1、 Reference number ISO 23202:2006(E) ISO 2006INTERNATIONAL STANDARD ISO 23202 First edition 2006-06-01 Aluminium oxide used for the production of aluminium Determination of particles passing a 20 micrometre aperture sieve Oxyde daluminium utilis pour la production de laluminium Dtermination de la fin
2、esse des particules: mesure du passant 20 micromtres ISO 23202:2006(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 which are embedded are licensed to and insta
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5、lease inform the Central Secretariat at the address given below. ISO 2006 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 photocopying and microfilm, without permission in writ
6、ing 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 Switzerland ii ISO 2006 All rights reservedISO 23202:
7、2006(E) ISO 2006 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references . 1 3 Principle. 1 4 Safety . 1 5 Reagents 1 6 Apparatus 2 7 Sampling and sample preparation 3 8 Procedure 3 9 Calculation and expression of results 5 10 Precision 5 11 Quality contro
8、l. 5 12 Test report . 6 Annex A (informative) Results of test programme . 7 Annex B (normative) Determination of effective aperture of the test sieve. 8 Bibliography . 10 ISO 23202:2006(E) iv ISO 2006 All rights reservedForeword ISO (the International Organization for Standardization) is a worldwide
9、 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 a subject for which a technical committee has been established has the right to be represented on that
10、committee. International organizations, 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 acc
11、ordance 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 committees are circulated to the member bodies for voting. Publication as an International Standard requ
12、ires 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 not be held responsible for identifying any or all such patent rights. ISO 23202 was prepared by Technic
13、al Committee ISO/TC 226, Materials for the production of primary aluminium. ISO 23202:2006(E) ISO 2006 All rights reserved v Introduction This International Standard is based on Australian method, AS 2879.2-2003, Alumina Determination of particles passing a 20 micrometre aperture sieve. The Minus 20
14、 Micron reference material ASCRM 026 was released in December 2003 by SAI Global, along with a Technical Report on its preparation (TR 2.26-2003, Certified reference materials Alumina Preparation and certification of ASCRM 026). These are available from SAI through their website: http:/.au/ INTERNAT
15、IONAL STANDARD ISO 23202:2006(E) ISO 2006 All rights reserved 1 Aluminium oxide used for the production of aluminium Determination of particles passing a 20 micrometre aperture sieve 1 Scope This International Standard sets out a wet-sieving procedure for the determination of the percentage by mass
16、of particles of smelter-grade alumina passing a 20 m aperture sieve. This procedure is applicable for aluminas with a 20 m content up to 4 %. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited
17、 applies. For undated references, the latest edition of the referenced document (including any amendments) applies. ISO 802:1976, Aluminium oxide primarily used for the production of aluminium Preparation and storage of test samples ISO 806:2004, Aluminium oxide primarily used for the production of
18、aluminium Determination of loss of mass at 300 C and 1 000 C ISO 3310-3, Test sieves Technical requirements and testing Part 3: Test sieves of electroformed sheets 3 Principle A test sample of alumina is sieved on a 20 m electroformed sieve, using acetone, and the retained material is determined gra
19、vimetrically after drying at 300 C. 4 Safety Chemicals used may be hazardous or toxic and reference should be made to the appropriate Material Safety Data Sheets. CAUTION ACETONE PRESENTS A FLAMMABILITY RISK AND SHOULD BE USED IN A SUITABLE EXTRACTION HOOD. 5 Reagents 5.1 Acetone, analytical reagent
20、 grade. 5.2 Desiccant. Phosphorous pentoxide, activated alumina and molecular sieves have been found to be suitable. Silica gel is not a suitable desiccant. ISO 23202:2006(E) 2 ISO 2006 All rights reservedWARNING PHOSPHOROUS PENTOXIDE IS A HAZARDOUS MATERIAL AND REFERENCE SHOULD BE MADE TO THE APPRO
21、PRIATE MATERIAL SAFETY DATA SHEET. 5.3 Ethanol or methanol, technical grade. 6 Apparatus Ordinary laboratory equipment and the following. 6.1 Test sieve, consisting of a frame, nominally of diameter 75 mm to 150 mm, with an electroformed 20 m aperture mesh constructed and tested in accordance with I
22、SO 3310-3. The aperture shape shall be round and the sieving medium shall be supported by a suitable grid to provide adequate strength. The construction materials shall be such that the sieve is resistant to chemical corrosion and no physical damage shall occur as a result of heating to 110 C. The m
23、esh shall be attached to the frame of the sieve such that particles cannot lodge in any part of the joining seam. NOTE Two suitable mesh sizes are commonly available, 317 # and 570 #. The open area of the mesh is approximately 17 % for the 570 #, and 3,5 % for the 317 #. Thus, the 570 # sieve is mor
24、e efficient but more fragile than the 317 # sieve. 6.2 Sieve brush, which is acetone-compatible, of high quality with an unpainted handle and soft bristles. Any paint on the brush shall be removed. NOTE 1 Westart Akrilik Filbert #6 or #8 brushes have been found suitable. This information is given fo
25、r the convenience of users of this International Standard and does not constitute an endorsement by ISO of the product named. Equivalent products may be used if they can be shown to lead to the same results. NOTE 2 A stiff-bristled brush (e.g. hogs bristle) is not suitable, as it may bias the analys
26、is high and may also damage the sieve mesh. NOTE 3 A dark-bristled brush is useful, as any alumina particles adhering to the bristles are easily seen. 6.3 Ovens, fitted with mechanical air circulation and capable of being controlled at (300 10) C. 6.4 Vacuum desiccator, containing an aluminium heat
27、sink, in accordance with ISO 806, and a tray containing desiccant. A tray containing approximately 250 g of desiccant is suitable. 6.5 Platinum crucibles, of 25 ml capacity and approximate dimensions of 35 mm diameter and 40 mm depth and fitted with lids. Two crucible and lid sets are required for e
28、ach determination. The crucible and lid sets shall be conditioned by placing in an oven maintained at (300 10) C for 30 min, then cooled and stored in the heat sink in the desiccator. 6.6 Wash bottle, made of polyethylene and filled with reagent-grade acetone. 6.7 Ultrasonic bath. 6.8 Sample scoop,
29、made of stainless steel or brass with a handle. Nominally this scoop shall take up to 0,5 g of alumina when loaded. (See Figure 1.) Dimensions in millimetres ISO 23202:2006(E) ISO 2006 All rights reserved 3aWall thickness (nominal). Figure 1 Typical sampling scoop 7 Sampling and sample preparation A
30、 50 g test sample shall be prepared from the laboratory sample as specified in ISO 802, taking particular care to avoid loss of fine particles through dusting. The test sample shall be mixed well by manual or mechanical tumbling in a sealed container that is not more than 75 % full. After tumbling,
31、let the container rest to allow fines to settle. Each test portion shall be extracted with the sample scoop (6.8), taking a number of grabs to make up the required mass. Manual tumbling shall be repeated between extraction of test portions. A flat-bladed spatula or vibrating spatula should not be us
32、ed, as segregation may occur. 8 Procedure 8.1 Check the sieve The sieve shall be checked to ensure that the mesh is not ruptured and that there is not excessive aperture blinding. When holding the sieve up to a light source, areas of blinding are visible as being darker in appearance. If more than 3
33、0 % of the sieve mesh is blinded, the sieve shall be cleaned as specified in 8.2. 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 f
34、or ruptures. NOTE Ruptures can be successfully repaired using silver solder. When a repair is carried out, check the repaired area under magnification to ensure that the rupture is covered and that the solder is bonded to the mesh. 8.2 Cleaning sieve The procedure shall be as follows. a) Submerge th
35、e sieve in a beaker containing 50 % ethanol or methanol in water. The beaker should be of sufficient diameter to hold the sieve on its side. b) Place the beaker in an ultrasonic bath and sonicate for 10 min. c) Remove the sieve and inspect for aperture blinding. d) Repeat sonication if blinding is s
36、till greater than 30 %. NOTE The sieve is placed on its side during sonication to prevent damage. ISO 23202:2006(E) 4 ISO 2006 All rights reserved8.3 Test procedure The procedure shall be as follows: a) Using the sample scoop (6.8), transfer a (2 0,1) g test portion of the test sample into a tared w
37、eighing vessel. Record the mass to the nearest 0,000 1 g (m 1 ) and transfer to a clean 20 m test sieve (6.1). b) Weigh two conditioned platinum crucible and lid sets (A and B), and record their masses (m 2and m 3 , respectively). Using the sample scoop, transfer another (2 0,1) g test portion to cr
38、ucible A. Reweigh crucible set A and record the mass (m 4 ). Record all masses to the nearest 0,000 1 g. Crucible set A holds the test portion used for moisture correction and is retained in a desiccator until Step i). Crucible set B is used to dry the sieved test portion. Both test portions should
39、be weighed out at the same time. NOTE 1 The crucible and lid set conditioning procedure is given in 6.5. c) Place the sieve with the test portion in a fume cupboard. d) Wet the test portion in the sieve with approximately 50 ml of acetone poured from the wash bottle (6.6), and then sieve the materia
40、l by flooding with a jet of acetone delivered from the wash bottle whilst brushing (see 6.2). Wash any alumina that collects on the inside frame wall of the sieve onto the sieve mesh with acetone. Collect the spent acetone and dispose of or recycle in accordance with environmental good practice. Pre
41、ssure on the brush should be just sufficient to cause slight bending of the bristles. The purpose of brushing is to suspend the fines in the acetone, to enable them to be washed through the sieve. NOTE 2 Take care not to lose any sample as the jet of acetone impinges on the sieve. Splashing may resu
42、lt in a loss of sample. e) Continue sieving for 10 min in a manner such that all of the alumina and all parts of the sieve mesh receive equal washing and brushing. f) Remove any alumina from the brush by pressing the brush firmly against the inside wall of the sieve, simultaneously washing with a je
43、t of acetone and rotating the brush. The total volume of acetone passing through the sieve in a single determination should be at least 400 ml. If it is less, not all the fines may be washed through the sieve. A low volume of acetone indicates that the sieve is blinded due to inadequate cleaning and
44、 inspection (see 8.2) or the sieve may be overloaded with fines. In the case of the latter, clean the sieve (see 8.2) and repeat the analysis using nominally a 1 g sample. g) Quantitatively transfer the contents of the sieve to crucible B and wash any adhering alumina from the sieve into the crucibl
45、e with a jet of acetone. NOTE 3 This step is conveniently accomplished using a funnel held on a retort stand over the receiving crucible. h) Carefully evaporate to dryness in a fume hood, avoiding sample loss. NOTE 4 An infrared lamp is suitable for evaporating acetone. i) Heat crucible sets A and B
46、 in the oven (6.3) maintained at (300 10) C for 2 h. WARNING DO NOT TRANSFER THE CRUCIBLES TO THE OVEN UNTIL THE ACETONE HAS EVAPORATED COMPLETELY. j) Remove the crucible sets from the oven, place in the heat sink in the desiccator (ensuring the lids cover the crucible) and immediately evacuate the
47、desiccator. Allow to cool. ISO 23202:2006(E) ISO 2006 All rights reserved 5 k) Reweigh crucible sets A and B and record the masses (m 5and m 6 , respectively), to the nearest 0,000 1 g. 9 Calculation and expression of results The mass fraction, in percent of material passing the 20 m aperture sieve
48、(w 20 ), shall be calculated from the following equation and expressed to one decimal place on an as-received basis: () ( ) () 6342 20 152 100 100 mmmm w mmm = where w 20 is the mass fraction, in percent of the material passing the 20 m aperture sieve; m 6 is the mass of crucible set B and the +20 m
49、 fraction of the test portion after heating at 300 C, in grams; m 3 is the mass of empty crucible set B, in grams; m 4 is the mass of crucible set A and sample prior to heating at 300 C, in grams; m 2 is the mass of empty crucible set A, in grams; m 1 is the mass of sample taken for the sieve test, in grams; m 5 is the mass of crucible set A and sample after heating at 300 C, in grams. 10 Precision A test programme of the method in this Internatio
