1、BSI Standards PublicationBS ISO 19950:2015Aluminium oxide primarilyused for the production ofaluminium Determinationof alpha alumina content Method using X-ray diffractionnet peak areasBS ISO 19950:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 19950:2015
2、.The UK participation in its preparation was 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
3、 contract. Users are responsible for its correctapplication. The British Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 88353 8ICS 71.100.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the
4、authority of theStandards Policy and Strategy Committee on 31 December 2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 19950:2015 ISO 2015Aluminium oxide primarily used for the production of aluminium Determination of alpha alumina content Method using X-ray dif
5、fraction net peak areasOxyde daluminium principalement utilis pour la production daluminium Dosage de la teneur en alumine alpha Mthode utilisant la diffraction rayons X des surfaces de pic netINTERNATIONAL STANDARDISO19950First edition2015-12-01Reference numberISO 19950:2015(E)BS ISO 19950:2015ISO
6、19950:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll 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 photocopyin
7、g, 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 officeCh. de Blandonnet 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11
8、Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 19950:2015ISO 19950:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Principle 14 Reagents 15 Apparatus . 26 Procedure. 27 Calculation and expression of results . 48 Precision . 59 Test report . 6Annex A (informative) Results
9、of interlaboratory test program . 7Bibliography 8 ISO 2015 All rights reserved iiiContents PageBS ISO 19950:2015ISO 19950:2015(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing Internat
10、ional 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 committee. International organizations, governmental and non-governmental, in liaison with I
11、SO, also take part in the work. ISO collaborates 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, Pa
12、rt 1. In particular the different approval criteria 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
13、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. 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 rec
14、eived (see www.iso.org/patents).Any trade name 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 ad
15、herence to the WTO principles in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 226, Materials for the production primary aluminium.iv ISO 2015 All rights reservedBS ISO 19950:2015ISO 19950:2015(E
16、)IntroductionThis International Standard is based on an Australian Standard AS 2879.3-2010, Alumina Determination of alpha alumina content by X-ray diffraction. ISO 2015 All rights reserved vBS ISO 19950:2015BS ISO 19950:2015Aluminium oxide primarily used for the production of aluminium Determinatio
17、n of alpha alumina content Method using X-ray diffraction net peak areas1 ScopeThis International Standard sets out an X-ray diffraction method for the determination of the alpha alumina content of smelter grade alumina. The method is applicable to smelter grade alumina containing alpha phase at lev
18、els up to 50 %. The percentage by mass of alpha alumina is determined on an “as received” basis.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited appl
19、ies. For undated references, the latest edition of the referenced document (including any amendments) applies.AS 4538.2, Guide to the sampling of alumina Preparation of samples3 PrincipleThe integrated peak areas of the (012) and (116) lattice plane reflections (nominal d spacings 0,348 nm and 0,160
20、 nm) are measured for the test sample and a 100 % alpha alumina calibration standard. The ratio between the net peak area intensities for the test sample and for the standard is determined and the alpha alumina content calculated from this ratio.4 Reagents4.1 GeneralDuring the analysis, only reagent
21、s of recognized analytical reagent grade and only distilled water, or water of equivalent purity, shall be used.4.2 100 % alpha alumina calibration standard, prepared in accordance with either 4.2.1 or 4.2.2.4.2.1 A commercially available, certified 100 % alpha alumina calibration standard suitable
22、for diffraction analysis.4.2.2 An in-house produced 100 % alumina calibration standard prepared in accordance with 6.1 and using the following reagents.4.2.2.1 Hydrochloric acid (100 g/l).4.2.2.2 Smelter grade alumina.NOTE The type of alumina used as the base for the 100 % alpha alumina calibration
23、standard can affect the peak areas measured. Grades of the base alumina other than smelter grade can yield different peak area intensities.INTERNATIONAL STANDARD ISO 19950:2015(E) ISO 2015 All rights reserved 1BS ISO 19950:2015ISO 19950:2015(E)5 Apparatus5.1 X-ray diffractometer.5.2 Hydraulic press,
24、 suitable for preparing mounts.5.3 Rotary divider or riffle.5.4 Grinding mill, capable of grinding alumina to a particle size 0f 90 % less than 45 m.5.5 In-house alpha aluminium apparatus, prepared as follows (see 5.5.1 to 5.5.5). Necessary only if alpha aluminium standard (4.2.2) is to be prepared
25、in accordance with 6.1.5.5.1 Platinum dish and lid.5.5.2 Coarse filter paper.5.5.3 Drying oven, capable of being controlled at (105 5) C.5.5.4 Magnetic stirrer.5.5.5 Electric furnace, capable of being controlled at (1 300 50) C. Necessary only if the 100 % alpha alumina calibration standard (4.2.2)
26、is to be prepared in-house in accordance with 6.1.6 Procedure6.1 Preparation of 100 % alpha alumina calibration standardThe calibration standard shall be prepared as follows.a) Weigh out approximately 100 g of smelter grade alumina (4.2.2.2).b) Transfer to a 600 ml beaker and add 250 ml of hydrochlo
27、ric acid (4.2.2.1). Stir the solution at ambient temperature for 3 h using the magnetic stirrer (5.5.4).c) Filter the alumina slurry through a coarse filter paper (5.5.2). Wash the paper and the residue thoroughly three or four times with water to remove entrained hydrochloric acid.NOTE 1 This washi
28、ng procedure reduces the soda and other impurities in the alumina. Soda will react to form a beta alumina phase on calcining which will reduce the alpha phase content.d) Dry the alumina residue in the drying oven (5.5.3) at (105 5) C for 2 h. Transfer the dried alumina residue to a platinum dish (5.
29、5.1). Cover the dish with the platinum lid.e) Transfer the dish into the electric furnace (5.5.5) at 300 C. Raise the furnace temperature over a period of at least one hour to (1 300 50) C. Maintain at (1 300 50) C for 48 h.NOTE 2 Raising the temperature gradually will prevent the ejection of materi
30、al from the dish.f) Remove the dish from the furnace and allow to cool to room temperature. Transfer the 100 % alpha alumina calibration standard to a sealed container.2 ISO 2015 All rights reservedBS ISO 19950:2015ISO 19950:2015(E)6.2 Preparation of the test portion and calibration standardThe test
31、 portion and calibration standard shall be prepared as follows.a) Prepare a portion of the test sample of a suitable mass for the grinding mill (5.4) by using the riffle or rotary divider (5.3) in accordance with AS 4538.2. Take particular care to avoid loss of fine particles through dusting.b) Grin
32、d the test portion and if necessary the calibration standard, to a particle size of 90 % less than 45 m in the grinding mill (5.4).c) Prepare duplicate mounts of the test portion and the calibration standard for XRD analysis (see Note 2). A hydraulic press (5.2) may be used for this.d) Visually insp
33、ect each mount for imperfections such as cracks or areas with an uneven surface finish and discard if any imperfections can be seen. In this case prepare a new mount (see 6.2 c).NOTE 1 Commercially available, certified 100 % alpha alumina calibration standards typically have particle sizes less than
34、 45 m however in-house produced calibration standards will typically need to be ground.NOTE 2 Instructive information on sample preparation can be found in the References 1 and 2.6.3 MeasurementThe measurement procedure shall be as follows.a) Set the X-ray diffractometer (5.1) conditions for the det
35、ermination of alpha alumina phase (corundum) content.b) Typical diffractometer settings and 2 theta (2) angular scan settings are given in Table 1 and Table 2.c) Ensure that the scanning ranges and background positions are corrected for the actual 2 theta (2) diffractometer alignment.d) Measure the
36、integrated peak intensity and individual 2 background intensities to allow calculation of net peak area of the (012) and (116) reflections as per Clause 7 a), for each mount.e) Ensure a calibration standard (4.2) mount is measured at least at the beginning and end of each batch.Table 1 Typical diffr
37、actometer settingsExcitation radiation Co K1 Cu K1Tube voltage 40 kV 45 kVTube amperage 40 mA 40 mAMeasurement Fixed area method Fixed area methodTime per step 3 seconds 3 secondsStep size 0,02 0,02Background measurement time 6 seconds per peak 6 seconds per peak ISO 2015 All rights reserved 3BS ISO
38、 19950:2015ISO 19950:2015(E)Table 2 Typical 2 scan settingshkl d-spacing ()Theoretical peak position (2)aScanning range (2) Background (2)Cu K1 Co K1 Cu K1 Co K1 Cu K1 Co K1012 3,48 25,58 29,79 25,2 to 26,0 29,3 to 30,2 24,9 to 26,4 28,9 to 30,7116 1,60 57, 50 67,91 57.0 to 58,1 67,3 to 68,6 56,7 to
39、 58,4 66,9 to 68,9aThe alpha Al2O3(corundum) theoretical peak positions are from the ICDD file no 461212, year 2003 (see Reference 3).NOTE 1 The background 2 angle positions are outside the scanning ranges used to determine the integrated peak area. This is to ensure that for the 100 % alpha alumina
40、 calibration sample measurement, the background positions are clear of the very large alpha alumina peak.NOTE 2 Background intensities will be much higher for smelter grade aluminas than for 100 % alpha alumina calibration samples. This is due to the significant contribution to background from inter
41、mediate alumina phases in smelter grade aluminas.7 Calculation and expression of resultsThe alpha alumina content of each test sample shall be calculated separately from each of the two peaks (012) and (116) separately, as below. They are then averaged.a) Calculate the net integrated peak area, Inet
42、for each test portion from Formula (1):IIInetbp= (1)whereIpis the integrated peak intensity, i.e the sum of the individual step measurements, in cps;Ibis the integrated background intensity, in cps.Ibis calculated using:IIIbdiffstepbb=+221212(2)whereIb1is the intensity at the low-angle background po
43、sition b1, in cps;Ib2is the intensity at the high-angle background position b2, in cps;2diffis the scanning range, the difference between the 2 angle finish and start positions, in ;2stepis the scanning step size, in .b) Calculate the average intensity for the 100 % alpha alumina calibration standar
44、d, Inet(100),av, from Formula (3):4 ISO 2015 All rights reservedBS ISO 19950:2015ISO 19950:2015(E)IIninnetnet(av1001),=(3)whereInet,100net peak intensity in cps, for an individual calibration standard measurement, calculated as per Formula (1);n number of measurements carried out on the calibration
45、standards.c) Calculate the alpha content for each peak of each test portion, as a percentage by mass, from Formula (4):% alpha alumina(100),av=IInetnet100 (4)d) Average the alpha content for both peaks (012) and (116) of each test portion and express to the nearest integer.8 PrecisionA test program
46、to determine precision of the method was carried out in accordance with AS 28505by one analyst from each of eight different laboratories. Results of the interlaboratory test program are shown in Annex A. Four repetitions were carried out by each laboratory on each of four test samples of different r
47、efinery aluminas. The means, within-laboratory repeatability “r” and between-laboratory reproducibility “R” at the 95 % confidence level were calculated for the four samples. These are given in Table 3.Table 3 Alpha alumina results from test programSample ID Mean alumina content, %Repeatability rRep
48、roducibility RS-123 2,9 0,8 1,4S-124 24,5 0,8 2,9S-125 1,5 0,8 1,1S-126 9,2 1,2 1,8From this data, the overall precision expected of this method at the 95 % confidence level is given in Table 4. Note that reproducibility “R” was shown to be a function of the alpha content of the sample.Repeatability
49、 “r” was typically 0,8, but the “r” of 1,2 obtained for sample S-126 indicates a likely sample dependency for “r”. The S-126 sample was obtained by mixing two process streams (rotary calcined and flash calcined aluminas) from the same refinery. The other samples were from single process streams at other refineries.Table 4 Precision data for alpha alumina determinationRepeatability r Typically 0,8Reproducibility R R = 0,08 + 1,0Where “
