《BS-ISO-7215-2007.pdf》由会员分享，可在线阅读，更多相关《BS-ISO-7215-2007.pdf（20页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS ISO 7215:2007 Iron ores for blast furnace feedstocks Determination of the reducibility by the final degree of reduction index ICS 73.060.10 ? Licensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI
2、BS ISO 7215:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 December 2007 BSI 2007 ISBN 978 0 580 55254 0 National foreword This British Standard is the UK implementation of ISO 7215:2007. It supersedes BS ISO 7215:1995 which is withd
3、rawn. 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 contract. Users are
4、responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments Licensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontro
5、lled Copy, (c) BSI Reference number ISO 7215:2007(E) INTERNATIONAL STANDARD ISO 7215 Third edition 2007-10-15 Iron ores for blast furnace feedstocks Determination of the reducibility by the final degree of reduction index Minerais de fer pour charges de hauts fourneaux Dtermination de la rductibilit
6、 relative par le degr final de lindice de rduction BS ISO 7215:2007 Licensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI ii Licensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20
7、:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI iii Contents Page 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. 2 6 Apparatus 2 7 Test conditions . 3 8 Procedure 4 9 Expressio
8、n of results . 5 10 Test report . 6 11 Verification 6 Annex A (normative) Flowsheet of the procedure for the acceptance of test results 9 Annex B (informative) Derivation of the equation for final degree of reduction 10 BS ISO 7215:2007 Licensed Copy: London South Bank University, London South Bank
9、University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI iv 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 carried out through IS
10、O 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. ISO collaborates c
11、losely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization. International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2. The main task of technical committees is to prepare International Standards. D
12、raft International Standards adopted by the technical committees are circulated to the member bodies for voting. Publication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. Attention is drawn to the possibility that some of the elements of this do
13、cument may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 7215 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 3, Physical testing. This third edition cancels and replaces the sec
14、ond edition (ISO 7215:1995), which has been revised to homogenise with other physical test standards. BS ISO 7215:2007 Licensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI v Introduction This International Standard
15、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, va
16、lidated by collaborative testing, to facilitate comparisons of tests made in different laboratories. The results of this test should be considered in conjunction with other tests used to evaluate the quality of iron ores as feedstocks for blast furnace processes. This International Standard may be u
17、sed 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. BS ISO 7215:2007 Licensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI blank Lic
18、ensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 1 Iron ores for blast furnace feedstocks Determination of the reducibility by the final degree of reduction index CAUTION This International Standard may involve haz
19、ardous materials, operations and equipment. This 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 applicability of regulato
20、ry 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 blast furnace. This Inter
21、national Standard is applicable to lump ores, sinters and hot-bonded pellets. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the refe
22、renced document (including any amendments) applies. ISO 2597-1:2006, Iron ores Determination of total iron content Part 1: Titrimetric method after tin(II) chloride reduction ISO 3082:2000 1), Iron ores Sampling and sample preparation procedures ISO 9035:1989, Iron ores Determination of acid-soluble
23、 iron(II) content Titrimetric method ISO 9507:1990, Iron ores Determination of total iron content Titanium(III) chloride reduction methods ISO 11323:2002, Iron ore and direct reduced iron Vocabulary 3 Terms and definitions For the purposes of this document, the terms and definitions given in ISO 113
24、23 apply. 4 Principle The test portion is isothermally reduced in a fixed bed, at 900 C, using a reducing gas consisting of CO and N2, for 180 min. The degree of reduction is calculated from the oxygen mass loss after 180 min. 1) Under revision to incorporate ISO 10836, Iron ores Method of sampling
25、and sample preparation for physical testing. BS ISO 7215:2007 Licensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 2 5 Sampling, sample preparation and preparation of test portions 5.1 Sampling and sample preparatio
26、n 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 be 20,0 mm +18,0 mm. A test sample of at least 2,5 kg, on a dry basis, of the sized material shall be obtain
27、ed. 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 two subsequent measurements becomes less than 0,05 % of the initial mass of the test sample. 5.2 Prep
28、aration of test portions Collect 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. At least 5 test portions, each of approximately 500 g mass ( the mass of 1 particle) shall be p
29、repared from the test sample: 4 test portions for testing and 1 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 Apparatus 6.1 General The test apparatus shall comprise: a) ordinary laboratory equipment, such as an
30、 oven, hand tools, time-control device and safety equipment; b) a reduction-tube assembly; 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 weighing device.
31、 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. A removable perforated plate, made of non-scaling, heat-resistant metal
32、 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 than the tube internal diameter. The holes in the plate shall be 2 mm to 3
33、 mm in diameter at a pitch center distance of 4 mm to 5 mm. Figure 2 shows an example of a reduction tube. BS ISO 7215:2007 Licensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 3 6.3 Furnace, having a heating capaci
34、ty 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 balance shall have an appropriate device to suspend or suppo
35、rt 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 determination during reduction. 6.6 Weighing de
36、vice, capable of weighing the test portion to an accuracy of 1 g. 7 Test conditions 7.1 General Volumes and flow rates of gases 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
37、 shall consist of: CO 30,0 % 1,0 % (volume fraction) N2 70,0 % 1,0 % (volume fraction) 7.2.2 Purity Impurities in the reducing gas shall not exceed: H2 0,2 % (volume fraction) CO2 0,2 % (volume fraction) O2 0,1 % (volume fraction) H2O 0,2 % (volume fraction) 7.2.3 Flow rate The flow rate of the redu
38、cing gas, during the entire reducing period, shall be maintained at 15 L/min 0,5 L/min. 7.3 Heating and cooling gas Nitrogen (N2) shall be used as the heating and cooling gas. Impurities shall not exceed 0,1 % (volume fraction). The flow rate of N2 shall be maintained at 5 L/min until the test porti
39、on reaches 900 C, and at 15 L/min during the temperature-equilibration period. BS ISO 7215:2007 Licensed Copy: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 4 7.4 Temperature of the test portion The temperature of the entir
40、e 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 many times as required by the procedure in Annex A. 8.2 C
41、hemical 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 (w1) in accordance with ISO 9035 and the total iron content (w2) in accordance with ISO 2597-1 or ISO 9507. 8.3 Reduction Take, at random, one test portion prepar
42、ed in 5.2 and record its mass (m0). Place it in the reduction tube (6.2) and level its surface. Close the top of the reduction tube. Connect the thermocouple, ensuring that its tip is in the centre of the test portion. Insert the reduction tube into the furnace (6.3) and suspend or support it centra
43、lly 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 N2 through 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, incre
44、ase the flow rate to 15 L/min. While maintaining the flow of N2, continue heating until a constant mass of the test portion and a constant temperature of 900 C 10 C for 30 min are attained. DANGER Carbon monoxide and the reducing gas, which contains carbon monoxide, are toxic and therefore hazardous
45、. 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. Record the mass of the test portion (m1) and immediately introduce the reducing gas at a flow rate of 15 L/min 0,
46、5 L/min to replace the N2. At the end of 180 min of reduction, record the mass of the test portion (m2), turn off the power and stop the flow of the reducing gas. Introduce N2 at a flow rate of 5 L/min for 5 min or more to purge the reducing gas from the tube. NOTE 1 If reduction versus time curves
47、are required, record the mass of the test portion every 10 min during the first hour and every 15 min during the last 2 h. NOTE 2 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. BS ISO 7215:2007 Licensed Co
48、py: London South Bank University, London South Bank University, Thu Dec 20 03:20:39 GMT+00:00 2007, Uncontrolled Copy, (c) BSI 5 9 Expression of results 9.1 Calculation of the final degree of reduction (R180) The final degree of reduction R180, expressed as a percentage by mass, is calculated from t
49、he following equation 2): () 412 180 021 10 0,4300,111 mm R mww = (1) where m0 is the mass, in grams, of the test portion; m1 is the mass, in grams, of the test portion immediately before starting the reduction; m2 is the mass, in grams, of the test portion after 180 min of reduction; w1 is the iron(II) oxide content, as a percentage by mass, of the test portion prior to the test, determined in accordance with ISO 9035, calculated from