1、BSI Standards PublicationBS ISO 11256:2015Iron ore pellets for shaftdirect-reduction feedstocks Determination of the clusteringindexBS ISO 11256:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 11256:2015. Itsupersedes BS ISO 11256:2007 which is withdrawn.T
2、he 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 responsible
3、for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 79292 2ICS 73.060.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy
4、and Strategy Committee on 31 August 2015.Amendments issued since publicationDate Text affectedBS ISO 11256:2015 ISO 2015Iron ore pellets for shaft direct-reduction feedstocks Determination of the clustering indexBoulettes de minerais de fer pour charges utilises dans les procds par rduction directe
5、Dtermination du pouvoir collantINTERNATIONAL STANDARDISO11256Third edition2015-08-01Reference numberISO 11256:2015(E)BS ISO 11256:2015ISO 11256:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no par
6、t 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 member bo
7、dy 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 11256:2015ISO 11256:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitio
8、ns . 14 Principle 15 Sampling, sample preparation, and preparation of test portions 15.1 Sampling and sample preparation . 15.2 Preparation of test portion . 26 Apparatus . 27 Test conditions . 37.1 General . 37.2 Reducing gas . 37.2.1 Composition . 37.2.2 Purity . 47.2.3 Flow rate . 47.3 Heating an
9、d cooling gas 47.4 Temperature of the test portion . 47.5 Loading of the test portion . 48 Procedure. 48.1 Number of determinations for the test 48.2 Chemical analysis 48.3 Reduction . 48.4 Disaggregation 59 Expression of results 69.1 Calculation of the clustering index (CI) . 69.2 Repeatability and
10、 acceptance of test results . 610 Test report . 611 Verification . 6Annex A (normative) Flowsheet of the procedure for the acceptance of test results .11Annex B (informative) Example of a calculation of the clustering index .12 ISO 2015 All rights reserved iiiContents PageBS ISO 11256:2015ISO 11256:
11、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 whi
12、ch 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 Commission (IEC) on all m
13、atters 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 documents should be noted. This
14、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 responsible for identifying any or al
15、l 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 for the convenience of users and
16、 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 URL: Foreword - Supplementary inf
17、ormationThe 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 11256:2007), of which it constitutes a minor revision to contemplate the outcomes of the studies on
18、 mass definition and minor editorial improvements.iv ISO 2015 All rights reservedBS ISO 11256:2015ISO 11256:2015(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 o
19、f 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 results of this test have to be considered
20、 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, or as part of a research project. ISO 2015
21、 All rights reserved vBS ISO 11256:2015BS ISO 11256:2015Iron ore pellets for shaft direct-reduction feedstocks Determination of the clustering indexCAUTION This International Standard may involve hazardous operations and equipment. This International Standard does not purport to address all of the s
22、afety 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 limitations prior to its use.1 ScopeThis International Standard specifies a method to provide a
23、 relative measure for evaluating the formation of clusters of iron ore pellets when reduced under conditions resembling those prevailing in shaft direct-reduction processes.This International Standard is applicable to hot-bonded pellets.2 Normative referencesThe following documents, in whole or in p
24、art, 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 total iron
25、 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 acid-solu
26、ble 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 850 C under static load usin
27、g a reducing gas consisting of H2,CO, CO2, and N2until a degree of reduction of 95 % is obtained. The reduced test portion (cluster) is disaggregated by tumbling using a specific tumble drum. The clustering index is calculated as the mass of clustered material accumulated after specified disaggregat
28、ion operations.5 Sampling, sample preparation, and preparation 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.INTERNAT
29、IONAL STANDARD ISO 11256:2015(E) ISO 2015 All rights reserved 1BS ISO 11256:2015ISO 11256:2015(E)A test sample of at least 10 kg, on a dry basis, of sized pellets 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 p
30、ortions.NOTE Constant mass is achieved when the difference in mass between two subsequent measurements becomes less than 0,05 % of the initial mass of the test sample.5.2 Preparation of test portionCollect each test portion by taking ore particles at random.NOTE Manual methods of division recommende
31、d in ISO 3082, such as riffling, can be applied to obtain the test portions.At least five test portions, each of approximately 2 000 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 near
32、est 1 g and register the mass of each test portion on its recipient label.6 Apparatus6.1 GeneralThe test apparatus shall comprise the following:a) ordinary laboratory equipment such as an oven, hand tools, a time-control device, and safety equipment;b) a reduction tube assembly including a loading d
33、evice;c) a furnace equipped with a balance for permitting the mass loss of the test portion to be read at any time during the test;d) a system to supply the gases and regulate the flow rates;e) a tumble drum;f) a weighing device.Figure 1 shows an example of the test apparatus.6.2 Reduction tube, wit
34、h a double wall made of non-scaling, heat-resistant metal to withstand temperatures higher than 850 C and resistant to deformation. The internal diameter of the inner reduction tube shall be 125 mm 1 mm. A removable perforated plate made of non-scaling, heat-resistant metal to withstand temperatures
35、 higher than 850 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 10 mm thick with diameter 1 mm less than the internal diameter of the tube. The holes in the plate shall be 3 mm to 4 mm in diameter at a pit
36、ch centre distance of 5 mm to 6 mm. The internal diameter of the outer reduction tube shall be large enough to allow gas flow preheating before entering the inner reduction tube.Figure 2 shows an example of a reduction tube.6.3 Loading device, capable of supplying a total static load of 147 kPa 2 kP
37、a evenly to the test portion. The load shall be transferred by means of a ram with rigid perforated foot plate so as to distribute it evenly to the surface of the porcelain balls placed on top of the test portion. The foot plate shall be 10 mm thick and its diameter shall be 1 mm less than the inter
38、nal diameter of the tube. The holes in the plate shall be 3 mm to 4 mm in diameter at a pitch centre distance of 5 mm to 6 mm.6.4 Porcelain balls, having a size range between 10,0 mm and 12,5 mm and of sufficient quantity to form two double-layer beds on the perforated plate.2 ISO 2015 All rights re
39、servedBS ISO 11256:2015ISO 11256:2015(E)6.5 Furnace, having a heating capacity and temperature control able to maintain the entire test portion as well as the gas entering the test portion at 850 C 5 C.6.6 Balance, capable of weighing the reduction tube assembly, including the test portion, to an ac
40、curacy of 1 g. The balance shall have an appropriate device to suspend the reduction tube assembly.6.7 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 aff
41、ect the weight loss determination during reduction.6.8 Tumble drum, made of steel plate at least 5 mm thickness, having an internal diameter of 1 000 mm, and an internal length of 500 mm. Two equally spaced L-shaped steel lifters 50 mm flat 50 mm high 5 mm thick and 500 mm long shall be solidly atta
42、ched longitudinally inside the drum by welding so as to prevent the accumulation of material between lifter and drum. Each lifter shall be fastened so that it points towards the axis of the drum with its attached leg pointing away from the direction of rotation, thus providing a clear unobstructed s
43、helf for lifting the sample. The door shall be so constructed as to fit into the drum to form a smooth inner surface. During the test, the door shall be rigidly fastened and sealed to prevent loss of the sample. The drum shall be rotated on stub axles attached to its ends by flanges welded so as to
44、provide smooth inner surfaces. The drum shall be replaced in any case when the thickness of the plate is reduced to 3 mm in any area. The lifters shall be replaced when the height of the shelf is reduced to less than 47 mm.Figure 3 shows an example of a tumble drum.6.9 Drum rotation equipment, capab
45、le of ensuring that the drum attains full speed in one revolution, rotates at a constant speed of 25 r/min 1 r/min, and stops within one revolution. The equipment shall be fitted with a revolution counter and with an automatic device for stopping the drum after a predetermined number of revolutions.
46、6.10 Weighing device, capable of 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 (1,01 325 bar).7.2 Reducing gas7
47、.2.1 CompositionThe reducing gas shall consist of the following:CO 30,0 % 1,0 % (volume fraction);CO215,0 % 1,0 % (volume fraction);H245,0 % 1,0 % (volume fraction);N210,0 % 1,0 % (volume fraction). ISO 2015 All rights reserved 3BS ISO 11256:2015ISO 11256:2015(E)7.2.2 PurityImpurities in the reducin
48、g gas shall not exceed the following:O20,1 % (volume fraction);H2O 0,2 % (volume fraction).7.2.3 Flow rateThe flow rate of the reducing gas during the entire reducing period shall be maintained at 40 L/min 0,5 L/min.7.3 Heating and cooling gasNitrogen (N2) shall be used as the heating and cooling ga
49、s. Impurities shall not exceed 0,1 % (volume fraction).The flow rate of N2shall be maintained at 20 L/min until the test portion reaches 850 C and at 40 L/min during temperature-equilibration period. During cooling, it shall be maintained at 20 L/min.7.4 Temperature of the test portionThe temperature of the entire test portion shall be maintained at 850 C 5 C during the entire reducing period and as such, the reducing gas shall be preheated before entering the test portion.7.5 Loading of the tes
