1、BSI Standards Publication BS ISO 7992:2015 Iron ores for blast furnace feedstocks Determination of reduction under loadBS ISO 7992:2015 BRITISH STANDARD National foreword This British Standard is the UK implementation of ISO 7992:2015. It supersedes BS ISO 7992:2007 which is withdrawn. The UK partic
2、ipation 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 contract. Users are responsible for its
3、 correct application. The British Standards Institution 2015. Published by BSI Standards Limited 2015 ISBN 978 0 580 79291 5 ICS 73.060.10 Compliance with a British Standard cannot confer immunity from legal obligations. This British Standard was published under the authority of the Standards Policy
4、 and Strategy Committee on 31 August 2015. Amendments issued since publication Date Text affectedBS ISO 7992:2015 ISO 2015 Iron ores for blast furnace feedstocks Determination of reduction under load Minerais de fer pour charges de hauts fourneaux Dtermination de la rduction sous charge INTERNATIONA
5、L STANDARD ISO 7992 Third edition 2015-08-01 Reference number ISO 7992:2015(E)BS ISO 7992:2015ISO 7992:2015(E)ii ISO 2015 All rights reserved COPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in Switzerland All rights reserved. Unless otherwise specified, no part of this publication may be reproduced
6、 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 body in the country of the requester. ISO
7、 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 7992:2015ISO 7992:2015(E)Foreword iv Introduction v 1 Scope . 1 2 Normative references 1 3 T erms and definitions . 1 4 Principle 1 5 Sampli
8、ng, 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 . 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 c
9、ooling gas 4 7.4 Temperature of the test portion . 4 7.5 Loading of the test portion . 4 8 Procedure. 4 8.1 Number of determinations for the test 4 8.2 Chemical analysis 4 8.3 Reduction . 4 9 Expression of results 5 9.1 Preparation of the reduction curve . 5 9.2 Calculation of the differential press
10、ure at 80 % reduction (p80) . 5 9.3 Calculation of the change in the height of the test bed at 80 % reduction (h80) 6 9.4 Repeatability and acceptance of test results . 6 10 Test report . 6 11 V erification . 6 Annex A (normative) Flowsheet of the procedure for the acceptance of test results .11 Ann
11、ex B (informative) Derivation of equation for reducibility .12 ISO 2015 All rights reserved iii Contents PageBS ISO 7992:2015ISO 7992:2015(E) Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of prep
12、aring 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 right to be represented on that committee. International organizations, governmental and non-governmental, in
13、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 used to develop this document and those intended for its further maintenance are described in the ISO/IEC
14、 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 rules of the ISO/IEC Directives, Part 2 (see www.iso.org/directives). Attention is drawn to the possibility t
15、hat 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 identified during the development of the document will be in the Introduction and/or on the ISO list of patent
16、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 the meaning of ISO specific terms and expressions related to conformity assessment, as well as informa
17、tion about ISOs adherence to the WTO principles 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 third edition ca
18、ncels and replaces the second edition (ISO 7992:2007), of which it constitutes a minor 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) Introduction This International Stand
19、ard 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, crushing strength, apparent density, etc. This method was developed to provide a uniform procedure
20、, 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 the quality of iron ores as feedstocks for blast furnace processes. This International Standard can
21、 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 7992:2015BS ISO 7992:2015Iron ores for blast furnace feedstocks Determination of reduction under load CAUTION This Interna
22、tional Standard 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 deter
23、mine the applicability of regulatory limitations prior to its use. 1 Scope This International 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 furn
24、ace. This International Standard is applicable to lump ores 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 applies. For un
25、dated 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: Titrimetric meth
26、ods 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 T erms a nd definiti ons For the purposes of this d
27、ocument, the terms and definitions given in ISO 11323 apply. 4 Principle The test portion is isothermally reduced in a fixed bed, at 1 050 C, under static load, using a reducing gas consisting of CO, H 2and N 2 , until a degree of reduction of 80 % is obtained. The differential gas pressure across t
28、he bed and the change in the test bed height are measured at 80 % reduction. 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 and lum
29、p ores shall be 12,5 mm + 10,0 mm. INTERNATIONAL ST ANDARD ISO 7992:2015(E) ISO 2015 All rights reserved 1BS ISO 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
30、room temperature 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
31、 at random. 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 1 200 g ( the mass of one particle) shall be prepared from the test sample: four test portions for testing and one for
32、 chemical analysis. 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) a reductio
33、n-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 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 temperatu
34、res higher than 1 050 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 higher than 1 050 C, shall be mounted in the reduction tube to support the
35、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 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 oute
36、r reduction tube shall be enough to allow gas flow preheating before entering the inner reduction tube. Figure 2 shows an example of a 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 su
37、pplying 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 perforated 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
38、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 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,
39、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 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
40、 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. 6.9 Gas-supply system, capable of supplying the gases and regulating gas flow rates. A frictionless conne
41、ction between the gas-supply system and the reduction tube shall be ensured to not affect the weight loss determination during reduction. 6.10 Weighing device, capable of weighing the test sample and test portions to an accuracy of 1 g. 7 Test conditions 7.1 General Volumes and flow rates of gases u
42、sed 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 gas 7.2.1 Composition The reducing gas shall consist of the following:CO 40,0 % 0,5 % (volume fraction);H 2 2,0 % 0,5 % (volume fraction);N 2 58,0 % 0,5 % (volume
43、 fraction). 7.2.2 Purity Impurities in the reducing gas shall not exceed the following: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 83 L/min 1 L/min
44、. ISO 2015 All rights reserved 3BS ISO 7992:2015ISO 7992:2015(E) 7.3 Heating and cooling gas Nitrogen (N 2 ) shall 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 50 L/min until the test portion reaches 1 050 C a
45、nd 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 5 L/min. 7.4 Temperature of the test portion The temperature of the entire test portion shall be maintained at 1 050 C 10 C duri
46、ng the entire reducing period and, as such, the reducing gas shall be preheated before entering the test portion. 7.5 Loading of the test portion During the entire heating and reducing periods, the test portion shall be subjected to a constant load of 50 kPa 2 kPa applied over the surface of the bed
47、. 8 Procedure 8.1 Number of determinations for the test Carry out the test as many times as required by the procedure in Annex A. 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 I
48、SO 9035 and the total iron content (w 2 ) in accordance with ISO 2597-1 or ISO 2597-2. 8.3 Reduction In order to achieve a more uniform gas flow, place a double-layer bed of porcelain balls (6.6) in the reduction tube (6.2) on the perforated plate and level its surface. Measure the height of the top
49、 surface of the porcelain layer. Take, at random, another test portion prepared in 5.2 and record its mass (m 0 ). Place it on the bed of porcelain balls and level its surface. Place a further 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 assem
