1、BSI Standards PublicationBS ISO 4695:2015Iron ores for blast furnacefeedstocks Determination ofthe reducibility by the rate ofreduction indexBS ISO 4695:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 4695:2015. Itsupersedes BS ISO 4695:2007 which is withd
2、rawn.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 necessaryprovisions of a contract. Users are respon
3、sible for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 79289 2ICS 73.060.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards P
4、olicy and Strategy Committee on 31 August 2015.Amendments issued since publicationDate Text affectedBS ISO 4695:2015 ISO 2015Iron ores for blast furnace feedstocks Determination of the reducibility by the rate of reduction indexMinerais de fer pour charges de hauts fourneaux Dtermination de la rduct
5、ibilit partir de la vitesse de rductionINTERNATIONAL STANDARDISO4695Fourth edition2015-08-15Reference numberISO 4695:2015(E)BS ISO 4695:2015ISO 4695:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, n
6、o part of this 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 memb
7、er 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 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 4695:2015ISO 4695:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and defini
8、tions . 14 Principle 15 Sampling, sample preparation and preparation of test portions 15.1 Sampling and sample preparation . 15.2 Preparation of test portions 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 . 3
9、7.3 Heating and cooling gas 37.4 Temperature of the test portion . 38 Procedure. 48.1 Number of determinations for the test 48.2 Chemical analysis 48.3 Reduction . 49 Expression of results 59.1 Calculation of the reducibility index 59.2 Repeatability and acceptance of test results . 510 Test report
10、. 611 Verification . 6Annex A (normative) Flowsheet of the procedure for the acceptance of test results .10Annex B (informative) Derivation of equation for reducibility .11 ISO 2015 All rights reserved iiiContents PageBS ISO 4695:2015ISO 4695:2015(E)ForewordISO (the International Organization for St
11、andardization) 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 which a technical committee has been established has the rig
12、ht 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 Commission (IEC) on all matters of electrotechnical standardization.The procedures
13、 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 documents should be noted. This document was drafted in accordance with the editorial rul
14、es 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 responsible for identifying any or all such patent rights. Details of any patent rights identi
15、fied 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 for the convenience of users and does not constitute an endorsement.For an explanation on
16、 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 URL: Foreword - Supplementary informationThe committee responsible for this document is IS
17、O/TC 102, Iron ore and direct reduced iron, Subcommittee SC 3, Physical testing.This fourth edition cancels and replaces the third edition (ISO 4695:2007), of which it constitutes a minor revision to contemplate the outcomes of the studies on mass definition, as well as minor editorial improvements.
18、iv ISO 2015 All rights reservedBS ISO 4695:2015ISO 4695:2015(E)IntroductionThis International Standard concerns one of a number of physical test methods that have been developed to measure various physical parameters and to evaluate the behaviour of iron ores, including reducibility, disintegration,
19、 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 results of this test have to be considered in conjunction with other tests used to evaluate t
20、he quality of iron ores as feedstocks for blast furnace 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, or as part of a research project. ISO 2015 All rights reserved vBS ISO 4695:2015BS ISO 4695:2015
21、Iron ores for blast furnace feedstocks Determination of the reducibility by the rate of reduction indexCAUTION This International Standard can involve hazardous operations and equipment. This International Standard does not purport to address all of the safety issues associated with its use. It is t
22、he responsibility of the user of this International Standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to its use.1 ScopeThis International Standard specifies a method to provide a relative measure for evaluating the extent t
23、o and ease with which oxygen can be removed from iron ores, when reduced under conditions resembling those prevailing in the reduction zone of a blast furnace.This International Standard is applicable to lump ores, sinters and hot-bonded pellets.2 Normative referencesThe following documents, in whol
24、e or in part, are normatively 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.ISO 2597-1, Iron ores Determination of t
25、otal iron content Part 1: Titrimetric method after tin(II) chloride reductionISO 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 9035, Iron ores Determination of
26、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 bed, at 950 C, using a red
27、ucing gas consisting of CO and N2, and the mass loss of the test portion is recorded continuously or at specified time intervals until its degree of reduction reaches 65 %. The rate of reduction is calculated at the oxygen/iron ratio of 0,9.5 Sampling, sample preparation and preparation of test port
28、ions5.1 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, sinters and lump ores shall be -12,5 mm + 10,0 mm.INTERNATIONAL STANDARD ISO 4695:2015(E) ISO 2015 All rights reserved 1BS ISO 4695:2015ISO 4695:
29、2015(E)A test sample of at least 2,5 kg, on a 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 between two subse
30、quent 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 portions.At leas
31、t five test portions, each of approximately 500 g ( the mass of one 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.6 Apparatus6
32、.1 General The test apparatus shall comprise the following:a) ordinary laboratory equipment, such as an oven, hand tools, a time-control device 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
33、during the 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 950 C and resistant to deformation. The internal diameter s
34、hall be 75 mm 1 mm. A removable perforated plate, made of non-scaling, heat-resistant metal to withstand temperatures higher than 950 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 di
35、ameter 1 mm less 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 m.Figure 2 shows an example of a reduction tube.6.3 Furnace, having a heating capacity and temperature control able to maintain the entire test po
36、rtion, as well as the gas entering the bed, at 950 C 10 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 assembly.2 ISO 2015 All rights reservedBS ISO 4695:201
37、5ISO 4695:2015(E)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
38、 weighing the 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
39、 shall consist ofCO 40,0 % 0,5 % (volume fraction)N260,0 % 0,5 % (volume fraction)7.2.2 PurityImpurities in the reducing gas shall not exceed the following:H20,2 % (volume fraction)CO20,2 % (volume fraction)O20,1 % (volume fraction)H2O 0,2 % (volume fraction)7.2.3 Flow rateThe flow rate of the reduc
40、ing 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 r
41、eaches 950 C, and at 50 L/min during the temperature-equilibration period. During cooling, it shall be maintained at 5 L/min.7.4 Temperature of the test portionThe temperature of the entire test portion shall be maintained at 950 C 10 C during the entire reducing period and, as such, the reducing ga
42、s shall be preheated before entering the test portion. ISO 2015 All rights reserved 3BS ISO 4695:2015ISO 4695:2015(E)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 port
43、ions 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 portion prepared in 5.2 and record its mass (m0). Place it in the red
44、uction 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 th
45、at 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 N2thro
46、ugh the test portion at a rate of 25 L/min and commence heating. When the temperature of the test portion approaches 950 C, increase the flow rate to 50 L/min. Continue heating while maintaining the flow of N2, until the balance reading is constant and the temperature is constant at 950 C 10 C for 1
47、5 min.DANGER Carbon monoxide and the reducing gas, which contains carbon monoxide, are toxic and therefore hazardous. Testing shall be carried out in a well-ventilated area or under a hood. Precautions should be taken for the safety of the operator, in accordance with the safety codes of each countr
48、y.Tare the balance, start the time control device and immediately introduce the reducing gas at a flow rate of 50 L/min 0,5 L/min to replace the N2. Record the mass loss of the test portion (mt) at least every 3 min for the first 15 min and thereafter at 10 min intervals.Calculate the degree of redu
49、ction, Rt, relative to the iron(III) state, after t min, as follows:Rwwmmwtt=0,111 0,430 +0,430 100 100120 2(1)wherem0is the mass, in grams, of the test portion;mtis the mass loss, in grams, of the test portion after reduction time t;w1is the iron(II) oxide content, as a percentage by mass, of the test sample prior to the test, determined in accordance with ISO 9035; it is calculated from the iron(II) content by mul-tiplying it by the oxide conversion factor FeO/Fe(II) = 1,286
