the reactivity by determination of ignition temperatur

2、e ICS 71.100.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBS 6043-2.21.1:2001 This 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 e

3、ffect on 15 July 2001 BSI 07-2001 ISBN 0 580 37422 X National foreword This British Standard reproduces verbatim ISO 12982-1:2000 and implements it as the UK national standard. The UK participation in its preparation was entrusted to Technical Committee CII/24, Methods of test for raw materials for

4、the aluminium industry, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. From 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC 27 has been renumbered as IEC 60027-1

5、. For a period of time during the change over from one numbering system to the other, publications may contain identifiers from both systems. Cross-references The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards C

6、atalogue under the section entitled “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 the

7、ir correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. 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 intere

8、sts informed; monitor related international and European developments and promulgate them in the UK. 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 date displayed in this document indi

9、cates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsINTERNATIONAL STANDARD ISO 12982-1 First edition 2000-12-15 Reference number ISO 12982-1:2000(E) Carbonaceous materials used in the production of aluminium Calcined coke Determination of the reactivity

10、 to air Part 1: Ignition temperature method Produits carbons utiliss pour la production de 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) iiISO 12982-1:2000(E) diii Contents Page 1 Scope . 1 2 Normative references .

11、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 results . 6 10 Precision . 7 11 Test report 7 Bibliography. 9ISO 12982-1:2000(E) iv Foreword ISO (the International Organization for Standardization) is a worldw

12、ide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally 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

13、that committee. International organizations, governmental and non-governmental, in liai- son 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

14、 in accordance with the rules given in the ISO/IEC Directives, 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. At

15、tention is drawn to the possibility that some of the elements of this part of ISO 12982 may be the subject of patent 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, S

16、ubcommittee SC 7, Aluminium oxide, cryolite, aluminium fluoride, sodium fluoride, carbonaceous products for the aluminium 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 react

17、ivity to air: Part 1: Ignition temperature method A thermogravimetric method will be the subject of a future part 2 to ISO 12982.INTERNATIONAL STANDARD ISO 12982-1:2000(E) d1 Carbonaceous materials used in the production of aluminium Calcined coke Determination of the reactivity to air Part 1: Ignit

18、ion temperature method 1 Scope This part of ISO 12982 describes an ignition temperature 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, w

19、hereas is used for statistical process control of calcination kilns and for anode butt quality 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

20、 provisions which, through reference in this text, constitute provisions of this part of 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 th

21、e 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 cur- rently valid International Standards. ISO 6375, Carbonaceous mate

22、rials for the production of aluminium Coke for electrodes Sampling. ISO 8723, Carbonaceous 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 Determinat

23、ion of par- t icl es iz ed i st rib ut i on . 3 Principle The reactivity to air of calcined 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

24、 heated at or , depending on the sample history and the intended application. Ignition is 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

25、. 4R e a g e n t s 4.1 Air, bottled or compressed, containing less than free water. 5 C/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 4.2 Certified calibration standard, having an ignition temperature of about at a heating rate of . 5 Apparatus Ordinary labora

26、tory apparatus and the following. 5.1 Furnace, capable of heating 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 tub

27、es and a cap, with ground-glass joints, assembled as described 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, positione

28、d near the top of the external tube, allowing gas to flow down 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 tub

29、e and the thermocouple protection tube shall extend outside 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, conta

30、ining a gas outlet, clamped to the top of the reaction tube. 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

31、 rate and temperature display. 5.5 Chart recorder, to record 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 ac

32、curacy of better than . 5.7 Pressure control, comprising a 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

33、 = 0,1 MPa 60 l/h 2% 0 MPa 1,0 MPaISO 12982-1:2000(E) d3 Dimensions in millimetres Figure 1 Characteristics and dimensions of a typical furnaceISO 12982-1:2000(E) 4 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) d5

34、 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 after sieving: IIb to Thoro

35、ughly 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 Many granular materials are coated with oi

36、l. 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 rv a lsd i f f e rb yl es st h an . Take a test sample

37、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 calibrate the thermocouple which measures the sample tempe

38、rature. 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 standard reference temperature and the actual temperature

39、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 quartz tube and fix the cover with the clamp. Heat the furn

40、ace 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 to increase the furnace temperature, plotting the tempe

41、rature 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-temperature plot by extending the two linear sec- tions of

42、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 heating rate of was used, calculate the reactivity to air

43、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 controller programmes Application Fast method Slow method S

44、tandby 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 600 C ! 600 ! 600 =50,064 + 75 364 T I 2,798 3 10 7 T 2 I

45、 ISO 12982-1:2000(E) d7 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 . NOTE Alternatively, the above calculations may be carried out automatically by a

46、 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 samples taken from the same laboratory sample, should not differ by more than the

47、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 laboratories on representative test samples taken from the same sample after the last s

48、tage 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 function of the reactivity to air for each of the methods. 11 Test report The test rep

49、ort 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 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 rega