1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS ISO 3087:2011Iron ores Determination ofthe moisture content of a lotBS ISO 3087:2011 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 308
2、7:2011. Itsupersedes BS ISO 3087:1998 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee ISE/58, Iron ores.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the
3、 necessaryprovisions of a contract. Users are responsible for its correctapplication. BSI 2011ISBN 978 0 580 66541 7ICS 73.060.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy
4、 Committee on 31 October 2011.Amendments issued since publicationDate Text affectedBS ISO 3087:2011Iron ores Determination of the moisture content of a lotMinerais de fer Dtermination de lhumidit dun lot ISO 2011Reference numberISO 3087:2011(E)Fourth edition2011-10-01ISO3087INTERNATIONAL STANDARDBS
5、ISO 3087:2011ISO 3087:2011(E)COPYRIGHT PROTECTED DOCUMENT ISO 2011All 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 writing from
6、 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-mail copyrightiso.orgWeb www.iso.orgPublished in Switzerlandii ISO 2011 All rights reservedBS ISO 3087:2011ISO 3087:2
7、011(E)Contents PageForeword ivIntroduction v1 Scope 12 Normative references .13 Terms and definitions .14 Principle .15 Apparatus 16 Samples .17 Procedure 27.1 Number of moisture measurements .27.2 Measurement 28 Verification 39 Calculation and expression of results .49.1 Test portion .49.2 Lot 410
8、Test report .5Annex A (normative) Determination of moisture content of adhesive or wet iron ores 7Annex B (normative) Corrections for sprinkled water and/or rainwater .9Annex C (informative) Precision of moisture measurement .14Annex D (informative) Examples of test reports 15 ISO 2011 All rights re
9、served iiiBS ISO 3087:2011ForewordISO (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 i
10、n 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 collaborates closely with the International Electrotechnical Commis
11、sion (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 Standards. Draft International Standards adopted by the technical c
12、ommittees 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 this document may be the subject of patent rights. ISO shall no
13、t be held responsible for identifying any or all such patent rights.ISO 3087 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 1, Sampling.This fourth edition cancels and replaces the third edition (ISO 3087:1998), which has been technically revised.IS
14、O 3087:2011(E)iv ISO 2011 All rights reservedBS ISO 3087:2011IntroductionCurrently, large tonnages of iron ore are traded internationally and a small error in the measured moisture content mass fraction (%) of a lot has a considerable effect on the commercial transaction. The correct determination o
15、f moisture content of a lot is, therefore, a matter of importance for both the purchaser and the vendor.This International Standard does not address the determination of the hygroscopic moisture content of a test sample for chemical analysis. If the hygroscopic moisture content is required to be det
16、ermined, reference should be made to ISO 2596:2006, Iron ores Determination of hygroscopic moisture in analytical samples Gravimetric, Karl Fischer and mass-loss methods.ISO 3087:2011(E) ISO 2011 All rights reserved vBS ISO 3087:2011BS ISO 3087:2011INTERNATIONAL STANDARD ISO 3087:2011(E)Iron ores De
17、termination of the moisture content of a lot1 ScopeThis International Standard specifies a method for the determination of the moisture content of a lot of iron ore. This method is applicable to all iron ores, whether natural or processed.2 Normative referencesThe following referenced documents are
18、indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 3082, Iron ores Sampling and sample preparation proceduresISO 11323, Iron ore and dir
19、ect reduced iron Vocabulary3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 11323 apply.4 PrincipleDry the test portion in air at 105 C to constant mass and measure the loss in mass. Express the moisture content as the mass loss relative to the origina
20、l mass of the sample as a mass fraction (%).5 Apparatus5.1 Drying pan, with a smooth surface, free from contamination and capable of accommodating the specified quantity of a test portion in a layer of nominal thickness not greater than 31,5 mm.5.2 Drying oven, equipped with a temperature indicator
21、and control apparatus capable of regulating the temperature at any point in the oven at 105 C null 5 C and so designed as to maintain this temperature with a current of air to ensure efficient drying but without any loss of sample, and fitted with a fan that allows for both the circulation and chang
22、e of air.5.3 Weighing device, accurate to at least 0,05 % of the initial mass of a test portion.The capacity of the weighing device shall be enough for the initial mass of the test portion.6 SamplesTest samples which have been taken and prepared in accordance with ISO 3082 shall be used. The mass of
23、 a test portion, in relation to its nominal top size, is specified in Table 1, in accordance with ISO 3082. ISO 2011 All rights reserved 1BS ISO 3087:2011Table 1 Minimum mass of test portionNominal top size of test portion Minimum mass of test portionmm kgover up to and including 22,4 31,5 1010,0 22
24、,4 5 10,0 17 Procedure7.1 Number of moisture measurementsCarry out one moisture measurement per test portion on the number of test portions specified in Table 2, according to the conditions of preparation of the test sample.Table 2 Number of test portionsPreparation of test sample Number of partial
25、samples per lot Number of test portions to be testedFrom gross sample 4 per gross sampleFrom partial sample2 4 per partial sample3 to 7 2 minimum per partial samplenull 8 1 minimum per partial sampleFrom increment 1 minimum per incrementIn order to minimize losses of moisture to the atmosphere, it i
26、s necessary to perform all the initial weighings of the test portions as quickly as possible after obtaining those test portions.7.2 Measurement7.2.1 GeneralThe moisture determination shall be measured in accordance with 7.2.2 or, alternatively, for ores with 8 % or more of combined water in accorda
27、nce with 7.2.3.When it is difficult to conduct sieving, crushing and dividing, owing to a sample being adhesive or excessively wet, the sample may be predried in accordance with the procedure in Annex A.7.2.2 Normal methoda) Spread the test portion in a layer of nominal thickness not greater than 31
28、,5 mm in the tared drying pan (5.1) and determine the total mass immediately. Record the total mass, the mass of the drying pan, the initial mass of the test portion (null1) and the numerical value of 0,05 % of the initial mass of the test portion.b) Place the drying pan with the test portion in the
29、 drying oven (5.2) set at 105 C, and maintain this temperature for not less than 4 h. Remove the drying pan with the test portion from the drying oven and weigh it immediately while still hot in order to minimize any reabsorption of moisture. Alternatively, weigh the test portion after cooling in ai
30、r in a container having a close-fitting airtight lid. In each case, report the method of weighing.c) Once more, place the drying pan with the test portion in the drying oven, heat for a further 1 h, and then repeat the weighing.ISO 3087:2011(E)2 ISO 2011 All rights reservedBS ISO 3087:2011d) Repeat
31、the procedure described in the previous item until the difference in mass between subsequent measurements becomes 0,05 % or less of the initial mass of the test portion.NOTE 1 The weighing device should be protected from the influence of heat.NOTE 2 Drying times will be dependent on the type of ore
32、under test. For a series of measurements carried out on a particular type of ore, the drying time of the test portion may be specified by check experiments carried out beforehand.NOTE 3 To reduce drying time, a lower layer-thickness of the sample is recommended. It should be specified by check exper
33、iments carried out beforehand.NOTE 4 For convenience, the test portion of mass 10 kg for ore of particle size less than 31,5 mm may be divided into two portions, each of which is subjected to moisture measurement. In calculating the results, the mean of the two values of initial mass and the mean of
34、 the two values of the drying loss in mass should be used.7.2.3 Method for ores of high combined water contentFor ores containing 8 % or more combined water, the following procedure may be applied.a) Spread the test portion in a layer of nominal thickness not greater than 31,5 mm in the tared drying
35、 pan (5.1) and determine the total mass immediately. Record the total mass, the mass of the drying pan and the initial mass of the test portion (null1).b) Place the drying pan with the test portion in the drying oven (5.2) set at 105 C and maintain this temperature for not less than 24 h. Remove the
36、 drying pan with the test portion from the drying oven and weigh it immediately while still hot in order to minimize any reabsorption of moisture. Alternatively, weigh the test portion after cooling in air in a container having a close-fitting airtight lid. Record the total mass after drying. In eac
37、h case, report the method of weighing.NOTE The notes in 7.2.2 apply to this subclause.8 VerificationRegular checking of apparatus and procedures is essential to verify the test results. Checks shall be carried out prior to the commencement of a routine test in accordance with this International Stan
38、dard and at regular intervals thereafter. The frequency of checking is a matter for each laboratory to determine. A detailed record of all verification activities shall be maintained for the following items:a) Sprinkled water measurement v olumenometer;b) Rainfall measurement r ain gauge;c) Moisture
39、 test o ven temperature/temperature regulation; c irculation and change of air in oven; w eighing device.ISO 3087:2011(E) ISO 2011 All rights reserved 3BS ISO 3087:20119 Calculation and expression of results9.1 Test portionThe result of the determination of the moisture content, wnull, expressed as
40、a mass fraction (%), for each test portion, is given by Equation (1) and reported to the second decimal place.wmmmi=121100 (1)wherenull1is the initial mass, in grams, of the test portion;null2is the mass, in grams, of the test portion after drying.9.2 LotThe moisture content of a lot is given by one
41、 of the Equations (2) to (5) as the occasion may demand, and reported to the first decimal place.Sprinkled water and/or rainwater over iron ore during loading and/or unloading operation shall be corrected according to the procedure specified in Annex B.9.2.1 When moisture determination is conducted
42、on the gross sample from the lot, the moisture of the lot is determined as follows.When the range of the four test results does not exceed 1,3null as given in Table 3, the arithmetic mean, w , of the four results shall be the moisture content, expressed as a mass fraction (%), of the lot as given by
43、 Equation (2).wwwww=+123 44(2)where w1, w2, w3and w4are the results of the determinations of the moisture contents, expressed as a mass fraction (%), on each of the four test portions.When the range of the four test results exceeds 1,3null as given in Table 3, the median shall be taken as the moistu
44、re content of the lot. The median of four test results is defined as the mean of the two non-extreme test results.Table 3 Repeatability limit of moisture determination on the gross sampleAverage of moisture contentwmass fraction (%)Repeatability limitnullamass fraction (%)Repeatability limit1,3nullm
45、ass fraction (%)w null 3 0,20 0,2636w 0,25 0,336 null w 0,31 0,40aThe theoretical background of the repeatability limit is shown in Annex C.9.2.2 When mass-basis sampling has been performed and moisture determination is conducted on each partial sample, the weighted mean, w , of the results from all
46、 the partial samples, considering the number of increments for each partial sample, shall be the moisture content, expressed as a mass fraction (%), of the lot, as given by Equation (3).ISO 3087:2011(E)4 ISO 2011 All rights reservedBS ISO 3087:2011wNwNiiikiik=11(3)wherenull is the number of partial
47、samples;nullnullis the number of increments in the nullth partial sample;wnullis the result of the determination of the moisture content, expressed as a mass fraction (%), of the nullth partial sample, according to Table 2 using as the number of test portions either 4 or 2.If it is impracticable to
48、sample the lot as a whole, or desirable to sample a lot in separate parts of unequal mass as in the case of time-basis sampling, the moisture content of each part shall be determined independently and the weighted mean, w , of the results, expressed as a mass fraction (%), of the lot calculated from
49、 the individual results using Equation (4).wmwmiiikiik=11(4)wherenull is the number of partial samples;nullnullis the mass of the nullth part;wnullis the result of the determination of the moisture content, expressed as a mass fraction (%), of the nullth part.9.2.3 When moisture determination is conducted on each increment, the arithmetic mean, w , of the results for all increments obtained according to 9.1 shall be the moisture content, expressed as a mass fraction (%), of the lot as given by Equation
