1、BSI Standards PublicationBS ISO 11258:2015Iron ores for shaft direct-reduction feedstocks Determination of thereducibility index, final degreeof reduction and degree ofmetallizationBS ISO 11258:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 11258:2015. It
2、supersedes BS ISO 11258:2007 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee ISE/58, Iron ores.A list of organizations represented on this committee can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 necessar
3、yprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 79293 9ICS 73.060.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was publ
4、ished under the authority of theStandards Policy and Strategy Committee on 30 September 2015.Amendments issued since publicationDate Text affectedBS ISO 11258:2015 ISO 2015Iron ores for shaft direct-reduction feedstocks Determination of the reducibility index, final degree of reduction and degree of
5、 metallizationMinerais de fer pour charges utilises dans les procds par rduction directe Dtermination de lindice de rductibilit, du degr final de rduction et du degr de mtallisationINTERNATIONAL STANDARDISO11258Third edition2015-08-15Reference numberISO 11258:2015(E)BS ISO 11258:2015ISO 11258:2015(E
6、)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 photocopying, or postin
7、g 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 11Fax +41 22 7
8、49 09 47copyrightiso.orgwww.iso.orgBS ISO 11258:2015ISO 11258:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Sampling, sample preparation, and preparation of test portions 25.1 Sampling and sample preparation . 25.2 Preparation of test po
9、rtions 26 Apparatus . 26.1 General . 27 Test conditions . 37.1 General . 37.2 Reducing gas . 37.2.1 Composition . 37.2.2 Purity . 37.2.3 Flow rate . 37.3 Heating and cooling gas 37.4 Temperature of the test portion . 48 Procedure. 48.1 Number of determinations for the test 48.2 Chemical analysis 48.
10、3 Reduction . 48.4 Chemical analysis after reduction 49 Expression of results 59.1 Calculation of the final degree of reduction (R90) 59.2 Calculation of the reducibility indices dR/dt(R=40) and dR/dt(R=90) . 59.2.1 Reduction curve 59.2.2 Reducibility index for 40 % reduction 59.2.3 Reducibility ind
11、ex for 90 % reduction 69.3 Calculation of the degree of metallization (M) 69.3.1 Determination of the degree of metallization from chemical analysis (M). 69.3.2 Determination of the degree of metallization from R90(MR) 69.4 Repeatability for R90and acceptance of test results 710 Test report . 711 Ve
12、rification . 7Annex A (normative) Flowsheet of the procedure for the acceptance of test results .11Annex B (informative) Derivation of formula for reducibility 12Annex C (informative) Derivation of formula for degree of metallization from R9014Bibliography .16 ISO 2015 All rights reserved iiiContent
13、s PageBS ISO 11258:2015ISO 11258:2015(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 bod
14、y 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 collaborates closely with the International Electrote
15、chnical 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 criteria needed for the different types of ISO
16、 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 of patent rights. ISO shall not be held resp
17、onsible 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 used in this document is information given
18、 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 Barriers to Trade (TBT) see the following
19、URL: Foreword - Supplementary informationThe committee responsible for this document is ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 3, Physical testing.This third edition cancels and replaces the second edition (ISO 11258:2007), of which it constitutes a minor revision to contempla
20、te the outcomes of the studies on mass definition, as well as minor editorial improvements.iv ISO 2015 All rights reservedBS ISO 11258:2015ISO 11258:2015(E)IntroductionThis International Standard concerns one of a number of physical test methods that have been developed to measure various physical p
21、arameters and to evaluate the behaviour of iron ores, including reducibility, disintegration, crushing strength, apparent density, etc. This method was developed to provide a uniform procedure, validated by collaborative testing, to facilitate comparisons of tests made in different laboratories.The
22、results of this test have to be considered in conjunction with other tests used to evaluate the quality of iron ores as feedstocks for direct reduction processes.This International Standard can be used to provide test results as part of a production quality control system, as a basis of a contract,
23、or as part of a research project. ISO 2015 All rights reserved vBS ISO 11258:2015BS ISO 11258:2015Iron ores for shaft direct-reduction feedstocks Determination of the reducibility index, final degree of reduction and degree of metallizationCAUTION This International Standard can involve hazardous op
24、erations and equipment. This International Standard does not purport to address all of the safety issues associated with its use. It is the responsibility of the user of this International Standard to establish appropriate safety and health practices and determine the applicability of regulatory lim
25、itations prior to its use.1 ScopeThis International Standard specifies a method to provide a relative measure for evaluating the extent to and ease to which oxygen can be removed from iron ores, when reduced under conditions resembling those prevailing in shaft direct-reduction processes. It specifi
26、es the determination of the reducibility, final degree of reduction, and degree of metallization.This International Standard is applicable to lump ores and hot-bonded pellets.2 Normative referencesThe following documents, in whole or in part, are normatively referenced in this document and are indis
27、pensable 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 2597-1, Iron ores Determination of total iron content Part 1: Titrimetric method after tin(II) chloride red
28、uctionISO 2597-2, Iron ores Determination of total iron content Part 2: Titrimetric methods after titanium(III) chloride reductionISO 3082, Iron ores Sampling and sample preparation proceduresISO 5416, Direct reduced iron Determination of metallic iron Bromine-methanol titrimetric methodISO 9035, Ir
29、on ores Determination of acid-soluble iron(II) content Titrimetric methodISO 11323, Iron ore and direct reduced iron Vocabulary3 Terms and definitionsFor the purposes of this document, the terms and definitions given in ISO 11323 apply.4 PrincipleThe test portion is isothermally reduced in a fixed b
30、ed, at 800 C, using a reducing gas consisting of H2,CO, CO2, and N2, and is weighed continuously or at specified time intervals until 90 min of reduction is reached. The rate of reduction is calculated at the oxygen/iron ratio of 0,9 and the final degree of reduction is calculated from the oxygen ma
31、ss loss after 90 min (R90). The degree of metallization is calculated either by a formula based on R90or by chemical analysis of the reduced product.INTERNATIONAL STANDARD ISO 11258:2015(E) ISO 2015 All rights reserved 1BS ISO 11258:2015ISO 11258:2015(E)5 Sampling, sample preparation, and preparatio
32、n of test portions5.1 Sampling and sample preparationSampling of a lot and preparation of a test sample shall be in accordance with ISO 3082.The size range for pellets shall be 50 % - 16,0 mm + 12,5 mm and 50 % - 12,5 mm + 10,0 mm.The size range for lump ores shall be 50 % - 20,0 mm + 16,0 mm and 50
33、 % - 16,0 mm + 10,0 mm.A test sample of at least 2,5 kg, on dry basis, of the sized material shall be obtained.Oven-dry the test sample to constant mass at 105 C 5 C and cool it to room temperature before preparation of the test portions.NOTE Constant mass is achieved when the difference in mass bet
34、ween two subsequent measurements becomes less than 0,05 % of the initial mass of the test sample.5.2 Preparation of test portionsCollect each test portion by taking ore particles at random.NOTE Manual methods of division recommended in ISO 3082, such as riffling, can be applied to obtain the test po
35、rtions.At least five test portions, each of approximately 500 g ( the mass of 1 particle) shall be prepared from the test sample: four test portions for testing and one for chemical analysis.Weigh the test portions to the nearest 1 g and register the mass of each test portion on its recipient label.
36、6 Apparatus6.1 GeneralThe test apparatus shall comprise the following:a) ordinary laboratory equipment, such as an oven, hand tools, and safety equipment;b) reduction-tube assembly;c) furnace, equipped with a balance for permitting the mass loss of the test portion to be read at any time during the
37、test;d) system to supply the gases and regulate the flow rates;e) weighing device.Figure 1 shows an example of the test apparatus.6.2 Reduction tube, made of non-scaling, heat-resistant metal to withstand temperatures higher than 800 C and resistant to deformation.The internal diameter shall be 75 m
38、m 1 mm. A removable perforated plate, made of non-scaling, heat-resistant metal to withstand temperatures higher than 800 C shall be mounted in the reduction tube to support the test portion and to ensure uniform gas flow through it. The perforated plate shall be 4 mm thick, with its diameter 1 mm l
39、ess than the internal diameter of the tube. The holes in the plate shall be 2 mm to 3 mm in diameter at a pitch centre distance of 4 mm to 5 mm.Figure 2 shows an example of a reduction tube.2 ISO 2015 All rights reservedBS ISO 11258:2015ISO 11258:2015(E)6.3 Furnace, having a heating capacity and tem
40、perature control able to maintain the entire test portion, as well as the gas entering the bed, at 800 C 5 C.6.4 Balance, capable of weighing the reduction tube assembly, including the test portion, to an accuracy of 1 g. The balance shall have an appropriate device to suspend the reduction tube ass
41、embly.6.5 Gas-supply system, capable of supplying the gases and regulating gas flow rates.It shall be ensured that a frictionless connection between the gas-supply system and the reduction tube does not affect the weight loss determination during reduction.6.6 Weighing device, capable of weighing th
42、e test sample and test portions to an accuracy of 1 g.7 Test conditions7.1 GeneralVolumes and flow rates of gases used are as measured at a reference temperature of 0 C and at a reference atmospheric pressure of 101,325 kPa (1,013 25 bar).7.2 Reducing gas7.2.1 CompositionThe reducing gas shall consi
43、st of the following:CO 30 % 1 % (volume fraction)CO215 % 1 % (volume fraction)H245 % 1 % (volume fraction)N210 % 1 % (volume fraction)7.2.2 PurityImpurities in the reducing gas shall not exceed the following:O20,1 % (volume fraction)H2O 0,2 % (volume fraction)7.2.3 Flow rateThe flow rate of the redu
44、cing gas, during the entire reducing period, shall be maintained at 50 L/min 0,5 L/min.7.3 Heating and cooling gasNitrogen (N2) shall be used as the heating and cooling gas. Impurities shall not exceed 0,1 % (volume fraction).The flow rate of N2shall be maintained at 25 L/min until the test portion
45、reaches 800 C and at 50 L/min during temperature-equilibration period. During cooling, it shall be maintained at 25 L/min. ISO 2015 All rights reserved 3BS ISO 11258:2015ISO 11258:2015(E)7.4 Temperature of the test portionThe temperature of the entire test portion shall be maintained at 800 C 5 C du
46、ring the entire reducing period and, as such, the reducing gas shall be preheated before entering the test portion.8 Procedure8.1 Number of determinations for the testCarry out the test as many times as required by the procedure in Annex A.8.2 Chemical analysisTake, at random, one of the test portio
47、ns prepared in 5.2 and use it for the determination of the iron(II) oxide content (w1) in accordance with ISO 9035 and the total iron content (w2) in accordance with ISO 2597-1 or ISO 2597-2.8.3 ReductionTake, at random, another test portion prepared in 5.2 and record its mass (m0). Place it in the
48、reduction tube (6.2) and level its surface.NOTE In order to achieve a more uniform gas flow, a double-layer bed of porcelain balls sized between 10,0 mm and 12,5 mm can be placed between the perforated plate and the test portion.Close the top of the reduction tube. Connect the thermocouple, ensuring
49、 that its tip is in the centre of the test portion, as shown in Figure 1.Insert the reduction tube into the furnace (6.3) and suspend it centrally from the balance (6.4), ensuring that there is no contact with the furnace wall or heating elements.Connect the gas-supply system (6.5).Pass a flow of N2through the test portion at a rate of at least 25 L/min 0,5 L/min and commence heating. When the temperature of the test portion approaches 800 C, increase the flow rate to 50 L/min 0,5 L/min.
