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1、 Reference number ISO 2926:2005(E) ISO 2005 INTERNATIONAL STANDARD ISO 2926 Second edition 2005-03-15 Aluminium oxide used for the production of primary aluminium Particle size analysis for the range 45 m to 150 m Method using electroformed sieves Oxyde daluminium utilis pour la production daluminiu
2、m primaire Analyse granulomtrique dans la gamme 45 m 150 m Mthode par emploi de tamis lectroforms ISO 2926:2005(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 edited unless the typefaces
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5、nt that a problem relating to it is found, please inform the Central Secretariat at the address given below. ISO 2005 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopyi
6、ng 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 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerla
7、nd ii ISO 2005 All rights reserved ISO 2926:2005(E) ISO 2005 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 normally carried out thr
8、ough 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 in the work. ISO collabo
9、rates 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 2. The main task of technical committees is to prepare International Stand
10、ards. 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 that some of the elements of
11、this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 2926 was prepared by Technical Committee ISO/TC 226, Materials for the production of primary aluminium. This second edition cancels and replaces the first edition (
12、ISO 2926:1974), which has been technically revised to reflect modern industry practice, and has substantially improved accuracy and precision over the first edition. The major changes are: the mandatory use of electroformed sieves instead of woven wire sieves; the mandatory use of a sieve shaker wit
13、h a vertical hammer-drop action concurrent with the lateral sieving action; a different set of nominal aperture sizes to correspond to modern industry practice; weighing of fractions “on-sieve“ rather than “off-sieve“; changed sample preparation (no pre-drying); removal of the limit of 50 % atmosphe
14、ric relative humidity; calculation of percentages using a “mass recovered“ denominator rather than “original mass“. -,-,- ISO 2926:2005(E) iv ISO 2005 All rights reserved Introduction This International Standard is based on AS 2879.6-1995 prepared by Standards Australia. -,-,- INTERNATIONAL STANDARD
15、 ISO 2926:2005(E) ISO 2005 All rights reserved 1 Aluminium oxide used for the production of primary aluminium Particle size analysis for the range 45 m to 150 m Method using electroformed sieves 1 Scope This International Standard specifies a dry sieve method using electroformed sieves for determini
16、ng the mass distribution of the particle sizes in aluminium oxide used for the production of primary aluminium. This method is applicable to calcined aluminium oxide containing a maximum of 20 % mass fraction of particles having a mean diameter exceeding 150 m, and containing a maximum of 15 % mass
17、fraction of particles having a mean diameter less than 45 m. This method is not applicable to the use of woven wire sieves. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For unda
18、ted references, the latest edition of the referenced document (including any amendments) applies. ISO 3310-3, Test sieves Technical requirements and testing Part 3: Test sieves of electroformed sheets 3 Principle A test portion of the crude sample is sieved mechanically through electroformed sieves.
19、 Each of the separate fractions is weighed on the sieve, and a cumulative mass of material retained on each sieve aperture size is calculated. 4 Apparatus 4.1 Test sieves, each including a sieving medium (screen) and a frame. The frames shall be cylindrical, having nominal diameters of 200 mm and he
20、ights between 50 mm and 75 mm. A lid and a bottom receiver shall be included. The sieves, lid and bottom receiver shall be capable of being fitted together tightly to form a series of test sieves1) . The screens shall be constructed of smooth electroformed sheet having square openings. The aperture
21、tolerances shall be in accordance with ISO 3310-3. 1) Certified electroformed sieves manufactured by Bukbee-Meers of St Paul, Minnesota, USA, are examples of suitable products available commercially. This information is given for the convenience of users of this International Standard and does not c
22、onstitute an endorsement by ISO of these products. -,-,- ISO 2926:2005(E) 2 ISO 2005 All rights reserved The sieve apertures shall have nominal sizes of 150 m, 106 m, 75 m, 53 m and 45 m. 4.2 Mechanical sieve shaker, capable of clamping the sieves mounted inside each other together with the top lid
23、and bottom receiver to form a vertical assembly. The apparatus2) shall impart to the sieve assembly a simultaneous horizontal rotary motion and a vertical tapping action resulting from the fall of a hammer. This combined action shall cause sufficient displacement of the aluminium oxide particles to
24、prevent aggregation but not cause any deformation of the sieving screen or any size reduction of the aluminium oxide particles through shock or abrasion. 4.3 Laboratory top pan balance, capable of weighing the sieves to the nearest 0,01 g. The balance may be fitted with a lightweight frame mounted o
25、n the weighing pan to enable direct weighing of test sieves and receiver. 4.4 Ultrasonic bath, of sufficient capacity to immerse one test sieve fully in a vertical plane to prevent cavitation damage to the sieve sheet. 5 Procedure 5.1 Sample preparation Split the sample into test portions by rifflin
26、g or rotary sample division until the required mass is obtained. Weigh the final split to the nearest 0,01 g. The mass (m0) of the final split should fall in the range 30 g to 50 g. 5.2 Preparation of test sieves Prepare the test sieves as follows. a) Clean each test sieve (4.1) in turn by immersing
27、 it vertically in distilled water in the ultrasonic bath (4.4). A non-corrosive wetting agent may be used. Cleaning times of between 15 s and 20 s are adequate. Longer times may cause damage to the sieve screen. b) After immersion, rinse each sieve with distilled water and dry in a laboratory oven a
28、t 100 C. Ensure that the sieves are thoroughly dry. c) Cool to room temperature and weigh each sieve (masses m1) on the top pan balance (4.3) to the nearest 0,01 g. Similarly weigh the bottom receiver. 5.3 Determination Determine the size distribution as follows. a) Assemble the test sieves (4.1) on
29、 the mechanical sieve shaker (4.2) in order of increasing aperture size from bottom to top, starting with the bottom receiver. b) Spread the test portion (5.1) on the top-most sieve. Close with the tightly fitting lid and install the positioning cover. Lower the hammer onto the cover. c) Switch on t
30、he mechanical sieve shaker and allow it to operate for 30 min. 2) RO-TAP Testing sieve shakers, (W. S. Tyler Inc., Mentor, Ohio, U.S.A.), operated in accordance with the manufacturers recommended settings, are examples of suitable products available commercially. This information is given for the co
31、nvenience of users of this International Standard and does not constitute an endorsement by ISO of these products. -,-,- ISO 2926:2005(E) ISO 2005 All rights reserved 3 d) Remove the sieve stack, and weigh each sieve and its contents to the nearest 0,01 g (masses m2). e) Similarly weigh the bottom r
32、eceiver and contents. f) Clean the sieves in preparation for the next test sample as follows. Invert each sieve over a suitable container, brush the underside lightly to remove entrapped particles and tap the sieve frame lightly to remove any adhering particles. 6 Calculation of results Calculate th
33、e results as follows: a) Calculate the masses of each retained sample from the following equation: m3 = m2 m1 (1) where m3 is the mass of retained sample, in grams; m2 is the mass of test sieve plus retained sample, in grams; m1 is the mass of test sieve, in grams. In the case of the sample collecte
34、d in the bottom receiver, m1 is the mass of the bottom receiver and m2 is the mass of the bottom receiver plus contents. b) Calculate the cumulative mass m4 for each sieve size. c) Calculate the mass recovered m5, using the following equation: 53 mm= (2) where m3 is the mass of sieve contents for ea
35、ch sieve and the bottom receiver. If the mass m5 exceeds the mass of the original test portion (m0) by more than 0,5 g, or if m5 is less than m0, then another test portion should be analysed. Due to absorption of moisture during the test, some increase in mass is normal. Any loss in mass is most lik
36、ely caused by physical loss of sample. d) Calculate, to two decimal places, the cumulative percent final mass m6 for each sieve aperture size, using the following equation: 4 6 5 100 m m m = e) Prepare a table of values of m6 corresponding to each successive nominal aperture size. Report each value
37、of m6 to one decimal place. NOTE 1 It can be useful to plot a cumulative distribution curve of the mass passing through each sieve, expressed as a percentage, against the corresponding nominal aperture size, in order of decreasing aperture size. NOTE 2 Annex A gives an example of a calculation (Tabl
38、e A.1) and reporting (Table A.2) of size analysis -,-,- ISO 2926:2005(E) 4 ISO 2005 All rights reserved 7 Test report The test report shall include the following information: a) the table of cumulative percent mass retained for each nominal aperture size (m6 values), expressed as percent mass fracti
39、on of the original sample; b) reference to this International Standard, i.e. ISO 2926:2005; c) any unusual features noted during the determination and any operation not included in this International Standard which may have affected the results. 8 Precision The values for repeatability and reproduci
40、bility should not exceed those given in Table 1. Table 1 Precision for size analysis Percentage by mass (absolute) Repeatability Reproducibility Sieve fraction r R + 150 m 1,2 1,7 + 106 m 1,2 8,2 + 75 m 0,9 2,0 + 53 m 0,5 2,9 + 45 m 0,2 0,9 The results of the test programme from which these values w
41、ere derived are presented in Annex B. ISO 2926:2005(E) ISO 2005 All rights reserved 5 Annex A (informative) Example of calculation of size analysis Table A.1 Example of calculation of size analysis Mass of sieve or pan Sieve mass + mass retained Mass retained Cumulative mass Retained cumulative Siev
42、e aperture or pan m1 m2 m3 m4 m6 m g g g g % 150 411,06 412,49 1,43 1,43 3,76 106 435,93 446,10 10,17 11,60 30,48 75 430,88 446,38 15,50 27,10 71,20 53 427,12 434,60 7,48 34,58 90,86 45 408,80 410,18 1,38 35,98 94,48 Pan 284,62 286,72 2,10 Initial mass m0 = 37,81 g. Total mass recovered m5 = 38,06 g
43、. Table A.2 Example of reporting size analysis Mass fraction retained (cumulative) Sieve fraction % +150 m 3,8 +106 m 30,5 +75 m 71,2 +53 m 90,9 +45 m 94,5 ISO 2926:2005(E) 6 ISO 2005 All rights reserved Annex B (informative) Results of interlaboratory test programme A test programme using this meth
44、od was conducted according to AS 2850 on three different refinery aluminas by participants from five Australian alumina refinery laboratories. The results are shown below. The values given for each laboratory are the mean values of two separate results. The between-laboratory means xand single stand
45、ard deviations under reproducibility conditions are also shown. Table B.1 Results of test programme on three refinery aluminas by five laboratories Percentage mass fraction Mean values for each fraction Alumina sample Laboratory identity +150 m +106 m +75 m +53 m +45 m Lab 1 7,1 45,8 80,8 91,3 93,2
46、Lab 2 8,2 41,9 81,1 91,0 93,0 Lab 3 7,8 46,6 80,1 91,6 92,9 Lab 4 7,4 41,2 80,5 90,9 93,8 Lab 5 7,4 41,7 80,3 90,9 93,0 x 7,6 43,4 80,6 91,1 93,2 S-074 0,4 2,3 0,4 0,3 0,3 Lab 1 18,1 60,9 85,4 91,6 92,9 Lab 2 18,5 57,7 85,5 91,6 92,9 Lab 3 20,2 63,3 85,6 91,9 92,8 Lab 4 17,6 56,8 85,4 91,4 93,3 Lab
47、5 18,1 57,4 84,9 91,5 92,7 x 18,5 59,2 85,4 91,6 92,9 S-075 0,9 2,5 0,2 0,2 0,2 Lab 1 3,1 33,0 72,7 91,2 94,6 Lab 2 4,7 30,0 73,1 91,4 94,7 Lab 3 4,2 36,0 73,8 92,6 94,8 Lab 4 4,1 28,7 72,0 89,8 94,9 Lab 5 3,5 29,7 72,5 90,9 94,5 x 3,9 31,5 72,8 91,2 94,7 S-076 0,6 2,7 0,6 0,9 0,1 ISO 2926:2005(E) I
48、SO 2005 All rights reserved 7 Bibliography 1 AS 2850, Chemical analysis Interlaboratory test programs For determining precision of analytical method(s) Guide to the planning and conduct 2 AS 2879.6-1975, Alumina Determination of the mass distribution of particle sizes using electroformed sieves ISO 2926:2005(E) ICS 71.100.10 Price based on 7 pages ISO 2005 All rights reserved -,-,-