《BS-ISO-15906-2007.pdf》由会员分享，可在线阅读，更多相关《BS-ISO-15906-2007.pdf（14页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS ISO 15906:2007 Carbonaceous materials for the production of aluminium Baked anodes Determination of the air permeability ICS 71.100.10 ? Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS IS
2、O 15906:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 June 2007 BSI 2007 ISBN 978 0 580 52939 9 National foreword This British Standard was published by BSI. It is the UK implementation of ISO 15906:2007. The UK participation in its
3、 preparation was entrusted to Technical Committee CII/24, Raw materials for the aluminium industry. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are re
4、sponsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontroll
5、ed Copy, (c) BSI Reference number ISO 15906:2007(E) INTERNATIONAL STANDARD ISO 15906 First edition 2007-05-01 Carbonaceous materials for the production of aluminium Baked anodes Determination of the air permeability Produits carbons utiliss pour la production de laluminium Anodes cuites Dtermination
6、 de la permabilit lair BS ISO 15906:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ii Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontr
7、olled Copy, (c) BSI 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 normally carried out through ISO technical committees. Each member body interested in
8、 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 in the work. ISO collaborates closely with the International Electrotechnical Commiss
9、ion (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. Draft International Standards adopted by the technical
10、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 document may be the subject of patent rights. ISO shall
11、not be held responsible for identifying any or all such patent rights. ISO 15906 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary aluminium. BS ISO 15906:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:
12、00 2007, Uncontrolled Copy, (c) BSI iv Introduction Anode performance in aluminium reduction cells can be partially characterized by the measurement of the gas permeability. Higher permeability allows attack and consumption of the anode by air and C02, thus shortening the life and overall performanc
13、e of the anode. BS ISO 15906:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 1 Carbonaceous materials for the production of aluminium Baked anodes Determination of the air permeability 1 Scope This Interna
14、tional Standard describes a method for the measurement of the air permeability of baked anodes, by determining the resistance to airflow of a specimen of specified volume at room temperature, within the range of air permeability between 0,01 nPm (nanoperms) and 10 nPm. “Green” anodes are considered
15、to be impermeable to gas. Therefore, this test is most applicable to “baked” carbon material. NOTE This method can also be used for measuring other carbon materials (e.g. microporous carbon materials), but precision statements are not available for other carbon materials. 2 Normative references The
16、following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 8007-2:1999, Carbonaceous materials used in the p
17、roduction of aluminium Sampling plans and sampling from individual units Part 2: Prebaked anodes 3 Terms and definitions For the purposes of this document, the following terms and definitions apply. 3.1 sample portion of carbon from a baked anode 3.2 test specimen article prepared from a sample 4 Pr
18、inciple The air permeability of a sample is determined by a comparative method. The time necessary to draw a specified volume of air through the test specimen is measured. This time is compared to the time necessary to draw a specified volume of air through a standard with known air permeability. Th
19、is comparison yields the air permeability of the sample material. 5 Apparatus 5.1 Callipers, with 0,01 mm reading precision. BS ISO 15906:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 2 5.2 Air permeabil
20、ity unit equipped as in 5.2.1 to 5.2.3. 5.2.1 Membrane vacuum pump, with an inlet to generate vacuum down to 100 mbar, and an outlet to generate high pressure up to 4 bar. The maximum flow rate has to reach 25 l/min. 5.2.2 Permeability cell, as shown in Figure 1. The cell is designed to ensure an ai
21、rtight sealing around the periphery of the sample. A rubber tube is forced as a seal against the cylindrical test specimen by means of compressed air. The porous filter-paper and the sponge-rubber protect the vacuum pump from particles and/or dust from the sample. 5.2.3 U-tube manometer, with light
22、fork sensors as shown in Figure 2. The U-tube is directly linked with the vacuum pump and is placed parallel to the permeability cell. It has a working length of 220 mm, an internal diameter of 16 mm 1 mm and an external diameter of 20 mm. It is filled to the equilibrium mark with a non-volatile, no
23、n-hygroscopic liquid of low viscosity and density, such as dibutylphtalate or a light-grade mineral oil. Thereby, the vacuum and the air volume flowing through the test specimen can easily be measured by following the oil level inside the U-tube. There are three light fork sensors. The lowest one (s
24、ensor 3) is located at 145 mm below the mark line of equilibrium. The two other sensors are located at 30 mm (sensor 1) and at 80 mm (sensor 2) below the equilibrium mark. The connection to the vacuum pump can be closed by a valve, which then leads to a decrease of the vacuum by air flowing through
25、the test specimen due to its air permeability. BS ISO 15906:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 3 Dimensions in millimetres Key 1 test specimen 2 rubber tube 3 porous filter-paper 4 rubber spon
26、ge 5 movable clamping device 6 stationary piston 7 plastic hose 8 compressed air intake 9 vacuum system Figure 1 Permeability cell BS ISO 15906:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 4 Dimensions
27、in millimetres Key 1 proximity sensor 1 2 proximity sensor 2 3 proximity sensor 3 4 mark line of equilibrium 5 air inlet 6 vacuum system Figure 2 U-tube manometer BS ISO 15906:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontro
28、lled Copy, (c) BSI 5 5.3 Standards with known air permeability, high-precision capillaries with known air permeability suitable for calibrating the air permeability unit.1) A range of permeability values for this standard of between 1 and 2 nPm is appropriate. The capillaries are mounted in a holder
29、 which fits onto the cell clamping device (50 mm diameter) of the air permeability unit, see Figure 3. A proper seal guarantees that there is no air leakage between the capillary and the metallic holder. Dimensions in millimetres Key 1 capillary 2 holder 3 screw cap 4 seal Figure 3 Standard with kno
30、wn air permeability 5.4 Impermeable disc, having the same dimensions as the test specimen. 1) Standards with known air permeability can be certified from the Netherlands Measurements Institute, NMI, in Dordrecht, The Netherlands. BS ISO 15906:2007 Licensed Copy: London South Bank University, London
31、South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 6 6 Sampling and preparation of test specimens 6.1 Prepare samples taken as defined in ISO 8007-2:1999 in the shape of a cylinder. 6.2 Select, at random, one representative core. Cut at least 20 mm from the outermo
32、st end of the core. Discard this portion. 6.3 Carefully cut a 20 mm portion from the adjacent area of the core. Blow any dust or particulate off the 20 mm section and dry it in an oven at 110 C for 4 h. 6.4 Measure the height at four points, 90 apart, on the periphery of the circular end faces, to t
33、he nearest 0,01 mm, using the callipers (5.1). Make two sets of diameter measurements, to the nearest 0,01 mm, using the callipers (5.1). Each set shall consist of four measurements, one at each end and two at intermediate points along an axial line. These sets shall lie at 90 to each other. Determi
34、ne the mean length and the mean of each of the two sets of diameter measurements. 6.5 The diameter of the test specimen shall be 50 mm 0,4 mm, and the height of the test specimen shall be 20 mm with the two faces parallel within 0,05 mm. 7 Calibration and standardization Calibrate the apparatus by m
35、easuring the air permeability of a suitable standard (5.3) according to the procedure given in Clause 8. 8 Procedure 8.1 Check all connections, make sure they are airtight and verify that there are no leaks by performing a leak check using the impermeable disc (5.4). 8.2 Place either the calibration
36、 standard (5.3) or test specimen (Clause 6), in the test apparatus and expand the rubber tube to ensure an airtight seal. 8.3 Evacuate the system until the liquid in the U-tube reaches the sensor 3. Then close the connection to the vacuum tube, using the valve, so causing a decrease of the vacuum by
37、 air flowing through the standard or test specimen due to its air permeability. When the liquid level reaches sensor 2, record the time. When the liquid level reaches sensor 1, record the time again and calculate the time difference between sensors 2 and 1. 9 Calculation of results 9.1 Determination
38、 of the calibration factor fc by using the standard of known air permeability (5.3) Calculate the calibration factor fc according to Equation (1). ccc 1963 20 ftD= (1) where fc is the calibration factor; tc is the time difference, in s; Dc is the air permeability of the standard, in nPm; BS ISO 1590
39、6:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 7 1963 corresponds to the cross-sectional surface area of a 50 mm diameter test specimen, to be tested later; 20 corresponds to the nominal height of the t
40、est specimen. 9.2 Determination of the air permeability Ds of the test specimen Calculate the air permeability Ds of the sample according to Equation (2). cs s ss fh D tA = (2) where Ds is the air permeability of the sample, expressed in nPm; ts is the time difference, in s; hs is the height of the
41、test specimen, in mm; As is the cross-sectional surface area of the test specimen, in mm2. 10 Precision and bias 10.1 General Precision statements are valid for anode samples in the range 0,7 nPm to 3,4 nPm. 10.2 Repeatability According to document ISO/TC 47/SC 7 N 1369: r = 0,06 (nPm) 10.3 Reproduc
42、ibility According to document ISO/TC 47/SC 7 N 1369: R = 0,04X(nPm) + 0,09 (nPm) where X is the material average. 11 Test report The test report shall include the following information: a) a reference to this International Standard; b) the names of the producer and customer; c) the number and refere
43、nce marking of the batches; d) the date and place of test; e) the test results. BS ISO 15906:2007 Licensed Copy: London South Bank University, London South Bank University, Sun Jun 17 07:16:13 GMT+00:00 2007, Uncontrolled Copy, (c) BSI BS ISO 15906:2007 BSI 389 Chiswick High Road London W4 4AL BSI B
44、ritish Standards Institution BSI is the independent national body responsible for preparing British Standards. 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 o
45、f 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 Standard would inform the Secretary
46、of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: +44 (0)20 8996 9000. Fax: +44 (0)20 8996 7400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically receive the latest editions of standard
47、s. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel: +44 (0)20 8996 9001. Fax: +44 (0)20 8996 7001. Email: ordersbsi-. Standards are also available from the BSI website at http:/www.bsi-. In response to orders for int
48、ernational standards, it is BSI policy to supply the BSI implementation of those that have been published as British Standards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its
49、Technical Help to Exporters Service. Various BSI electronic information services are also available which give details on all its products and services. Contact the Information Centre. Tel: +44 (0)20 8996 7111. Fax: +44 (0)20 8996 7048. Email: infobsi-. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of standards. For details of these and other benefits c