1、BSI Standards PublicationBS ISO 2926:2013Aluminium oxide used for the production of primary aluminiumParticle size analysis for the range 45 m to 150 m Method using electro-formed sievesBS ISO 2926:2013 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 2926:2013.
2、 It supersedes BS ISO 2926:2005 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee CII/24, Raw materials for the aluminium industry.A list of organizations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
3、 purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2013.Published by BSI Standards Limited 2013ISBN 978 0 580 66584 4 ICS 71.100.10 Compliance with a British Standard cannot confer immunity from legal o
4、bligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 September 2013.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 2926:2013 ISO 2013Aluminium oxide used for the production of primary aluminium Parti
5、cle size analysis for the range 45 m to 150 m Method using electroformed sievesOxyde daluminium utilis pour la production daluminium primaire Analyse granulomtrique dans la gamme 45 m 150 m Mthode par emploi de tamis lectroformsINTERNATIONAL STANDARDISO2926Third edition2013-09-01Reference numberISO
6、2926:2013(E)BS ISO 2926:2013ISO 2926:2013(E)ii ISO 2013 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2013All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photoc
7、opying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCase postale 56 CH-1211 Geneva 20Tel. + 41 22 749 01 11Fax + 41 22 749 09 47E-
8、mail copyrightiso.orgWeb www.iso.orgPublished in SwitzerlandBS ISO 2926:2013ISO 2926:2013(E) ISO 2013 All rights reserved iiiContents PageForeword ivIntroduction v1 Scope . 12 Normative references 13 Principle 14 Apparatus . 15 Procedure. 25.1 Sample preparation 25.2 Preparation of test sieves . 25.
9、3 Determination . 26 Calculation of results . 37 Test report . 38 Precision . 4Annex A (informative) Example of calculation of size analysis . 5Annex B (informative) Determination and use of effective aperture . 6Annex C (informative) Results of interlaboratory test programme . 7Annex D (informative
10、) Ultrasonic cleaning of sieves . 9Bibliography .10BS ISO 2926:2013ISO 2926:2013(E)ForewordISO (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 throug
11、h 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 collaborat
12、es closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop this document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval cri
13、teria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject o
14、f patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the development of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name
15、 used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical
16、 Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 226, Materials for the production of primary aluminium.This third edition cancels and replaces the second edition (ISO 2926:2005), which has been technically revi
17、sed to reflect modern industry practice. The major changes are: recommended effective aperture tolerance limits have been added; sieves are cleaned by brushing rather than using an ultrasonic bath; the mass of sample to be sieved is 50 g;iv ISO 2013 All rights reservedBS ISO 2926:2013ISO 2926:2013(E
18、)IntroductionThis International Standard is based on AS 2879.6-1995 prepared by Standards Australia. ISO 2013 All rights reserved vBS ISO 2926:2013BS ISO 2926:2013Aluminium oxide used for the production of primary aluminium Particle size analysis for the range 45 m to 150 m Method using electroforme
19、d sieves1 ScopeThis International Standard specifies a dry sieve method using electroformed sieves for determining 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、 20 % mass fraction of particles having a mean diameter exceeding 150 m, and containing a maximum of 15 % mass 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 referencesThe following documents, in whole or in part,
21、 are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3310-3, Test sieves Technical requirements and te
22、sting Part 3: Test sieves of electroformed sheets3 PrincipleA test portion of the crude sample is sieved mechanically through electroformed sieves.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 Apparatus4
23、.1 Test sieves, each including a sieving medium (screen) and a frame.The frames shall be cylindrical, having nominal diameters of 200 mm and heights 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 t
24、ightly to form a series of test sieves1).The screens shall be constructed of smooth electroformed sheet having square openings. The aperture tolerances shall be in accordance with ISO 3310-3.The sieve apertures shall have nominal sizes of 150 m, 106 m, 75 m, 53 m and 45 m. Refer to Annex B for effec
25、tive aperture determination and tolerance limits.1) Certified electroformed sieves manufactured by Precision Eforming of Cortland, New York, USA, are examples of suitable products available commercially. This information is given for the convenience of users of this International Standard and does n
26、ot constitute an endorsement by ISO of these products.INTERNATIONAL STANDARD ISO 2926:2013(E) ISO 2013 All rights reserved 1BS ISO 2926:2013ISO 2926:2013(E)4.2 Mechanical sieve shaker, capable of clamping the sieves mounted inside each other together with the top lid and bottom receiver to form a ve
27、rtical 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 prevent aggregation but not cause
28、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 on the weighing pan to enable direct
29、weighing of test sieves and receiver.4.4 Brush, fine bristled, soft, a few centimetres wide.5 Procedure5.1 Sample preparationSplit the sample into test portions by riffling 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
30、 final split should fall in the range 45 to 55 g.5.2 Preparation of test sievesPrepare the test sieves as follows.a) Clean each test sieve (4.1) in turn by inverting it over a suitable container, brushing the mesh to remove trapped particles and tapping the sieve frame lightly to remove any adhering
31、 particles.b) Inspect each sieve to ensure that the mesh is not ruptured and there is not excessive aperture binding. Upon holding the sieve up to a light source, areas of blinding are visible as being darker in appearance. If more than 10 % of the sieve mesh is blinded the sieve is not sufficiently
32、 clean to use. Larger ruptures in the sieve may be seen by visual inspection. To see smaller ruptures magnification is required. Inspection using a stereo microscope is recommended; scan the entire mesh area and the edges to check for ruptures.NOTE 1 Ruptures of the mesh can be successfully repaired
33、 using silver solder or hardening synthetic resin. When a repair is performed, check the repaired area under magnification to ensure the rupture is covered and that the solder is bonded to the mesh.NOTE 2 Other options for cleaning sieves are given in Annex D.5.3 DeterminationDetermine the size dist
34、ribution as follows.a) Weigh each sieve (masses m1) on the top pan balance (4.3) to the nearest 0,01 g. Similarly, weigh the bottom receiver.b) Assemble the test sieves (4.1) on the mechanical sieve shaker (4.2) in order of increasing aperture size from bottom to top, starting with the bottom receiv
35、er.c) 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.2) RO-TAP Testing sieve shakers, (W. S. Tyler Inc., Mentor, Ohio, U.S.A.), operated in accordance with the manufacturers recommended settin
36、gs, are examples of suitable products available commercially. This information is given for the convenience of users of this International Standard and does not constitute an endorsement by ISO of these products.2 ISO 2013 All rights reservedBS ISO 2926:2013ISO 2926:2013(E)d) Switch on the mechanica
37、l sieve shaker and allow it to operate for 30 min.e) Remove the sieve stack, and weigh each sieve and its contents to the nearest 0,01 g (masses m2).f) Similarly weigh the bottom receiver and contents.6 Calculation of resultsCalculate the results as follows:a) Calculate the masses of each retained s
38、ample from the following equation:m3= m2 m1(1)wherem3is the mass of retained sample, in grams;m2is the mass of test sieve plus retained sample, in grams;m1is the mass of test sieve, in grams.In the case of the sample collected in the bottom receiver, m1is the mass of the bottom receiver and m2is the
39、 mass of the bottom receiver plus contents.b) Calculate the cumulative mass m4for each sieve size.c) Calculate the mass recovered m5, using the following equation:mm53=(2)where m3is the mass of sieve contents for each sieve and the bottom receiver.If the mass m5exceeds the mass of the original test
40、portion (m0) by more than 0,5 g, or if m5is 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 likely caused by physical loss of sample.d) Calculate, to two decimal places, the cumulativ
41、e per cent final mass m6for each sieve aperture size, using the following equation:mmm645100= e) Prepare a table of values of m6corresponding to each successive nominal aperture size. Report each value of m6to one decimal place.NOTE 1 It can be useful to plot a cumulative distribution curve of the m
42、ass 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 (Table A.1) and reporting (Table A.2) of size analysis.7 Test reportThe test report shall include the foll
43、owing information:a) the table of cumulative per cent mass retained for each nominal aperture size (m6values), expressed as per cent mass fraction of the original sample;b) a reference to this International Standard, i.e. ISO 2926:2013; ISO 2013 All rights reserved 3BS ISO 2926:2013ISO 2926:2013(E)c
44、) any unusual features noted during the determination and any operation not included in this International Standard which may have affected the results.8 PrecisionThe test program (see Annex C) was performed on four samples by seven laboratories using pre-mixing and splitting via rotary splitters. I
45、t showed that precision was partially sample dependant and thus an overall precision limit cannot be implied. The means, repeatability (r) and reproducibility (R) determined for each sample from the test program are given in Table 1.The average precisions for the four samples are also given in Table
46、 1. These averages are indicative of the precisions that can be expected from this method but users should also note the range of precisions possible for different samples as indicated by the results for the four individual test samples.Table 1 Precision for size analysis (at 95 % confidence level)M
47、eans as percentage by mass (absolute)Sieve fractionSample +150m +106m +75m +53m +45mS128 mean 1,1 19,7 65,7 90,5 95,5r 0,4 1,5 2,2 1,1 0,7R 0,6 2,6 5,2 1,6 1,2S129 mean 3,4 22,0 57,4 82,3 90,0r 0,3 0,9 1,1 0,8 0,7R 1,1 2,3 3,0 1,9 1,1S130 mean 11,0 42,0 71,2 87,0 91,9r 0,8 1,6 1,9 1,5 1,1R 2,3 2,5 2
48、,5 2,2 1,6S131 mean 2,7 44,1 85,7 97,6 99,2r 0,4 0,7 0,8 0,6 0,4R 1,6 3,1 1,5 1,0 0,5Average r 0,5 1,2 1,5 1,0 0,7R 1,4 2,6 3,0 1,7 1,1The results of the test programme from which these values were derived are presented in Annex C.4 ISO 2013 All rights reservedBS ISO 2926:2013ISO 2926:2013(E)Annex A
49、 (informative) Example of calculation of size analysisTable A.1 Example of calculation of size analysisSieve aperture or panMass of sieve or panSieve mass + mass retainedMass retainedCumulative massRetained cumula-tivem1m2m3m4m6m g g g g %150 411,06 412,49 1,43 1,43 3,76106 435,93 446,10 10,17 11,60 30,4875 430,88 446,38 15,50 27,10 71,2053 427,12 434,60 7,48 34,58 90,8645 408,80 410,18 1,38 35,98 94,48Pan 284,62 286,72 2,10Initial mass m0= 37,81 g.Total mass recovered m5= 38,06 g.Table A.2 Example
