1、BS ISO 13312:2017Iron ores Determination ofpotassium Flame atomicabsorption spectrometricmethodBSI Standards PublicationWB11885_BSI_StandardCovs_2013_AW.indd 1 15/05/2013 15:06BS ISO 13312:2017 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 13312:2017. It supe
2、rsedes BS ISO 13312:2006 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee ISE/58, Iron ores.A list of organizations represented on this committee can be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
3、provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2017.Published by BSI Standards Limited 2017ISBN 978 0 580 93912 9 ICS 73.060.10 Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was p
4、ublished under the authority of the Standards Policy and Strategy Committee on 31 March 2017.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 13312:2017 ISO 2017Iron ores Determination of potassium Flame atomic absorption spectrometric methodMinerais de fer Dosage du
5、potassium Mthode par spectromtrie dabsorption atomique dans la flammeINTERNATIONAL STANDARDISO13312Third edition2017-03Reference numberISO 13312:2017(E)BS ISO 13312:2017ISO 13312:2017(E)ii ISO 2017 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2017, Published in SwitzerlandAll rights reserved.
6、 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 ISO at
7、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 13312:2017ISO 13312:2017(E)Foreword iv1 Scope . 12 Normative references 1
8、3 Terms and definitions . 14 Principle 15 Reagents 26 Apparatus . 27 Sampling and samples 47.1 Laboratory sample . 47.2 Preparation of predried test samples 48 Procedure. 48.1 Number of determinations . 48.2 Test portion 48.3 Blank test and check test 48.4 Determination . 58.4.1 General 58.4.2 Decom
9、position of the test portion 58.4.3 Treatment of the solution. 58.4.4 Preparation of the set of calibration solutions 58.4.5 Adjustment of atomic absorption spectrometer 68.4.6 Atomic absorption measurements . 69 Expression of results 69.1 Calculation of mass fraction of potassium 69.2 General treat
10、ment of results . 79.2.1 Repeatability and permissible tolerance 79.2.2 Determination of analytical result 79.2.3 Between-laboratories precision . 79.2.4 Check for trueness 89.2.5 Calculation of final result 99.3 Oxide factor 910 Test report . 9Annex A (normative) Flowsheet of the procedure for the
11、acceptance of analytical values for test samples 10Annex B (informative) Derivation of repeatability and permissible tolerance formulae 11Annex C (informative) Precision data obtained by international analytical trials .12Bibliography .13 ISO 2017 All rights reserved iiiContents PageBS ISO 13312:201
12、7ISO 13312:2017(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 subj
13、ect 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 (IE
14、C) 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
15、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 identi
16、fying 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 conven
17、ience of users and does not constitute an endorsement. For an explanation on the voluntary nature of standards, the meaning of ISO specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the World Trade Organization (WTO) principles in the Tech
18、nical Barriers to Trade (TBT) see the following URL: www .iso .org/ iso/ foreword .html.This document was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 2, Chemical analysis.This third edition cancels and replaces the second edition (ISO 13312:2006), of
19、 which it constitutes a minor revision with the following changes: in 7.2, a new sentence to make reference to ISO 2596 has been included; in 9.2.4, Formula (7) and the relevant descriptions have been modified to harmonize this subclause across all International Standards for which ISO/TC 102/SC 2 i
20、s responsible; in 5.4, 5.5, 8.4.2 and 9.2.1, the footnotes have been moved to the appropriate place.iv ISO 2017 All rights reservedBS ISO 13312:2017INTERNATIONAL STANDARD ISO 13312:2017(E)Iron ores Determination of potassium Flame atomic absorption spectrometric methodWARNING This document may invol
21、ve hazardous materials, operations and equipment. This document does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this document to establish appropriate health and safety practices and determine the applicability of regulatory lim
22、itations prior to use.1 ScopeThis document specifies a flame atomic absorption spectrometric method for the determination of the mass fraction of potassium in iron ores.This method is applicable to mass fractions of potassium between 0,002 5 % and 0,52 % in natural iron ores, iron ore concentrates a
23、nd agglomerates, including sinter products.2 Normative referencesThe following documents are referred to in the text in such a way that some or all of their content constitutes requirements of this document. For dated references, only the edition cited applies. For undated references, the latest edi
24、tion of the referenced document (including any amendments) applies.ISO 648, Laboratory glassware Single-volume pipettesISO 1042, Laboratory glassware One-mark volumetric flasksISO 2596, Iron ores Determination of hygroscopic moisture in analytical samples Gravimetric, Karl Fischer and mass-loss meth
25、odsISO 3082, Iron ores Sampling and sample preparation proceduresISO 3696, Water for analytical laboratory use Specification and test methodsISO 7764, Iron ores Preparation of predried test samples for chemical analysisISO 11323, Iron ore and direct reduced iron Vocabulary3 Terms and definitionsFor
26、the purposes of this document, the terms and definitions given in ISO 11323 apply.ISO and IEC maintain terminological databases for use in standardization at the following addresses: IEC Electropedia: available at h t t p :/ www .electropedia .org/ ISO Online browsing platform: available at h t t p
27、:/ www .iso .org/ obp4 PrincipleThe test portion is decomposed by treatment with hydrochloric acid and hydrofluoric acid, followed by evaporation to dryness. The residue is wetted and the evaporation is repeated with a new portion of hydrochloric acid. The residue is dissolved with hydrochloric acid
28、 followed by appropriate dilution. The solution is aspirated into the air/acetylene flame of the atomic absorption apparatus. ISO 2017 All rights reserved 1BS ISO 13312:2017ISO 13312:2017(E)The absorbance value obtained for potassium is measured in comparison with those obtained from calibration sol
29、utions.5 ReagentsDuring the analysis, use only reagents of recognized analytical grade and only water that complies with Grade 2 of ISO 3696.Reagents are to be selected or purified for the lowest possible blank value.5.1 Hydrochloric acid, 1,16 g/ml to 1,19 g/ml.5.2 Hydrofluoric acid, 1,13 g/ml, 40
30、% (mass fraction), or 1,19 g/ml, 48 % (mass fraction).5.3 Hydrochloric acid, 1,16 g/ml to 1,19 g/ml, diluted 1 + 2.5.4 Background solution.Dissolve 43 g of high-purity iron oxide powder in 500 ml of hydrochloric acid (5.1). Allow to cool and dilute with water to 1 000 ml.Instead of iron oxide, the u
31、se of metallic iron with a suitable oxidant is permitted. The alkali content of the oxidant shall be low.5.5 Potassium, standard solution, 20 g K/ml.Pulverize about 3 g of high-purity potassium chloride in an agate mortar, dry in an oven at 105 C to 110 C for 2 h, and allow to cool to room temperatu
32、re in a desiccator. Dissolve 1,907 g in water, dilute with water to 1 000 ml in a volumetric flask and mix.Transfer 10,0 ml of this solution to a 500 ml volumetric flask, dilute with water to volume and mix.NOTE Glass equipment can be used.Store this standard solution in a plastic bottle.1 ml of thi
33、s standard solution contains 20 g of potassium.6 ApparatusOrdinary laboratory equipment, including one-mark pipettes and one-mark volumetric flasks complying with the specifications of ISO 648 and ISO 1042, respectively, and the following.6.1 Polytetrafluoroethylene (PTFE) beakers, of capacity 100 m
34、l, provided with PTFE covers.6.2 PTFE-coated magnetic stirring bars.6.3 PTFE digestion bomb.6.4 Plastic pipettes.6.5 Plastic volumetric flasks and storage bottles.6.6 Magnetic stirring hotplates.NOTE Platinum vessels can be used instead of PTFE beakers.2 ISO 2017 All rights reservedBS ISO 13312:2017
35、ISO 13312:2017(E)Except where stated, glass equipment should be avoided, as it could contaminate the solutions.To obtain reliable values, the equipment should be cleaned and checked as follows.a) Rinse all volumetric ware, including the pipettes used for preparing the calibration solutions, with dil
36、ute hydrochloric acid (5.3) before use. Check the calibration regularly or as needed.b) Clean PTFE vessels and stirring bars by stirring with 50 ml of dilute hydrochloric acid (5.3) and by heating for 15 min. Discard the rinsings and conduct a blank test in each vessel in turn, exactly as specified
37、in 8.3. If any absorbance value is above the limit specified in 8.3, the cleaning procedure should be repeated or acid reagents of a higher purity should be used. At no stage should the stirring bars be handled with the fingers.c) Platinum vessels, exclusively used for potassium analysis according t
38、o this document, can be cleaned by the same method as the PTFE vessels see b). Otherwise, they should be pre-cleaned by fusion with lithium tetraborate or lithium borate, until the absorbance readings fall to those for the lithium salt alone.d) Rinse storage bottles with dilute hydrochloric acid (5.
39、3) before use.6.7 Atomic absorption spectrometer.WARNING Follow the manufacturers instructions for igniting and extinguishing the air/acetylene flame to avoid possible explosion hazards. Wear tinted safety glasses whenever the burner is in operation.The atomic absorption spectrometer shall meet the
40、following criteria.a) Minimum sensitivity: The absorbance of the most concentrated calibration solution (see 8.4.4) shall be at least 0,25.b) Graph linearity: The slope of the calibration graph covering the top 20 % of the concentration range (expressed as a change in absorbance) shall not be less t
41、han 0,7 of the value of the slope for the bottom 20 % of the concentration range determined in the same way.c) Minimum stability: The standard deviation of the absorbance of the most concentrated calibration solution and that of the zero calibration solution, each being calculated from a sufficient
42、number of repetitive measurements, shall be less than 1,5 % and 0,5 %, respectively, of the mean value of the absorbance of the most concentrated calibration solution.The use of a strip-chart recorder and/or digital readout device is recommended to evaluate criteria a), b) and c) and for all subsequ
43、ent measurements.NOTE Instrument parameters will vary with each instrument. The following parameters were successfully used in several laboratories and they can be used as guidelines. Solutions were aspirated into an air/acetylene flame of a premix burner. hollow cathode lamp, mA 10 wavelength, nm 7
44、66,5 air flow-rate, l/min 10 acetylene flow-rate, l/min 2In systems where the values shown for gas flow-rates do not apply, the ratio of the gas flow-rates can still be a useful guideline. ISO 2017 All rights reserved 3BS ISO 13312:2017ISO 13312:2017(E)7 Sampling and samples7.1 Laboratory sampleFor
45、analysis, use a laboratory sample of 100 m particle size which has been taken and prepared in accordance with ISO 3082. In the case of ores having significant contents of combined water or oxidizable compounds, use a particle size of 160 m.NOTE A guideline on significant contents of combined water a
46、nd oxidizable compounds is incorporated in ISO 7764.7.2 Preparation of predried test samplesThoroughly mix the laboratory sample and, taking multiple increments, extract a test sample in such a manner that it is representative of the whole contents of the container. Dry the test sample at 105 C 2 C
47、as specified in ISO 7764. (This is the predried test sample.)For ores having significant content of combined water or oxidizable compounds, an air-equilibrated test sample shall be prepared in accordance with ISO 2596.8 Procedure8.1 Number of determinationsCarry out the analysis at least in duplicat
48、e in accordance with Annex A, independently, on one predried test sample.NOTE The expression “independently” means that the second and any subsequent result are not affected by the previous result(s). For the particular analytical method, this condition implies that the repetition of the procedure i
49、s carried out either by the same operator at a different time or by a different operator including, in either case, appropriate recalibration.8.2 Test portionTaking several increments, weigh, to nearest 0,000 2 g, 0,2 g to 0,5 g (depending on the potassium concentration) of the predried test sample obtained in accordance with 7.2.The test portion should be taken and weighed quickly to avoid reabsorption of moisture.8.3 Blank test and check testBefore proceeding to the treatment of test port
