1、BSI Standards Publication BS ISO 7215:2015 Iron ores for blast furnace feedstocks Determination of the reducibility by the final degree of reduction indexBS ISO 7215:2015 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO 7215:2015. It supersedes BS ISO 7215:200
2、7 which is withdrawn. The UK participation in its preparation was entrusted to Technical Committee ISE/58, Iron ores. A list of organizations represented on this committee can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a cont
3、ract. Users are responsible for its correct application. The British Standards Institution 2015. Published by BSI Standards Limited 2015 ISBN 978 0 580 79290 8 ICS 73.060.10 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under th
4、e authority of the Standards Policy and Strategy Committee on 30 September 2015. Amendments issued since publication Date Text affectedBS ISO 7215:2015 ISO 2015 Iron ores for blast furnace feedstocks Determination of the reducibility by the final degree of reduction index Minerais de fer pour charge
5、s de hauts fourneaux Dtermination de la rductibilit relative par le degr final de lindice de rduction INTERNATIONAL STANDARD ISO 7215 Fourth edition 2015-08-15 Reference number ISO 7215:2015(E)BS ISO 7215:2015ISO 7215:2015(E)ii ISO 2015 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2015, Publ
6、ished in Switzerland All 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 posting on the internet or an intranet, without prior written permission. Permis
7、sion can be requested from either ISO at the address below or ISOs member body in the country of the requester. ISO copyright office Ch. de Blandonnet 8 CP 401 CH-1214 Vernier, Geneva, Switzerland Tel. +41 22 749 01 11 Fax +41 22 749 09 47 copyrightiso.org www.iso.orgBS ISO 7215:2015ISO 7215:2015(E)
8、Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 Terms and definitions . 1 4 Principle 1 5 Sampling, sample preparation, and preparation of test portions 1 5.1 Sampling and sample preparation . 1 5.2 Preparation of test portions 2 6 Apparatus . 2 6.1 General . 2 7 Test conditions .
9、3 7.1 General . 3 7.2 Reducing gas . 3 7.2.1 Composition . 3 7.2.2 Purity . 3 7.2.3 Flow rate . 3 7.3 Heating and cooling gas 3 7.4 Temperature of the test portion . 3 8 Procedure. 3 8.1 Number of determinations for the test 3 8.2 Chemical analysis 4 8.3 Reduction . 4 9 Expression of results 5 9.1 C
10、alculation of the degree of reduction (R 180 ) 5 9.2 Repeatability for R 180and acceptance of test results . 5 10 Test report . 5 11 Verification . 6 Annex A (normative) Flowsheet of the procedure for the acceptance of test results 9 Annex B (informative) Derivation of the formula for final degree o
11、f reduction .10 ISO 2015 All rights reserved iii Contents PageBS ISO 7215:2015ISO 7215:2015(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carri
12、ed out through ISO technical committees. 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. I
13、SO collaborates closely with the 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 differen
14、t approval criteria needed for the 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 b
15、e the subject of patent rights. 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)
16、. 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 the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles
17、 in the Technical Barriers to Trade (TBT) see the following URL: Foreword - Supplementary information The 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
18、:2007), of which it constitutes a minor revision to contemplate the outcome of the studies on mass definition, as well as minor editorial improvements.iv ISO 2015 All rights reservedBS ISO 7215:2015ISO 7215:2015(E) Introduction This International Standard concerns one of a number of physical test me
19、thods that have been developed to measure 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 facilit
20、ate comparisons of tests made in different 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 pr
21、oduction quality control system, as a basis of a contract, or as part of a research project. 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 index CAUTION This International Standa
22、rd may involve hazardous operations 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 appl
23、icability of regulatory limitations prior to its use. 1 Scope This International Standard 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 blas
24、t furnace. This International Standard is applicable to lump ore, sinters, and hot-bonded pellets. 2 Normative references The 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
25、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 reduction ISO 2597-2, Iron ores Determination of total iron content Part 2: T
26、itrimetric methods after titanium(III) chloride reduction ISO 3082, Iron ores Sampling and sample preparation procedures ISO 9035, Iron ores Determination of acid-soluble iron(II) content Titrimetric method ISO 11323, Iron ore and direct reduced iron Vocabulary 3 Terms and definitions For the purpos
27、es of this document, the terms and definitions given in ISO 11323 apply. 4 Principle The test portion is isothermally reduced in a fixed bed, at 900 C, using a reducing gas consisting of CO and N 2 , for 180 min. The final degree of reduction is calculated from the oxygen mass loss after 180 min (R
28、180 ). 5 Sampling, sample preparation, and preparation of test portions 5.1 Sampling and sample preparation Sampling 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
29、 be - 20,0 mm + 18,0 mm. INTERNATIONAL ST ANDARD ISO 7215:2015(E) ISO 2015 All rights reserved 1BS ISO 7215:2015ISO 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 tempe
30、rature before preparation of the test portions. 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 portions Collect each test portion by taking ore particles at random
31、. NOTE Manual methods of division recommended in ISO 3082, such as riffling, can be applied to obtain the test portions. 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 analy
32、sis. Weigh the test portions to the nearest 1 g and register the mass of each test portion on its recipient label. 6 Apparatus 6.1 General The test apparatus shall comprise the following: a) ordinary laboratory equipment, such as an oven, hand tools, and safety equipment; b) reduction-tube assembly;
33、 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) 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-r
34、esistant metal to withstand temperatures higher than 900 C and resistant to deformation. The internal diameter shall be 75 mm 1 mm. 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
35、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 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
36、a reduction tube. 6.3 Furnace, having a heating capacity and temperature control able to maintain the entire test portion, as well as the 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 balanc
37、e shall have an appropriate device to suspend the reduction tube assembly. 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 dete
38、rmination during reduction.2 ISO 2015 All rights reservedBS ISO 7215:2015ISO 7215:2015(E) 6.6 Weighing device, capable of weighing the test sample and the test portions to an accuracy of 1 g. 7 Test conditions 7.1 General Volumes and flow rates of gases used are as measured at a reference temperatur
39、e of 0 C and at a reference atmospheric pressure of 101,325 kPa (1,013 25 bar). 7.2 Reducing gas 7.2.1 Composition The reducing gas shall consist of the following: CO 30,0 % 1,0 % (volume fraction) N 2 70,0 % 1,0 % (volume fraction) 7.2.2 Purity Impurities in the reducing gas shall not exceed the fo
40、llowing: H 2 0,2 % (volume fraction) CO 2 0,2 % (volume fraction) O 2 0,1 % (volume fraction) H 2 O 0,2 % (volume fraction) 7.2.3 Flow rate The flow rate of the reducing gas, during the entire reducing period, shall be maintained at 15 L/min 0,5 L/min. 7.3 Heating and cooling gas Nitrogen (N 2 ) sha
41、ll be used as the heating and cooling gas. Impurities shall not exceed 0,1 % (volume fraction). The flow rate of N 2shall be maintained at 5 L/min until the test portion reaches 900 C and at 15 L/min during temperature-equilibration period. During cooling, it shall be maintained at 5 L/min. 7.4 Temp
42、erature of the test portion The 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 shall be preheated before entering the test portion. 8 Procedure 8.1 Number of determinations for the test Carry out the test as m
43、any times as required by the procedure in Annex A. ISO 2015 All rights reserved 3BS ISO 7215:2015ISO 7215:2015(E) 8.2 Chemical analysis Take, at random, one of the test portions prepared in 5.2 and use it for the determination of the iron(II) oxide content (w 1 ) in accordance with ISO 9035 and the
44、total iron content (w 2 ) in accordance with ISO 2597-1 or ISO 2597-2. 8.3 Reduction Take, at random, another test portion prepared in 5.2 and record its mass (m 0 ). Place it in the reduction tube (6.2) and level its surface. NOTE In order to achieve a more uniform gas flow, a double-layer bed of p
45、orcelain 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 that its tip is in the centre of the test portion, as shown in Figure 1. Insert the reduction tube into the furnac
46、e (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 N 2through the test portion at a rate of at least 5 L/min and commence heating. When the temperature of the test po
47、rtion approaches 900 C, increase the flow rate to 15 L/min. Continue heating while maintaining the flow of N 2 , until the balance reading is constant and the temperature is constant at 900 C 10 C for 30 min. DANGER Carbon monoxide and the reducing gas, which contains carbon monoxide, are toxic and
48、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 country. Tare the balance, start the time control device and immediately introduce the reducing gas at
49、a flow rate of 15 L/min 0,5 L/min to replace the N 2 . 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 N 2at 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
