1、BS ISO 16878:2016Iron ores Determination ofmetallic iron content Iron(III)chloride titrimetric methodBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 16878:2016 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 16878:2016.It
2、 supersedes DD ISO/TS 16878:2010 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee ISE/58, Iron ores.A list of organizations represented on this committee can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 nece
3、ssaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2016.Published by BSI Standards Limited 2016ISBN 978 0 580 91141 5ICS 73.060.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was
4、published under the authority of theStandards Policy and Strategy Committee on 31 July 2016.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 16878:2016 ISO 2016Iron ores Determination of metallic iron content Iron(III) chloride titrimetric methodMinerais de fer Dosage
5、 du fer mtallique Mthode titrimtrique au chlorure de fer(III)INTERNATIONAL STANDARDISO16878First edition2016-07-01Reference numberISO 16878:2016(E)BS ISO 16878:2016ISO 16878:2016(E)ii ISO 2016 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2016, Published in SwitzerlandAll rights reserved. Unle
6、ss 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 ISO at the a
7、ddress 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 16878:2016ISO 16878:2016(E)Foreword iv1 Scope . 12 Normative references 13 Ter
8、ms and definitions . 14 Principle 15 Reagents 16 Apparatus . 27 Sampling and sample preparation 38 Procedure. 38.1 Number of determinations . 38.2 Preparation of test portions 38.3 Determination . 39 Expression of results 49.1 Calculation of the metallic iron content 49.2 General treatment of result
9、 49.2.1 Repeatability and permissible tolerances 49.2.2 Determination of analytical result 49.2.3 Between-laboratories precision . 49.2.4 Check for trueness 59.2.5 Calculation of final result 610 Test report . 6Annex A (normative) Flowsheet of the procedure for the acceptance of test results 7Annex
10、B (informative) Derivation of precision statements 8Bibliography 9 ISO 2016 All rights reserved iiiContents PageBS ISO 16878:2016ISO 16878:2016(E)ForewordISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of p
11、reparing 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,
12、in 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/I
13、EC 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
14、that 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
15、 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 informat
16、ion about ISOs adherence to the World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT) see the following URL: www.iso.org/iso/foreword.html.The committee responsible for this document is ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 2, Chemical analysis.Th
17、is first edition of ISO 16878 cancels and replaces ISO/TS 16878:2010, which has been technically revised.iv ISO 2016 All rights reservedBS ISO 16878:2016INTERNATIONAL STANDARD ISO 16878:2016(E)Iron ores Determination of metallic iron content Iron(III) chloride titrimetric methodCAUTION This Internat
18、ional 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 determ
19、ine the applicability of regulatory limitations prior to its use.1 ScopeThis International Standard specifies a titrimetric method for the determination of the metallic iron content of reduced iron ores.This method is applicable to a concentration range of 57,5 % mass fraction to 90,5 % mass fractio
20、n of the metallic iron.NOTE The term “metallic iron” means those forms of iron not bonded to oxygen or not present as pyrite.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
21、, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies.ISO 385, Laboratory glassware BurettesISO 1042, Laboratory glassware One-mark volumetric flasksISO 10835, Direct reduced iron and hot briquetted iron Sampling an
22、d sample preparationISO 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 PrincipleIron present in the oxidation state Fe0in the sample is oxidized to Fe+2by the action of FeCl3according to
23、 the following reaction:Fe Fe Fe03 223+The Fe+2is titrated with potassium dichromate solution using the sodium diphenylaminesulfonate indicator.5 ReagentsDuring the analysis, use only reagents of recognized analytical reagent grade and only distilled water or water of equivalent purity. ISO 2016 All
24、 rights reserved 1BS ISO 16878:2016ISO 16878:2016(E)5.1 Iron(III) chloride solution.Add 250 g of iron(III) chloride hexahydrate to a 2 000 ml container holding 600 ml of water and agitate until it is completely dissolved. Dilute with water to a volume of 1 l.NOTE For better dissolution of the FeCl3,
25、 it is recommended to use a warm water bath. The ideal condition is a complete dissolution of the salt resulting in a translucent solution.5.2 Sulfuric acid, 1,84 g/ml.5.3 Phosphoric acid, 1,7 g/ml.5.4 Solution 15 % sulfuric acid/15 % phosphoric acid mixture.Add 1 000 ml of water to a 3 000 ml beake
26、r. Place the beaker in a cool place and add slowly with stirring 300 ml of phosphoric acid (5.3). Allow cooling. Add slowly with stirring 300 ml of sulfuric acid (5.2) and allow cooling. Dilute this mixture to 2 000 ml with stirring. Store the solution in a 2 000 ml high-density polyethylene bottle
27、or equivalent container.5.5 Sodium diphenylaminesulfonate.Dissolve 0,2 g of powdered sodium diphenylaminesulfonate (C6H5NHC6H4SO3Na) in a small volume of water and dilute to 100 ml.Store this solution in a brown glass bottle.5.6 Standard potassium dichromate solution, 0,016 67 mol/l.Dry potassium di
28、chromate at 150 C for 3 h. Remove potassium dichromate from the oven and cool to room temperature in a desiccator or over silica gel. For a minimum purity 99,9 % (mass fraction) potassium dichromate weigh 9,808 g into a weighing scoop and transfer qualitatively to a 2 000 ml volumetric flask. Add 1
29、500 ml of water and dissolve potassium dichromate. When dissolution is complete, make up to volume and mix thoroughly.5.7 Inert gas, carbon dioxide (CO2), argon (Ar) or nitrogen (N2).6 ApparatusOne mark A-grade volumetric flasks complying with the specifications of ISO 1042 and the following.6.1 Ana
30、lytical balance, capable of weighing to the nearest 0,1 mg.6.2 Erlenmeyer flask, widemouth (500 ml).6.3 Stopper, to fit Erlenmeyer flask, modified to allow the inert gas to pass through the beaker.6.4 Magnet stirrer, with magnetic stirring bar.6.5 Measuring cylinder, of appropriate volume.6.6 A grad
31、e burette, mark A, complying with the specifications of ISO 385.6.7 Non-magnetic spatula.2 ISO 2016 All rights reservedBS ISO 16878:2016ISO 16878:2016(E)7 Sampling and sample preparationFor analysis, use a laboratory sample of 160 m particle size which has been taken and prepared in accordance with
32、ISO 10835. Metallized fines should be dried in an inert atmosphere and stored, where possible, in an airtight container flushed with a dry inert gas to prevent re-oxidation of the sample.Thoroughly mix the laboratory sample using non-magnetic materials. Taking multiple increments with a non-magnetic
33、 spatula, extract a test sample of not less than 25 g in such a manner that it is representative of the whole of the contents of the container. When taking the test portion for the purpose of analysis, expose the sample to air for as short a time as practical. After weighing, immediately replace the
34、 remaining material in its container, flush with an inert gas and store.8 Procedure8.1 Number of determinationsAll determinations should be carried out in duplicate. If necessary, make further determinations in accordance with the flowsheet presented in Annex A.8.2 Preparation of test portionsAccura
35、tely weigh 0,200 0 g 0,005 0 g of the test sample. Record the sample mass (m).8.3 DeterminationTransfer the sample to a 500 ml Erlenmeyer flask and fit the stopper to the flask. Eliminate air from the flask by flushing with a controlled flow of inert gas (approximately 3 l/min) for 5 min. Remove the
36、 stopper and dispense 35 ml of iron(III) chloride solution (5.1) into the flask. Add sufficient water to the sample to cover the stirring bar (at least 15 ml). Adjust the inert gas flow to a gentle stream (approximately 5 l/min) and fit the stopper to the flask.WARNING Adjust the inert gas flow whil
37、e the stopper is not fitted to the flask. Adjusting the inert gas flow while the stopper is fitted to the beaker can cause the solution to be forced out of the beaker.Stir the solution with a magnetic agitator for at least 45 min maintaining the inert gas flow.Remove the stopper and add 50 ml of sul
38、furic acid-phosphoric acid solution (5.4), 200 ml of water and 1 ml of sodium diphenylamine sulfonate indication (5.5).Titrate the solution with potassium dichromate (5.6). The end point is reached when a final drop of the titrant imparts a permanent purple colour.In each run, one blank test shall b
39、e carried out in parallel with the analysis of the ore sample(s) under the same conditions.Perform a blank test by following the procedure without the sample. Record the blank titration volume as V0.For every new batch of iron (III) chloride solution, a blank should be performed. ISO 2016 All rights
40、 reserved 3BS ISO 16878:2016ISO 16878:2016(E)9 Expression of results9.1 Calculation of the metallic iron contentDetermine the metallic iron content in the sample, Fe(met), as a percentage by mass, using Formula (1):%Fem/m(met)=()VVm00 005 584 73100,(1)whereV is the volume of potassium dichromate con
41、sumed during the titration of the sample, in millilitres;V0is the volume of potassium dichromate consumed during the titration of the blank, in mil-lilitres;m is the sample mass, in grams;3 is the constant of stoichiometric relation according to the reaction quoted in Clause 4;0,005 584 7 is the mul
42、tiple of atomic mass of iron.9.2 General treatment of result9.2.1 Repeatability and permissible tolerancesThe precision of this analytical method is expressed by the following values: Rd= 0,349; P = 1,015; Sd= 0,123; SL= 0,344.whereRdis the independent duplicate limit;P is the permissible tolerance
43、between laboratories;Sdis the independent duplicate standard deviation;SLis the between-laboratories standard deviation.NOTE Additional information is given in Annex B.9.2.2 Determination of analytical resultHaving computed the independent duplicate results according to Formula (1), compare them wit
44、h the independent duplicate limit (Rd), using the procedure given in Annex A.9.2.3 Between-laboratories precisionBetween-laboratories precision is used to determine the agreement between the final results reported by two laboratories. The assumption is that both laboratories followed the same proced
45、ure described in 8.3.4 ISO 2016 All rights reservedBS ISO 16878:2016ISO 16878:2016(E)Compute the following quantity:12122=+(2)where1is the final result reported by laboratory 1;2is the final result reported by laboratory 2;12is the mean of final results.If 12P , the final results are in agreement.9.
46、2.4 Check for truenessThe trueness of the analytical method shall be checked by applying it to a certified reference material (CRM) or a reference material (RM). The procedure is the same as that described above. After confirmation of the precision, the final laboratory result is compared with the r
47、eference or certified value, Ac. There are two possibilities:a) cc,AC in which case, the difference between the reported result and the reference/certified value is statistically insignificant.b) cc,AC in which case, the difference between the reported result and the reference/certified value is sta
48、tistically significant.wherecis the final result for the certified reference material;Acis the reference/certified value for the CRM/RM;C is a value dependent on the type of CRM/RM used.Certified reference materials used for this purpose should be prepared and certified in accordance with ISO Guide
49、35.C shall be calculated as given in Formula (3):CSNn=+222C2CLd(3)whereSCis the standard deviation of laboratory means (each data for calculating the standard deviation is the average data in each certifying laboratory) of the CRM/RM;NCis the number of certifying laboratories;n is the number of replicate determinations carried out on the CRM/RM. ISO 2016 All rights reserved 5BS ISO 16878:2016ISO 16878:2016(E)For CRMs certified by only one laboratory, C shall be calculated as given in Formu
