1、BSI Standards PublicationBS ISO 7992:2015Iron ores for blast furnacefeedstocks Determination ofreduction under loadBS ISO 7992:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 7992:2015. Itsupersedes BS ISO 7992:2007 which is withdrawn.The UK participation
2、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 for its correctappli
3、cation. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 79291 5ICS 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 Committ
4、ee on 31 August 2015.Amendments issued since publicationDate Text affectedBS ISO 7992:2015 ISO 2015Iron ores for blast furnace feedstocks Determination of reduction under loadMinerais de fer pour charges de hauts fourneaux Dtermination de la rduction sous chargeINTERNATIONAL STANDARDISO7992Third edi
5、tion2015-08-01Reference numberISO 7992:2015(E)BS ISO 7992:2015ISO 7992:2015(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
6、 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 body in the country of the requester.ISO copyright officeCh. de Blandonnet
7、8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 7992:2015ISO 7992:2015(E)Foreword ivIntroduction v1 Scope . 12 Normative references 13 Terms and definitions . 14 Principle 15 Sampling, sample preparation and preparation of test p
8、ortions 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 . 37.3 Heating and cooling gas 47.4 Temperature of the test portion . 47.5 Load
9、ing of the test portion . 48 Procedure. 48.1 Number of determinations for the test 48.2 Chemical analysis 48.3 Reduction . 49 Expression of results 59.1 Preparation of the reduction curve . 59.2 Calculation of the differential pressure at 80 % reduction (p80) . 59.3 Calculation of the change in the
10、height of the test bed at 80 % reduction (h80) 69.4 Repeatability and 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) Derivation of equation for reducibility .12 ISO 2015 All
11、 rights reserved iiiContents PageBS ISO 7992:2015ISO 7992:2015(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 co
12、mmittees. 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 ISO, also take part in the work. ISO collaborates closely with th
13、e 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, Part 1. In particular the different approval criteria needed for t
14、he 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 elements of this document may be the subject of patent rights.
15、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 received (see www.iso.org/patents). Any trade name used in this do
16、cument 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 adherence to the WTO principles in the Technical Barriers to Tra
17、de (TBT) see the following 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 7992:2007), of which it constitutes a m
18、inor revision to contemplate the outcomes of the studies on mass definition, as well as minor editorial improvements.iv ISO 2015 All rights reservedBS ISO 7992:2015ISO 7992:2015(E)IntroductionThis International Standard concerns one of a number of physical test methods that have been developed to me
19、asure various physical parameters 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 dif
20、ferent laboratories.The results of this test have to be considered in conjunction with other tests used to evaluate the 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
21、basis of a contract, or as part of a research project. ISO 2015 All rights reserved vBS ISO 7992:2015BS ISO 7992:2015Iron ores for blast furnace feedstocks Determination of reduction under loadCAUTION This International Standard may involve hazardous operations and equipment. This International Stan
22、dard 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 limitations prior to its use.1 ScopeThis Internati
23、onal Standard specifies a method to provide a relative measure for evaluating the structural stability of 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 and hot-bonded pellets.2 Norma
24、tive 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 applies. For undated references, the latest edition of the referenced document (including any amendments) a
25、pplies.ISO 2597-1, Iron ores Determination of total 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
26、proceduresISO 9035, Iron 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 isothermall
27、y reduced in a fixed bed, at 1 050 C, under static load, using a reducing gas consisting of CO, H2and N2, until a degree of reduction of 80 % is obtained. The differential gas pressure across the bed and the change in the test bed height are measured at 80 % reduction.5 Sampling, sample preparation
28、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 and lump ores shall be 12,5 mm + 10,0 mm.INTERNATIONAL STANDARD ISO 7992:2015(E) ISO 2015 All rights reserved 1BS ISO
29、7992:2015ISO 7992:2015(E)A test sample of at least 6,0 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
30、 between 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 tes
31、t portions.At least five test portions, each of approximately 1 200 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 recipien
32、t label.6 Apparatus6.1 GeneralThe test apparatus shall comprise the following:a) ordinary laboratory equipment, such as an oven, hand tools and safety equipment;b) a reduction-tube assembly;c) a furnace;d) a system to supply the gases and regulate the flow rates;e) a tumble drum;f) test sieves;g) a
33、weighing device.Figure 1 shows an example of the test apparatus.6.2 Reduction tube, with a double wall made of non-scaling, heat-resistant metal to withstand temperatures higher than 1 050 C and resistant to deformation. The internal diameter of the inner reduction tube shall be 125 mm 1 mm. A remov
34、able perforated plate, made of non-scaling, heat-resistant metal to withstand temperatures higher than 1 050 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 a diameter 1 mm less than the
35、internal 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. The internal diameter of the outer reduction tube shall be enough to allow gas flow preheating before entering the inner reduction tube.Figure 2 shows an example of a
36、reduction tube.Figure 3 shows the principle for oxygen flushing of thermocouples to avoid mismeasurement due to carbon deposition.6.3 Loading device, capable of supplying a total static load of 50 kPa 2 kPa evenly to the test portion. The load shall be transferred by means of a ram with rigid perfor
37、ated footplate, so as to distribute it evenly to the surface of the porcelain balls placed on top of the test portion. The footplate shall be 10 mm 2 ISO 2015 All rights reservedBS ISO 7992:2015ISO 7992:2015(E)thick, with a diameter 1 mm less than the internal diameter of the tube. The holes in the
38、plate shall be 3 mm to 4 mm in diameter, at a pitch centre distance of 5 mm to 6 mm.6.4 Device for measuring differential gas pressure, having a resolution of 0,01 kPa.6.5 Height-measuring device, having a resolution of 0,1 mm.6.6 Porcelain balls, having a size range between 10,0 mm and 12,5 mm.6.7
39、Furnace, having a heating capacity and temperature control able to maintain the entire test portion, as well as the gas entering the bed, at 1 050 C 10 C.6.8 Balance, capable of weighing the reduction tube assembly, including the test portion, to an accuracy of 1 g. The balance shall have an appropr
40、iate device to suspend the reduction tube assembly.6.9 Gas-supply system, capable of supplying the gases and regulating gas flow rates. A frictionless connection between the gas-supply system and the reduction tube shall be ensured to not affect the weight loss determination during reduction.6.10 We
41、ighing 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 (1,013 25 bar).7.2 Reducing gas7.2.1 Co
42、mpositionThe reducing gas shall consist of the following:CO 40,0 % 0,5 % (volume fraction);H22,0 % 0,5 % (volume fraction);N258,0 % 0,5 % (volume fraction).7.2.2 PurityImpurities in the reducing gas shall not exceed the following:CO20,2 % (volume fraction);O20,1 % (volume fraction);H2O 0,2 % (volume
43、 fraction).7.2.3 Flow rateThe flow rate of the reducing gas, during the entire reducing period, shall be maintained at 83 L/min 1 L/min. ISO 2015 All rights reserved 3BS ISO 7992:2015ISO 7992:2015(E)7.3 Heating and cooling gasNitrogen (N2) shall be used as the heating and cooling gas. Impurities sha
44、ll not exceed 0,1 % (volume fraction).The flow rate of N2shall be maintained at 50 L/min until the test portion reaches 1 050 C and at 83 L/min during temperature-equilibration period. If desired, the test portion may be cooled under nitrogen to below 100 C. During cooling, it shall be maintained at
45、 5 L/min.7.4 Temperature of the test portionThe temperature of the entire test portion shall be maintained at 1 050 C 10 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 test portionDuring the entire heating and
46、 reducing periods, the test portion shall be subjected to a constant load of 50 kPa 2 kPa applied over the surface of the bed.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
47、test portions 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 ReductionIn order to achieve a more uniform gas flow, place a double-layer bed of porcelain ba
48、lls (6.6) in the reduction tube (6.2) on the perforated plate and level its surface. Measure the height of the top surface of the porcelain layer.Take, at random, another test portion prepared in 5.2 and record its mass (m0). Place it on the bed of porcelain balls and level its surface.Place a furth
49、er double layer of the porcelain balls upon the test portion and level its surface. Measure the height of the top surface of this porcelain layer.Close the top of the reduction tube by connecting the heating assembly containing the loading device (6.3) to the reduction tube. Insert the reduction tube assembly into the furnace (6.7) and suspend it centrally from the balance (6.8), ensuring that there is no contact with the furnace wall or heating elements.Connect the thermocouple, ensuring that its
