BS 6043-2 20 1-2001 Methods of sampling and test for carbonaceous materials used in aluminium manufacture - Electrode coke - Carboxy reactivity of calcined coke - Determination of .pdf

1、| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BRITISH STANDARD BS 6043-2.20.1:2001 ISO 1

2、2981-1:2000 ICS 71.100.10; 75.160.10 NO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAW Methods of sampling and test for carbonaceous materials used in aluminium manufacture Part 2: Electrode coke Section 2.20: Carboxy reactivity of calcined coke Subsection 2.20.1: Determination

3、of the reactivity 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 36969 2 BS 6043-2.

4、20.1:2001 Amendments issued since publication Amd. No. Date Comments National foreword This British Standard reproduces verbatim ISO 12981-1:2000 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

5、aluminium industry, 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 developm

6、ents and promulgate 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

7、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 their correct applicat

8、ion. Compliance with 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 v, a blank page, pages 1 to 7 and a back cover. The BSI copyright notice displayed in this

9、 document indicates when the document was last issued.Reference number ISO 12981-1:2000(E) INTERNATIONAL STANDARD ISO 12981-1 First edition 2000-11-01 Carbonaceous materials used in the production of aluminium Calcined coke Determination of the reactivity to carbon dioxide Part 1: Loss in mass metho

10、d Produits carbons utiliss pour la production de laluminium Coke calcin Dtermination de la ractivit au dioxyde de carbone Partie 1: Mthode par perte de masse BS60432.20.1:2001ii BS60432.20.1:2001ISO -189211:(0002E)iii Contents Page Foreword.iv Introduction.v 1 Scope 1 2 Normative references 1 3 Prin

11、ciple1 4 Reagent.1 5 Apparatus .2 6 Sampling.5 7 Preparation of test sample6 8 Procedure .6 9 Expression of results 7 10 Precision.7 11 Test report 7 BS60432.20.1:2001ISO -189211:(0002E) iv Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standa

12、rds bodies (ISO member 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 organ

13、izations, governmental 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 i

14、n 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. Attention is drawn to the possibility t

15、hat some of the elements of this part of ISO 12981 may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. International Standard ISO 12981-1 was prepared by Technical Committee ISO/TC 47, Chemistry, Subcommittee SC 7, Aluminium oxide, cr

16、yolite, aluminium fluoride, sodium fluoride, carbonaceous products for the aluminium industry. ISO 12981 consists of the following parts, under the general title Carbonaceous materials used in the production of aluminium Calcined coke Determination of the reactivity to carbon dioxide: Part 1: Loss i

17、n mass method Part 2: Thermogravimetric method BS60432.20.1:2001ISO -189211:(0002E)v Introduction The reactivity of a calcined coke to carbon dioxide is assessed by determining the loss in mass of a sample exposed in accordance with the following chemical reaction: C CO 2 2C O This determination all

18、ows an assessment of the later anode reactivity to carbon dioxide in the electrolysis cell. BS60432.20.1:2001BS60432.20.1:2001INTENRATIONAL TSANDADR ISO 18921-:10002(E)1 Carbonaceous materials used in the production of aluminium Calcined coke Determination of the reactivity to carbon dioxide Part 1:

19、 Loss in mass method 1 Scope This part of ISO 12981 specifies a method for the determination, by a loss in mass method, of the reactivity of calcined petroleum coke, used in the manufacture of anodes for the production of aluminium, to carbon dioxide. 2 Normative references The following normative d

20、ocuments contain provisions which, through reference in this text, constitute provisions of this part of ISO 12981. 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 12981 are encouraged t

21、o 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 currently valid International Standards. ISO 383, Labo

22、ratory glassware Interchangeable conical ground joints. ISO 5725-2, Accuracy (trueness and precision) of measurement methods and results Part 2: Basic method for the determination of repeatability and reproducibility of a standard measurement method. ISO 6375, Carbonaceous materials for the producti

23、on 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 Determination of particle size d

24、istribution. 3P r i n c i p l e A coke sample of 5 g having a grain size of 1 mm to 1,4 mm is exposed to a carbon dioxide (CO 2 ) stream of 50 l/h for approximately 100 min at 1 000 C. The loss in mass is then measured. 4 Reagents 4.1 CO 2 , having a minimum purity of 99,9 % by volume and maximum im

25、purity levels of O 2 : 100 mol/mol, H 2 O: 130 mol/mol, N 2 + Ar: 800 mol/mol. BS60432.20.1:2001ISO -189211:(0002E) 2 4.2 Calibration standard, certified with a precisely known value of reactivity to carbon dioxide of about 10 % by mass. NOTE Suitable materials are commercially available. 5 Apparatu

26、s A diagram of a complete apparatus is shown in Figure 1. 5.1 Ordinary laboratory apparatus. 5.2 Furnace, with a vertical, single-zone tube ensuring good vertical temperature distribution and capable of heating from 20 Ct o10 00C in less than 1 h and maintaining the temperature at (1 000 3) C. The c

27、haracteristics and dimensions of a typical furnace are shown in Figure 2. 5.3 Tube reactor, consisting of two quartz tubes and a cap, with ground-glass joints (ISO 383, NS 29/32). The characteristics and dimensions of a typical tube reactor assembly are shown in Figure 3 with the following component

28、s: 5.3.1 External tube, containing a) a gas inlet, positioned at the top of the external tube, allowing the gas to flow down to the bottom of the tube and to be preheated before flowing up through the coke bed; b) a protection tube for the thermocouple positioned so that the tip of the thermocouple

29、lies 5 mm underneath the fritted disc. The bottom of the thermocouple protection tube and the gas inlet shall be external to the furnace. 5.3.2 Inner reaction tube, fitted inside the external tube. 5.3.3 Fritted disc, having a 250 mm to 500 mm pore size, fitted inside the inner reaction tube and pos

30、itioned so that the base of the coke bed lies in the middle of the furnace. 5.3.4 Cap, containing a gas outlet, clamped to the top of the inner reaction tube. 5.4 Thermocouple, chromel alumel, K-type, having an accuracy of better than 0,375 %, a diameter of 2 mm and a minimum length of 200 mm. 5.5 T

31、emperature control unit, consisting of a two-point temperature PID controller with a set-value adjuster (adjustment error 0,5 %) and with a digital temperature display. The set-point value shall be selected so that the tube reactor thermocouple indicates 1 000 C. 5.6 Flow meter, with a calibrated sc

32、ale, for the CO 2 (p = 0,1 MPa), having a full-scale reading of 60 l/h and an accuracy of better than 2%. 5.7 Pressure control, comprising a valve to regulate the pressure, and a manometer having a scale reading from of 0 MPa to 1,0 MPa. BS60432.20.1:2001ISO -189211:(0002E)3 Figure 1 CO 2 reactivity

33、 apparatus BS60432.20.1:2001ISO -189211:(0002E) 4 Dimensions in millimetres Figure 2 Characteristics and dimensions of a typical furnace BS60432.20.1:2001ISO -189211:(0002E)5 Dimensions in millimetres Key 1C O 2 in 2C O 2 out 3 Test sample (5 g) Figure 3 Tube reactor with test sample 6 Sampling Take

34、 a sample of the coke in accordance with the procedure specified in ISO 6375. BS60432.20.1:2001ISO -189211:(0002E) 6 7 Preparation of test sample Divide the sample (see clause 6) into three fractions by sieving in accordance with ISO 12984. The fractions shall have the following dimensions: I 1,4 mm

35、; IIa 1 mm to 1,4 mm; III 1 mm. Crush fraction I to produce fraction llb so that most of fraction llb has the following dimensions after sieving: l l b 1mmto1 ,4mm. Thoroughly mix fractions IIa and llb. Many granular materials are coated with oil. In such cases, remove the oil from the mixture of fr

36、actions IIa and IIb with dichloromethane, using the procedure specified in ISO 8723. Dry the mixture of fractions IIa and llb at (110 5) C to constant mass, i.e. until consecutive weighings at 5 min intervals differ by less than 0,1 %. Take a test sample of (5 0,01) g from the mixture of fractions I

37、Ia and IIb and weigh it to the nearest 0,001 g. 8 Procedure 8.1 Calibration Calibrate the apparatus once a week and after any maintenance of the apparatus, for instance replacement of the reaction tube or thermocouple. Set the reaction time to 100 min. Carry out two measurements using the calibratio

38、n standard (4.2) and calculate the average result (see clause 9). Calibrate the apparatus by calculating the reaction time, t r , in accordance with the following equation: t w w r RC,cal RC,meas 100 = where w RC,cal is the certified value of the reactivity of the calibration standard, expressed as

39、a mass fraction in percent; w RC,meas is the measured value of the reactivity of the calibration standard to carbon dioxide, expressed as a mass fraction in percent. 8.2 Determination Switch on the furnace and set the temperature control unit (5.5) to 1 000 C. Insert the empty inner reaction quartz

40、tube (5.3.2) and fix the cover with the clamp. Open the CO 2 gas valve and regulate the pressure to 0,2 MPa and the flow rate to 50 l/h. When the furnace temperature has stabilized to (1 000 3) C, insert the weighed test sample into the reaction tube. After the reaction time has passed, switch off t

41、he furnace. After a further 30 min, stop the CO 2 gas, remove the reaction tube, and place it in a holder to cool. When the reaction tube has cooled, weigh the remaining test sample to the nearest 0,001 g. BS60432.20.1:2001ISO -189211:(0002E)7 9 Expression of results Calculate the value of the react

42、ivity to carbon dioxide w RC , expressed as a mass fraction in percent, in accordance with the following formula: w RC = mm m 01 0 100 where m 0 is the initial mass, expressed in grams, of the test sample before reaction with carbon dioxide; m 1 is the final mass, expressed in grams, of the test sam

43、ple after reaction with carbon dioxide. 10 Precision 10.1 Interlaboratory study A series of tests were carried out in accordance with ISO 5725-2 to determine the precision data. In 1993 samples were tested in over 20 laboratories, giving the following results. 10.2 Repeatability The difference betwe

44、en the values of duplicate determinations, carried out in rapid succession by the same operator using the same apparatus on the same laboratory sample, is not expected to exceed the following repeatability limit r = 7 % (relative) 10.3 Reproducibility The difference between the values of the average

45、 of duplicate determinations obtained with two laboratories using this method for the analysis of the same laboratory sample is not expected to exceed the following reproducibility limit R = 15 % (relative) 11 Test report The test report shall include the following information: a) an identification

46、of the sample; b) the method used with reference to this part of ISO 12981; c) the date of the test and the results, expressed in accordance with clause 9; d) any unusual features noted during the determination; e) any operation not included in this part of ISO 12981 or in the International Standard

47、s to which reference is made, or regarded as optional; f) the name and address of the certifying organization for the calibration standard. BS60432.20.1:2001BS 6043-2.20.1:2001 ISO 12981-1:2000 BSI 389 Chiswick High Road London W4 4AL | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |

48、 | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | BSI British Standards Institution BSI is the independent national body responsible for preparing British Standa

49、rds. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standards are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using this British