1、 Reference number ISO 5418-2:2006(E) ISO 2006INTERNATIONAL STANDARD ISO 5418-2 First edition 2006-12-01 Iron ores Determination of copper Part 2: Flame atomic absorption spectrometric method Minerais de fer Dosage du cuivre Partie 2: Mthode par spectromtrie dabsorption atomique dans la flamme ISO 54
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5、below. ISO 2006 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 ISOs member bo
6、dy 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 2006 All rights reservedISO 5418-2:2006(E) ISO 2006 All rights reserved iii Contents Page Fo
7、reword iv 1 Scope1 2 Normative references1 3 Principle1 4 Reagents.2 5 Apparatus.3 6 Sampling and samples3 6.1 Laboratory sample.3 6.2 Preparation of predried test samples 4 7 Procedure.4 7.1 Number of determinations 4 7.2 Blank test and check test4 7.3 Test portion 4 7.4 Determination.4 7.4.1 Decom
8、position of the test portion .4 7.4.2 Treatment of the solution5 7.4.3 Preparation of the set of calibration solutions .5 7.4.4 Adjustment of atomic absorption spectrometer 5 7.4.5 Atomic absorption measurements.6 8 Expression of results6 8.1 Calculation of mass fraction of copper .6 8.2 General tre
9、atment of results.6 8.2.1 Repeatability and permissible tolerance.6 8.2.2 Determination of analytical result7 8.2.3 Between-laboratories precision.7 8.2.4 Check for trueness 8 8.2.5 Calculation of final result8 8.3 Oxide factor9 9 Test report9 Annex A (normative) Flowsheet of the procedure for the a
10、cceptance 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 ISO 5418-2:2006(E) iv ISO 2006 All rights reservedForeword ISO (the Internat
11、ional 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 bee
12、n 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 stand
13、ardization. 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
14、 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
15、 such patent rights. ISO 5418-2 was prepared by Technical Committee ISO/TC 102, Iron ore and direct reduced iron, Subcommittee SC 2, Chemical analysis. This first edition cancels and replaces ISO 4693:1986, which has been technically revised. It has been updated to alter the manner in which precisio
16、n data are presented. ISO 5418 consists of the following parts, under the general title Iron ores Determination of copper: Part 1: 2,2-Biquinolyl spectrophotometric method Part 2: Flame atomic absorption spectrometric method INTERNATIONAL STANDARD ISO 5418-2:2006(E) ISO 2006 All rights reserved 1 Ir
17、on ores Determination of copper Part 2: Flame atomic absorption spectrometric method WARNING This part of ISO 5418 may involve hazardous materials, operations and equipment. This part of ISO 5418 does not purport to address all of the safety problems associated with its use. It is the responsibility
18、 of the user of this part of ISO 5418 to establish appropriate health and safety practices and determine the applicability of regulatory limitations prior to use. 1 Scope This part of ISO 5418 specifies a flame atomic absorption spectrometric method for the determination of the mass fraction of copp
19、er in iron ores. This method is applicable to a mass-fraction range of 0,004 % to 0,8 % of copper in natural iron ores, and iron ore concentrates and agglomerates, including sinter products. 2 Normative references The following referenced documents are indispensable for the application of this docum
20、ent. 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
21、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 A test portion is decomposed by treatment with hydrochloric, nitric and hydrofluoric acids. The so
22、lution is evaporated with perchloric acid and diluted, and any insoluble residue is filtered. The copper concentration of the solution is measured by atomic absorption spectrometry using an air- acetylene flame. ISO 5418-2:2006(E) 2 ISO 2006 All rights reserved4 Reagents During the analysis, use onl
23、y reagents of recognized analytical grade, and only water that complies with grade 2 of ISO 3696. The distillation apparatus used should not contain any copper, and deionized water should not come into contact with copper tubing or taps. 4.1 Iron metal powder, mass fraction of copper 0,001 %. 4.2 So
24、dium carbonate (Na 2 CO 3 ), anhydrous. 4.3 Hydrochloric acid, 1,16 g/ml to 1,19 g/ml. 4.4 Hydrochloric acid, 1,16 g/m/l to 1,19 g/ml, diluted 1 + 2. 4.5 Nitric acid, 1,4 g/ml. 4.6 Nitric acid, 1,4 g/ml, diluted 1 + 1. 4.7 Perchloric acid, 60 % (m/m) solution, 1,54 g/ml, or 70 % (m/m) solution, 1,67
25、 g/ml. 4.8 Hydrofluoric acid, 40 % (m/m) solution, 1,13 g/ml or 48 % (m/m) solution, 1,185 g/ml. 4.9 Background solution Dissolve 15 g of iron metal power (4.1) in 150 ml of hydrochloric acid (4.4). Cool the solution to room temperature and add 10 ml of nitric acid (4.5). Heat carefully to eliminate
26、 nitrous gases, add 250 ml of perchloric acid solution (4.7) and evaporate the solution until it fumes. Allow to fume for 10 min, cool and dilute to 1 000 ml with water. 4.10 Copper standard solutions 4.10.1 Stock solution Dissolve 1,000 g of pure metallic copper in 30 ml of dilute nitric acid (4.6)
27、, heat to remove nitrous gases, cool and transfer to a 1 000 ml volumetric flask. Dilute to the mark with water and mix. 1 ml of the stock solution contains 1,00 mg of copper. 4.10.2 Standard solution A Transfer 100 ml of stock solution (4.10.1) to a 1 000 ml volumetric flask. Dilute to the mark wit
28、h water and mix. 1 ml of this standard solution contains 0,10 mg of copper. 4.10.3 Standard solution B Transfer 10 ml of standard solution A (4.10.2) to a 100 ml volumetric flask. Dilute to the mark with water and mix. 1 ml of this standard solution contains 0,010 mg of copper. ISO 5418-2:2006(E) IS
29、O 2006 All rights reserved 3 5 Apparatus Ordinary laboratory equipment, including pipettes and volumetric flasks complying with the accuracy specifications of ISO 648 and ISO 1042, and the following. 5.1 Polytetrafluoroethylene (PTFE) beakers, of capacity 150 ml. 5.2 Atomic absorption spectrometer.
30、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 used will be satisfactory if it meets the following criteria. a
31、) Minimum sensitivity: the absorbance of the calibration solution of highest copper concentration (see 7.4.3), when measured in a flame of 10 cm path length, is at least 0,3. b) Curve linearity: the slope of the calibration graph covering the top 20 % concentration range (expressed as a change in ab
32、sorbance) is not less than 0,7 of the value of the slope for the bottom 20 % concentration range determined in the same way. c) Minimum stability: the standard deviation of the absorbance of the calibration solution of highest concentration and the standard deviation of the absorbance of the zero ca
33、libration 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 calibration solution of highest concentration. The use of a strip-chart recorder and/or digital read-out device is re
34、commended to evaluate these criteria and for all subsequent measurements. NOTE 1 A background corrector equipped with a hydrogen or a deuterium hollow-cathode lamp is advisable for the mass-fraction range of 0,003 % to 0,010 % of copper. NOTE 2 Instrument parameters may vary with each instrument. Th
35、e 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. Copper hollow-cathode lamp (mA) 3 Wavelength (nm) 324,7 Air flow rate (l/min) 10 Acetylene flow rate (l/min) 2 In systems
36、 where the values shown 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 minus 100 m particle size which has been taken and prepared in accordance with ISO 3082. In
37、the case of ores having significant contents of combined water or oxidizable compounds, use a particle size of minus 160 m. NOTE A guideline on significant contents of combined water and oxidizable compounds is given in ISO 7764. ISO 5418-2:2006(E) 4 ISO 2006 All rights reserved6.2 Preparation of pr
38、edried test samples Thoroughly 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 2 C as specified in ISO 7764. (This is the predried test sample.) 7 Procedure
39、7.1 Number of determinations Carry out the analysis at least in duplicate in accordance with Annex A, independently, on one predried test sample. NOTE The expression “independently” means that the second and any subsequent result is not affected by the previous result(s). For this particular analyti
40、cal method, this condition implies that the repetition of the procedure is carried out either by the same operator at a different time or by a different operator including, in either case, appropriate recalibration. 7.2 Blank test and check test In each run, one blank test and one analysis of a cert
41、ified reference material of the same type of ore shall be carried out in parallel with the analysis of the ore sample(s) under the same conditions. A predried test sample of the certified reference material shall be prepared as specified in 6.2 (see the last paragraph of this subclause). Where the a
42、nalysis is carried out on several samples at the same time, the blank value may be represented by one test, provided that the procedure is the same and the reagents used are from the same reagent bottles. Where the analysis is carried out on several samples of the same type of ore at the same time,
43、the analytical value of one certified reference material may be used. The certified reference material should be of the same type as the sample to be analysed, and the properties of the two materials should be sufficiently similar to ensure that, in either case, no significant changes in the analyti
44、cal procedure become necessary. 7.3 Test portion Taking several increments, weigh, to the nearest 0,000 2 g, approximately 0,5 g of the predried test sample obtained in accordance with 6.2. The test portion should be taken and weighed quickly to avoid reabsorption of moisture. 7.4 Determination 7.4.
45、1 Decomposition of the test portion Transfer the test portion (7.3) to a 150 ml PTFE beaker (5.1). Moisten with a few millilitres of water, add 15 ml of hydrochloric acid (4.3), cover with a watch-glass, and heat gently. Increase the heat and digest just below boiling until no further attack is appa
46、rent. Add 5 ml of nitric acid (4.5) and heat for 10 min. Remove the watch- glass, add 3 ml of hydrofluoric acid (4.8) and heat for a further 10 min. Wash down the walls of the beaker with water and add 5 ml of perchloric acid (4.7). Heat slowly, evaporating until dense white fumes of perchloric acid
47、 are evolved. Allow to fume for 2 min to 3 min. Allow the solution to cool, add 50 ml of water and heat gently to dissolve the soluble salts. ISO 5418-2:2006(E) ISO 2006 All rights reserved 5 Filter the solution through a close-texture paper, collecting the filtrate and washings in a 100 ml volumetr
48、ic flask. Wash the paper and the residue thoroughly with warm water. Cool the final solution, dilute to volume with water and mix. (This is the test solution.) If a significant amount of residue remains from the decomposition process, or if any residue is suspected to contain a significant amount of
49、 copper, examine such residue separately for mass fraction of copper after ignition, fusion with the sodium carbonate (4.2), and dissolution of the melt in nitric acid diluted 1 + 50. An appropriate blank test solution should also be prepared. The result obtained from a copper determination on any insoluble residue is then combined with the result obtained for copper in the main test solution. 7.4.2 Treatment of the solution If the mass fraction of copper is greater than 0,2 % (or 0,1 % in the ca
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