ISO-15633-2009.pdf

Reference number ISO 15633:2009(E) © ISO 2009 INTERNATIONAL STANDARD ISO 15633 First edition 2009-01-15 Iron ores Determination of nickel Flame atomic absorption spectrometric method Minerais de fer Dosage du nickel Méthode par spectrométrie d'absorption atomique dans la flamme Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=HP Monitoring/1111111164 Not for Resale, 02/02/2009 20:48:43 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 15633:2009(E) PDF disclaimer This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat accepts no liability in this area. Adobe is a trademark of Adobe Systems Incorporated. Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below. COPYRIGHT PROTECTED DOCUMENT © ISO 2009 All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means, electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or ISO's member body in the country of the requester. ISO copyright office Case postale 56 CH-1211 Geneva 20 Tel. + 41 22 749 01 11 Fax + 41 22 749 09 47 E-mail copyrightiso.org Web www.iso.org Published in Switzerland ii © ISO 2009 All rights reserved Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=HP Monitoring/1111111164 Not for Resale, 02/02/2009 20:48:43 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 15633:2009(E) © ISO 2009 All rights reserved iii Contents Page Foreword iv Introduction v 1 Scope . 1 2 Normative references. 1 3 Principle. 1 4 Reagents 2 5 Apparatus 2 6 Sampling and samples. 3 6.1 Laboratory sample 3 6.2 Preparation of predried test samples. 3 7 Procedure 4 7.1 Number of determinations. 4 7.2 Test portion. 4 7.3 Blank test and check test. 4 7.4 Determination 4 7.4.1 Decomposition of the test portion 4 7.4.2 Removal of iron. 5 7.4.3 Treatment of the residue 5 7.4.4 Preparation of the calibration solutions. 5 7.4.5 Adjustment of the atomic absorption spectrometer. 6 7.4.6 Atomic absorption measurements 6 8 Expression of results . 6 8.1 Calculation of mass fraction of nickel 6 8.2 General treatment of results 7 8.2.1 Repeatability and permissible tolerance 7 8.2.2 Determination of analytical result. 7 8.2.3 Between-laboratories precision 7 8.2.4 Check for trueness . 8 8.2.5 Calculation of final result. 8 8.3 Oxide factor. 9 9 Test report . 9 Annex A (normative) Flowsheet of the procedure for the acceptance of analytical values for test samples 10 Annex B (informative) Derivation of repeatability and permissible tolerance equations. 11 Annex C (informative) Precision data obtained by international analytical trials . 12 Bibliography. 13 Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=HP Monitoring/1111111164 Not for Resale, 02/02/2009 20:48:43 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 15633:2009(E) iv © ISO 2009 All rights reserved 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 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. ISO collaborates closely 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. Draft 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 document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. ISO 15633 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 2, Chemical analysis. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=HP Monitoring/1111111164 Not for Resale, 02/02/2009 20:48:43 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 15633:2009(E) © ISO 2009 All rights reserved v Introduction The objective of a proposed revision of ISO 9685:1991 was to extend the lower limit for a flame atomic absorption spectrometric method determination of both chromium and nickel in iron ores down to 0,001 %. However, due to bias, the method for nickel could not be approved for referee purposes. The 22nd meeting of ISO/TC 102/SC 2 decided to progress the document as a non-referee method. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=HP Monitoring/1111111164 Not for Resale, 02/02/2009 20:48:43 MSTNo reproduction or networking permitted without license from IHS -,-,- Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=HP Monitoring/1111111164 Not for Resale, 02/02/2009 20:48:43 MSTNo reproduction or networking permitted without license from IHS -,-,- INTERNATIONAL STANDARD ISO 15633:2009(E) © ISO 2009 All rights reserved 1 Iron ores Determination of nickel Flame atomic absorption spectrometric method WARNING This International Standard may involve hazardous materials, operations and equipment. This International Standard does not purport to address all of the safety problems associated with its use. It is the responsibility of the user of this International Standard to establish appropriate health and safety practices and determine the applicability of regulatory limitations prior to use. 1 Scope This International Standard specifies a flame atomic absorption spectrometric method for the determination of the nickel mass fraction of iron ores. This method is applicable to mass fractions of nickel between 0,001 % and 0,1 % in natural iron ores, iron ore concentrates and agglomerates, including sinter products. This method is not appropriate for referee purposes. 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 referenced document (including any amendments) applies. ISO 648, Laboratory glassware One-mark pipettes ISO 1042, Laboratory glassware One-mark volumetric flasks ISO 3082, Iron ores Sampling and sample preparation procedures ISO 3696, Water for analytical laboratory use Specification and test methods ISO 7764, Iron ores Preparation of predried test samples for chemical analysis 3 Principle The test portion of iron ore is decomposed by treatment with hydrochloric and nitric acids. The major portion of iron in the filtrate is removed by extraction with 4-methylpentan-2-one. The insoluble residue is ignited and silicon dioxide is removed by evaporation with hydrofluoric and sulfuric acids. The residue is fused with a mixture of sodium carbonate and sodium tetraborate, and then dissolved with hydrochloric acid and combined with the main solution. The solution is aspirated into the flame of an atomic absorption spectrometer using an air-acetylene burner. The absorbance values obtained are compared with those obtained from the calibration solutions. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=HP Monitoring/1111111164 Not for Resale, 02/02/2009 20:48:43 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 15633:2009(E) 2 © ISO 2009 All rights reserved 4 Reagents During the analysis, use only reagents of recognized analytical grade, and only water that conforms to grade 2 of ISO 3696. 4.1 Sodium carbonate (Na2CO3), anhydrous powder. 4.2 Sodium tetraborate (Na2B4O7), anhydrous powder. 4.3 Lithium tetraborate (Li2B4O7), anhydrous powder. 4.4 Hydrochloric acid, = 1,16 g/ml to 1,19 g/ml. 4.5 Hydrochloric acid, = 1,16 g/ml to 1,19 g/ml, diluted 2 + 1. 4.6 Hydrochloric acid, = 1,16 g/ml to 1,19 g/ml, diluted 1 + 1. 4.7 Hydrochloric acid, = 1,16 g/ml to 1,19 g/ml, diluted 2 + 100. 4.8 Nitric acid, = 1,4 g/ml. 4.9 Nitric acid, = 1,4 g/ml, diluted 1 + 1. 4.10 Hydrofluoric acid, = 1,13 g/ml, 40 % (mass fraction), or = 1,19 g/ml, 48 % (mass fraction). 4.11 Sulfuric acid, = 1,84 g/ml. 4.12 Sulfuric acid, = 1,84 g/ml, diluted 1 + 1. 4.13 4-Methylpentan-2-one, (methyl isobutyl ketone, MIBK). 4.14 Nickel standard solution A, 100 µg Ni/ml. Dissolve 0,1 000 g of nickel metal purity 99,9 % (mass fraction) (see Note to 4.15) in 30 ml of nitric acid (4.9). After cooling, transfer quantitatively to a 1 000 ml one-mark volumetric flask, dilute to volume with water and mix. 4.15 Nickel standard solution B, 10 µg Ni/ml. Transfer 100,0 ml of nickel standard solution A (4.14) to a 1 000 ml one-mark volumetric flask. Dilute to volume with water and mix. NOTE The purity of the metals stated on the certificates does not generally take into account the presence of absorbed gases such as oxygen, carbon monoxide, etc. 5 Apparatus Ordinary laboratory apparatus, including one-mark pipettes and one-mark volumetric flasks complying with the specifications of ISO 648 and ISO 1042, and the following. 5.1 Platinum crucible, of minimum capacity 25 ml. 5.2 Muffle furnace. 5.3 Atomic absorption spectrometer, equipped with an air-acetylene burner. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=HP Monitoring/1111111164 Not for Resale, 02/02/2009 20:48:43 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 15633:2009(E) © ISO 2009 All rights reserved 3 WARNING Follow the manufacturer's 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 used in this method shall meet the following criteria. a) Minimum sensitivity: the absorbance of the most concentrated calibration solution (see 7.4.4) is at least 0,3. b) Graph linearity: the slope of the calibration graph covering the top 20 % of the concentration range (expressed as a change in absorbance) is not less than 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 number of repetitive measurements, are less than 1,5 % and 0,5 %, respectively, of the mean value of the absorbance of the most concentrated 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 subsequent measurements. NOTE Instrument parameters vary with each instrument. The following parameters were successfully used in several laboratories and they can be used as guidelines. An air-acetylene flame was used. Hollow-cathode lamp, mA 10 Wavelength, nm 232,0 Air flow rate, l/min 10 Acetylene flow rate, l/min 2,5 In systems where the values shown above for gas flow rates do not apply, the ratio of the gas flow rates may still be a useful guideline. 6 Sampling and samples 6.1 Laboratory sample For analysis, use a laboratory sample of , in which case the difference between the reported result and the reference/certified value is statistically significant. where µc is the analytical result for the CRM; Ac is the certified/reference 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 35. For a CRM certified by an interlaboratory test programme 1/2 2 2d Lc 2()CV A n =+ where V(Ac) is the variance of the certified value Ac (= 0 for a CRM/RM certified by only one laboratory); n is the number of replicate determinations carried out on the CRM/RM; d is the independent duplicate standard deviation; L is the between-laboratories standard deviation. If the certification has been made by only one laboratory or if the interlaboratory results are missing, it is advisable that this material not be used in the application of the standard. In case its use is unavoidable, substitute 2 L for V(Ac). 8.2.5 Calculation of final result The final result is the arithmetic mean of the acceptable analytical values for the test sample, or as otherwise determined by the operations specified in Annex A, calculated to five decimal places and rounded off to the third decimal place according to Rule A in ISO 31-0:1992, B.3 as follows. Copyright International Organization for Standardization Provided by IHS under license with ISO Licensee=HP Monitoring/1111111164 Not for Resale, 02/02/2009 20:48:43 MSTNo reproduction or networking permitted without license from IHS -,-,- ISO 15633:2009(E) © ISO 2009 All rights reserved 9 a) Where the figure in the fourth decimal place is less than 5, it is discarded and the figure in the third decimal place is kept unchanged. b) Where the figure in the fourth decimal place is 5 and there is a figure other than 0 in the fifth decimal place, or where the figu