1、BSI Standards PublicationBS ISO 18843:2015Aluminium oxide primarilyused for the production ofaluminium Method for thedetermination of flow timeBS ISO 18843:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 18843:2015.The UK participation in its preparation w
2、as entrusted to TechnicalCommittee CII/24, Raw materials for the aluminium industry.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its c
3、orrectapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 84997 8ICS 71.100.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strat
4、egy Committee on 30 June 2015.Amendments issued since publicationDate Text affectedBS ISO 18843:2015 ISO 2015Aluminium oxide primarily used for the production of aluminium Method for the determination of flow timeOxyde daluminium principalement utilis pour la production daluminium Mthode de dtermina
5、tion du temps dcoulementINTERNATIONAL STANDARDISO18843First edition2015-06-01Reference numberISO 18843:2015(E)BS ISO 18843:2015ISO 18843:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of th
6、is publication may be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, 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 t
7、he country of the requester.ISO copyright officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 18843:2015ISO 18843:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Principle 14 Apparatus . 1
8、5 Sample preparation . 16 Procedure. 26.1 General . 26.2 Number of determinations . 26.3 Determination . 27 Reporting of results . 28 Precision . 29 Test report . 3Annex A (informative) Results of planned trial . 5Bibliography 6 ISO 2015 All rights reserved iiiContents PageBS ISO 18843:2015ISO 18843
9、:2015(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 through ISO technical committees. Each member body interested in a subject for wh
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15、informationThe committee responsible for this document is ISO/TC 226, Materials for the production of primary aluminium.iv ISO 2015 All rights reservedBS ISO 18843:2015ISO 18843:2015(E)IntroductionThis International Standard is based on Australian Standard, AS 2879.9, AluminaDetermination of flow ti
16、me. ISO 2015 All rights reserved vBS ISO 18843:2015BS ISO 18843:2015Aluminium oxide primarily used for the production of aluminium Method for the determination of flow time1 ScopeThis International Standard sets out a method for determining the amount of time taken for a given quantity of smelter-gr
17、ade alumina to flow by gravity through a precisely constructed standard funnel.NOTE Variations in the apparatus and other test variables can create significant inter-laboratory differences in results. (See Table A.1.)2 Normative referencesThe following documents, in whole or in part, are normatively
18、 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.AS 4538.2, Guide to the sampling of alumina Part 2: Preparation of sa
19、mples3 PrincipleThe standard funnel is loaded with a specified mass of alumina. The time for the alumina to flow out of the funnel is determined.4 Apparatus4.1 GeneralThe test may be carried out using manual or automatic timing. An automatic device is shown in Figure 1.4.2 Funnel, precisely construc
20、ted of a corrosion resistant metal, e.g. brass or aluminium, as shown in Figure 2 with an abrasion resistant material, e.g. hardened stainless steel, insert with an outlet diameter of (3,95 to 4,00) mm; this diameter is critical.4.3 Stand, a suitable device for supporting the funnel.4.4 Timing devic
21、e, either a stop watch or automated device capable of an accuracy of 1 s.4.5 Top-loading balance, capable of weighing 100 g to the nearest 0,1 g.4.6 Sieve, with apertures within the range (300 to 400) m to remove abnormal oversize material.4.7 Container, suitable for containing the test sample.4.8 S
22、ealable container, suitable for containing and storing the funnel.5 Sample preparationThe analytical sample shall be conditioned by exposure to the laboratory atmosphere for a minimum of 2 h in a layer of 5 mm maximum thickness. The sample shall then be split as per AS 4538.2 into three INTERNATIONA
23、L STANDARD ISO 18843:2015(E) ISO 2015 All rights reserved 1BS ISO 18843:2015ISO 18843:2015(E)portions of approximately (105 to 120) g for testing. The sample shall then be screened through a sieve (4.6) and the oversize material discarded.6 Procedure6.1 GeneralThis procedure is for manually timed de
24、terminations.6.2 Number of determinationsThree determinations shall be carried out.6.3 DeterminationEach determination shall be carried out as follows.a) Ensure the funnel is clean with no surface oxides present and dry prior to use; otherwise flow times will not be reproducible. Frequent use has us
25、ually been found to be an adequate cleaning method.b) Set up the apparatus by placing the funnel (4.2) on the stand (4.3) in a vibration-free environment.c) Ensure that the funnel is secure on the stand and that the upper surface is precisely level.d) For apparatus not in frequent use, clean the fun
26、nel by passing several portions of alumina through it see a). Discard this material prior to testing.e) Take one of the prepared samples (see Clause 5) and accurately weigh a test portion of (100 0,1) g and place into the container (4.7). (See Clause 5.)f) Pour the test portion uniformly into the fu
27、nnel while manually obstructing the outlet.g) Start the flow by removing the outlet obstruction and immediately commence timing. Stop the timing as soon as all the sample has passed through the funnel. Never tap the funnel.h) Repeat the procedure with the other two test portions (Clause 5).i) Remove
28、 the funnel from the stand and wipe the funnel clean with a dry cloth. Replace it in the sealable container (4.8) to prevent damage to the outlet orifice and minimize atmospheric oxidation of the inner surface.7 Reporting of resultsReport the average of the three results to the nearest second.8 Prec
29、isionA test programme of the method in this International Standard was carried out in accordance with AS 2850. From the results of this programme, a within-laboratory repeatability (r) and between-laboratory reproducibility (R) at the 95 % confidence level as given in Table 1 should be achieved.NOTE
30、 Results of the test programme are given in Annex A.Table 1 Precision data for flow timeRepeatability (r) Reproducibility (R)2,7 9,72 ISO 2015 All rights reservedBS ISO 18843:2015ISO 18843:2015(E)9 Test reportThe test report shall include the following information:a) identification of the sample;b)
31、a reference to this International Standard, i.e. ISO 18843;c) average flow time for the sample;d) the date on which the test was carried out;e) any factors during the course of the test which may have had an effect on the results.Figure 1 Automatic flow funnel time apparatus ISO 2015 All rights rese
32、rved 3BS ISO 18843:2015ISO 18843:2015(E)Dimensions in millimetresKeyA datum line through the funnelB hardened insert with orifice shown in situ and as detailC vertical cross sectionD top view= Radius 90 typical= Datum line= Total run out (i.e. radius tolerance is 0,1 mm)= Diameter= Finish (0,2 Fine,
33、 1,.6 Standard)= Tolerance Max./Min.FINISH 3,2 UNDTOLERANCE 0,3 UNDFigure 2 Flow funnel4 ISO 2015 All rights reservedBS ISO 18843:2015ISO 18843:2015(E)Annex A (informative) Results of planned trialA planned trial of the method in this International Standard was carried out in accordance with AS 2850
34、. Samples of three smelter grade aluminas were analysed. Results were provided in quadruplicate by six laboratories. The within-laboratory (r) and between-laboratory (R) precision data (at 95 % confidence limits) and mean flow time values calculated from the results are given in Table A.1.Table A.1
35、Precision data obtained using test samplesSample Mean flow time sRepeatability (r)Reproducibility (R)S-109 47 1,5 7, 3S-110 68 3,3 10,7S-111 82 2,9 10,8 ISO 2015 All rights reserved 5BS ISO 18843:2015ISO 18843:2015(E)Bibliography1 AS 4538.1, Guide to the sampling of alumina Part 1: Sampling procedur
36、es2 AS 2879.9, AluminaDetermination of flow time6 ISO 2015 All rights reservedBS ISO 18843:2015BS ISO 18843:2015ISO 18843:2015(E) ISO 2015 All rights reservedICS 71.100.10Price based on 6 pagesThis page deliberately left blankBSI is the national body responsible for preparing British Standards and o
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