BS ISO 7215-2015 Iron ores for blast furnace feedstocks Determination of the reducibility by the final degree of reduction index《鼓风炉给料用铁矿石 用还原指数的最终值测定还原性能》.pdf

1、BSI Standards PublicationBS ISO 7215:2015Iron ores for blast furnacefeedstocks Determinationof the reducibility by the finaldegree of reduction indexBS ISO 7215:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 7215:2015. Itsupersedes BS ISO 7215:2007 which

2、is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee ISE/58, Iron ores.A list of organizations represented on this committee can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 necessaryprovisions of a contract. Users ar

3、e responsible for its correctapplication. The British Standards Institution 2015. Published by BSI StandardsLimited 2015ISBN 978 0 580 79290 8ICS 73.060.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theSta

4、ndards Policy and Strategy Committee on 30 September 2015.Amendments issued since publicationDate Text affectedBS ISO 7215:2015 ISO 2015Iron ores for blast furnace feedstocks Determination of the reducibility by the final degree of reduction indexMinerais de fer pour charges de hauts fourneaux Dterm

5、ination de la rductibilit relative par le degr final de lindice de rductionINTERNATIONAL STANDARDISO7215Fourth edition2015-08-15Reference numberISO 7215:2015(E)BS ISO 7215:2015ISO 7215:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights res

6、erved. 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 posting on the internet or an intranet, without prior written permission. Permission can be requested from either I

7、SO 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 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 7215:2015ISO 7215:2015(E)Foreword ivIntroduction v1 Scope . 12 Norm

8、ative references 13 Terms and definitions . 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

9、 . 37.2.2 Purity . 37.2.3 Flow rate . 37.3 Heating and cooling gas 37.4 Temperature of the test portion . 38 Procedure. 38.1 Number of determinations for the test 38.2 Chemical analysis 48.3 Reduction . 49 Expression of results 59.1 Calculation of the degree of reduction (R180) 59.2 Repeatability fo

10、r R180and acceptance of test results . 510 Test report . 511 Verification . 6Annex A (normative) Flowsheet of the procedure for the acceptance of test results 9Annex B (informative) Derivation of the formula for final degree of reduction .10 ISO 2015 All rights reserved iiiContents PageBS ISO 7215:2

11、015ISO 7215:2015(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 sub

12、ject 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 Commission (I

13、EC) 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 documents should be

14、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 responsible for identifyi

15、ng 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 for the convenience

16、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 URL: Foreword - Suppl

17、ementary informationThe committee responsible for this document is ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 3, Physical testing.This fourth edition cancels and replaces the third edition (ISO 7215:2007), of which it constitutes a minor revision to contemplate the outcome of the

18、studies on mass definition, as well as minor editorial improvements.iv ISO 2015 All rights reservedBS ISO 7215:2015ISO 7215:2015(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

19、 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 results of this test have

20、 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 basis of a contract, or as part of a research pro

21、ject. ISO 2015 All rights reserved vBS ISO 7215:2015BS ISO 7215:2015Iron ores for blast furnace feedstocks Determination of the reducibility by the final degree of reduction indexCAUTION This International Standard may involve hazardous operations and equipment. This International Standard does not

22、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 International Standard

23、specifies a method to provide a relative measure for evaluating the extent to 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 ore, sinters, and hot-bonded p

24、ellets.2 Normative 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

25、 amendments) applies.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 sampl

26、e preparation 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

27、is isothermally reduced in a fixed bed, at 900 C, using a reducing gas consisting of CO and N2, for 180 min. The final degree of reduction is calculated from the oxygen mass loss after 180 min (R180).5 Sampling, sample preparation, and preparation of test portions5.1 Sampling and sample preparationS

28、ampling of a lot and preparation of a test sample shall be in accordance with ISO 3082.The size range for pellets shall be - 12,5 mm + 10,0 mm.The size range for sinters and lump ores shall be - 20,0 mm + 18,0 mm.INTERNATIONAL STANDARD ISO 7215:2015(E) ISO 2015 All rights reserved 1BS ISO 7215:2015I

29、SO 7215:2015(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 t

30、wo 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 portions

31、.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.6 Appar

32、atus6.1 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 test;d)

33、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 900 C and resistant to deformation.The internal diameter shall be 75 mm 1 mm.

34、A removable perforated plate, made of non-scaling, heat-resistant metal to withstand temperatures higher than 900 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 less tha

35、n 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.6.3 Furnace, having a heating capacity and temperature control able to maintain the entire test portion, as well as t

36、he gas entering the bed, at 900 C 10 C.6.4 Balance, capable of weighing the reduction tube assembly, including the test portion, to an accuracy of 0,5 g. The balance shall have an appropriate device to suspend the reduction tube assembly.6.5 Gas-supply system, capable of supplying the gases and regu

37、lating 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.2 ISO 2015 All rights reservedBS ISO 7215:2015ISO 7215:2015(E)6.6 Weighing device, capable of weighing the tes

38、t sample and the 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 consis

39、t of the following:CO 30,0 % 1,0 % (volume fraction)N270,0 % 1,0 % (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 red

40、ucing gas, during the entire reducing period, shall be maintained at 15 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 5 L/min until the test portion

41、reaches 900 C and at 15 L/min during 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 900 C 10 C during the entire reducing period and, as such, the reducing gas sh

42、all 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. ISO 2015 All rights reserved 3BS ISO 7215:2015ISO 7215:2015(E)8.2 Chemical analysisTake, at random, one of the test portions

43、 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 re

44、duction 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 t

45、hat 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 N2thr

46、ough the test portion at a rate of at least 5 L/min and commence heating. When the temperature of the test portion approaches 900 C, increase the flow rate to 15 L/min. Continue heating while maintaining the flow of N2, until the balance reading is constant and the temperature is constant at 900 C 1

47、0 C for 30 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 ea

48、ch country.Tare the balance, start the time control device and immediately introduce the reducing gas at a flow rate of 15 L/min 0,5 L/min to replace the N2. After 180 min of reduction, record the mass loss of the test portion (m), turn off the power and stop the flow of the reducing gas. Introduce

49、N2at a flow rate of 5 L/min for 5 min or more to purge the reducing gas from the tube.NOTE If a reduction versus time curve is required, record the mass loss of the test portion continuously or every 10 min during the first hour and every 15 min during the last 2 h.In the case of lump ores, the temperature of the test portion should be raised to 900 C over more than 60 min, to reduce their decrepitation.4 ISO 2015 All rights reservedBS ISO 7215:2015ISO 7215:2015(E)9 Expression of results9.1