1、BRITISH STANDARD BS 6200-3.11.3: 1997 ISO 11652: 1997 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.11 Determination of cobalt Subsection 3.11.3 Flame atomic absorption spectrometric method ICS 77.080.01BS6200-3.11.3:1997 This British Standard, h
2、aving been prepared under the directionof the Engineering SectorBoard, was published underthe authority of the Standards Board and comes intoeffect on 15 December 1997 BSI 04-1999 ISBN 0 580 29034 4 National foreword This British Standard reproduces verbatim ISO11652:1997 and implements it as the UK
3、 national standard. The UK participation in its preparation was entrusted to Technical Committee ISE/18, Sampling and analysis of iron and steel, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the in
4、terpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards
5、which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard doe
6、s not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an insi
7、de front cover, pages i and ii, theISO title page, pages ii to iv, pages 1 to 12, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments i
8、ssued since publication Amd. No. Date CommentsBS6200-3.11.3:1997 BSI 04-1999 i Contents Page National foreword Inside front cover Foreword iii Text of ISO 11652 1ii blankBS6200-3.11.3:1997 ii BSI 04-1999 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Reagents 1 5 Appar
9、atus 2 6 Sampling 3 7 Procedure 3 8 Expression of results 7 9 Test report 8 Annex A (normative) Procedures for the determination of instrumental criteria 9 Annex B (informative) Additional information on international cooperative tests 11 Annex C (informative) Graphical representation of precision d
10、ata 13 Figure A.1 Calibration graph 10 Figure C.1 Logarithmic relationship between cobalt content () andrepeatability limit (r) or reproducibility limits (R and R w ) 13 Table 1 Calibration solutions, up to 0,08 % (m/m) cobalt content 4 Table 2 Calibration solutions, 0,08 % (m/m) up to 0,40 % (m/m)
11、cobalt content 4 Table 3 Calibration solutions, 0,40 % (m/m) up to 2,00 % (m/m) cobalt content 5 Table 4 Calibration solutions, 2,0 % (m/m) up to 5,0 % (m/m) cobalt content 5 Table 5 Spectrometer charcteristics 5 Table 6 Results for repeatability limit and reproducibility limits 8 Table B.1 Test sam
12、ples used in the interlaboratory tests 11 Table B.2 Detailed results obtained in interlaboratory tests 12 w CoBS6200-3.11.3:1997 BSI 04-1999 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies (ISO member bodies). The work of p
13、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,
14、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. Draft International Standards adopted by the technical committees are circulated to the member bodies for voting. Pub
15、lication as an International Standard requires approval by at least 75 % of the member bodies casting a vote. International Standard ISO11652 was prepared by Technical Committee ISO/TC 17, Steel, Subcommittee SC 1, Methods of determination of chemical composition. Annex A forms an integral part of t
16、his International Standard. Annex B and Annex C are for information only. Descriptors: Steels, iron, chemical analysis, determination of content, cobalt, atomic absorption spectrometric method.iv blankBS6200-3.11.3:1997 BSI 04-1999 1 1 Scope This International Standard specifies a flame atomic absor
17、ption spectrometric method for the determination of the cobalt content in steel and iron. The method is applicable to cobalt contents between0,003 % (m/m) and 5,0 % (m/m). 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions o
18、f this International Standard. At the time of publication, the editions indicated were valid. All standards are subject to revision, and parties to agreements based on this International Standard are encouraged to investigate the possibility of applying the most recent editions of the standards indi
19、cated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO 385-1:1984, Laboratory glassware Burettes Part 1: General requirements. ISO 648:1977, Laboratory glassware One-mark pipettes. ISO 1042: 1) , Laboratory glassware One-mark volumetric flasks. ISO 369
20、6:1987, Water for analytical laboratory use Specification and test methods. ISO 5725-1:1994, Accuracy (trueness and precision) of measurement methods and results Part 1: General principles and definitions. ISO 5725-2:1994, Accuracy (trueness and precision) of measurement methods and results Part 2:
21、Basic method for the determination of repeatability and reproducibility of a standard measurement method. ISO 5725-3:1994, Accuracy (trueness and precision) of measurement methods and results Part 3: Intermediate measures of the precision of a standard measurement method. ISO 14284:1996, Steel and i
22、ron Sampling and preparation of samples for the determination of chemical composition. 3 Principle Dissolution of a test portion in hydrochloric, nitric and perchloric acids. Spraying of the solution into an air-acetylene flame. Spectrometric measurement of the atomic absorption of the 240,7 nm spec
23、tral line emitted by a cobalt hollow cathode lamp. 4 Reagents During the analysis, unless otherwise stated, use only reagents of recognized analytical grade and only grade 2 water as specified in ISO3696. 4.1 Pure iron, containing less than 0,000 3 % (m/m) cobalt. 4.2 Pure nickel, containing less th
24、an 0,000 3 % (m/m) cobalt. 4.3 Hydrochloric acid, about 1,19 g/ml. 4.4 Nitric acid, about 1,40 g/ml. 4.5 Perchloric acid, about 1,67 g/ml. 4.6 Cobalt, standard solutions. 4.6.1 Standard solution A, corresponding to 1,0 g of Co per litre. Weigh, to the nearest 0,001 g, 1,000 g of metallic cobalt puri
25、ty 99,9 % (m/m) Co. Transfer to a 250 ml beaker. Add 15 ml of water and 15 ml of nitric acid (4.4). Cover the beaker with a watch-glass, heat gently until complete dissolution has taken place and boil to remove oxides of nitrogen. Cool to room temperature, transfer the solution quantitatively to a 1
26、 000 ml one-mark volumetric flask, dilute to the mark with water and mix. 1 ml of this standard solution A contains 1,0 mg ofCo. 1) To be published. (Revision of ISO1042:1983)BS6200-3.11.3:1997 2 BSI 04-1999 4.6.2 Standard solution B, corresponding to 0,2 g of Co per litre. Transfer 20,0 ml of the s
27、tandard solution A (4.6.1) to a 100 ml one-mark volumetric flask, dilute to the mark with water and mix. 1 ml of this standard solution B contains 0,2 mg ofCo. 4.6.3 Standard solution C, corresponding to 0,08 g ofCo per litre. Transfer 8,0 ml of the standard solution A (4.6.1) to a 100 ml one-mark v
28、olumetric flask, dilute to the mark with water and mix. Prepare this standard solution C immediately before use. 1 ml of this standard solution C contains 0,08 mg ofCo. 5 Apparatus All volumetric glassware shall be class A, in accordance with ISO385-1, ISO 648 or ISO1042 as appropriate. Ordinary lab
29、oratory apparatus, and 5.1 Atomic absorption spectrometer, equipped with a cobalt hollow cathode lamp and supplied with air and acetylene sufficiently pure to give a steady clear fuel-lean flame, free from water and oil, and free from cobalt. The atomic absorption spectrometer used will be satisfact
30、ory if, after optimization according to 7.3.4, the limit of detection and characteristic concentration are in reasonable agreement with the values given by the manufacturer and if it meets the precision criteria given in 5.1.1 to 5.1.3. It is also desirable that the instrument should conform to the
31、additional performance requirements given in 5.1.4. 5.1.1 Minimum precision (see A.1) Calculate the standard deviation of 10 measurements of the absorbance of the most concentrated calibration solution. The standard deviation shall not exceed 1,5 % of the mean absorbance. Calculate the standard devi
32、ation of 10 measurements of the absorbance of the least concentrated calibration solution (excluding the zero member). The standard deviation shall not exceed 0,5 % of the mean absorbance of the most concentrated calibration solution. 5.1.2 Limit of detection (see A.2) This is defined as twice the s
33、tandard deviation of 10 measurements of the absorbance of a solution containing the appropriate element of a concentration level selected to give an absorbance just above that of the zero member. The limit of detection of cobalt in a matrix similar to the final test solution shall be better than 0,0
34、5 4g of Co per millilitre, for wavelength240,7 nm. 5.1.3 Graph linearity (see A.3) The slope of the calibration graph covering the top20 % of the concentration range (expressed as a change in absorbance) shall not be less than 0,7 times the value of the slope for the bottom 20 % of the concentration
35、 range (expressed as a change in absorbance) determined in the same way. For instruments with automatic calibration using two or more standards, it shall be established prior to the analysis, by obtaining absorbance readings, that the above requirements for graph linearity are fulfilled. 5.1.4 Chara
36、cteristic concentration (see A.4) The characteristic concentration of cobalt in a matrix similar to the final test portion solution shall be better than 0,3 4g of Co per millilitre, for wavelength 240,7 nm. 5.2 Ancillary equipment A strip chart recorder and/or digital readout device is recommended t
37、o evaluate the criteria of 5.1.1 to5.1.3 and for all subsequent measurements.BS6200-3.11.3:1997 BSI 04-1999 3 Scale expansion may be used until the noise observed is greater than the readout error and is always recommended for absorbances below 0,1. If scale expansion has to be used and the instrume
38、nt does not have the means to read the value of the scale expansion factor, the value can be calculated by measuring the absorbances of a suitable solution with and without scale expansion and simply dividing the signal obtained. A background corrector equipped with a deuterium hollow cathode lamp i
39、s advisable for the analysis of highly alloyed steels, in order to eliminate interference from an FeO molecular absorption band at the cobalt wavelength. 6 Sampling Carry out sampling in accordance with ISO14284 or appropriate national standards for steel and iron. 7 Procedure WARNING Perchloric aci
40、d vapour may cause explosions in the presence of ammonia, nitrous fumes or organic material in general. 7.1 Test portion Weigh a test portion according to the presumed cobalt content as follows: a) for cobalt contents up to 2,0% (m/m), a test portion of about 1,0 g, to the nearest 0,001 g; b) for co
41、balt contents from 2,0% (m/m) to 5,0% (m/m), a test portion of about 0,50 g, to the nearest0,000 5 g. 7.2 Blank test In parallel with the determination and following the same procedure, carry out a blank test for each concentration range (see 7.1) using the same quantities of all the reagents, inclu
42、ding the pure iron (4.1) but omitting the test portion. 7.3 Determination 7.3.1 Preparation of the test solution 7.3.1.1 Dissolution of the test portion Transfer the test portion (7.1) to a 250 ml beaker. Add 10 ml of hydrochloric acid (4.3) and 4 ml of nitric acid (4.4) and cover the beaker with a
43、watch-glass. After effervescence ceases, add 10 ml of perchloric acid(4.5) and heat. Heat until dense white fumes of perchloric acid reflux smoothly in the beaker. Allow to cool, add 30 ml of water and heat gently to dissolve the salts. Cool again and transfer quantitatively to a 100 ml one-mark vol
44、umetric flask. Dilute to the mark with water and mix. Decant the solution through a dry medium-filter paper, to remove any residue or precipitate, for example graphite, silica or tungstic acid, and collect the filtrate in a dry beaker after discarding the first few millilitres. 7.3.1.2 Dilution of t
45、he test solution Depending on the cobalt content expected in the test portion, prepare the test solution in accordance with a), b), c) or d), as follows. a) If the expected cobalt content is up to 0,08 % (m/m), use the filtrate (see 7.3.1.1) undiluted. b) If the expected cobalt content is between 0,
46、08 % (m/m) and 0,40 % (m/m), dilute the filtrate as follows. Transfer 20,0 ml of the filtrate to a 100 ml one-mark volumetric flask, dilute to the mark with water and mix (see note 1). c) If the expected cobalt content is between 0,40 % (m/m) and 2,0 % (m/m), dilute the filtrate as follows. Transfer
47、 10,0 ml of the filtrate to a 250 ml one-mark volumetric flask, dilute to the mark with water and mix (see note 1). d) If the expected cobalt content is between 2,0 % (m/m) and 5,0 % (m/m), dilute the filtrate as follows. Transfer 5,0 ml of the filtrate to a 250 ml one-mark volumetric flask, dilute
48、to the mark with water and mix (see note 1). NOTE 1If the filtrate (see 7.3.1.1) has to be diluted to give the test solution, dilute the blank (see 7.2) in exactly the same way.BS6200-3.11.3:1997 4 BSI 04-1999 7.3.2 Preparation of the calibration solution 7.3.2.1 Cobalt contents up to 0,08 % (m/m) I
49、ntroduce (1,00 0,001) g of the pure iron (4.1) into a series of six 250 ml beakers. Add 10 ml of hydrochloric acid (4.3) and 5 ml of nitric acid (4.4) to each beaker and cover them with watch-glasses. After effervescence ceases, cool, then respectively add, using a burette, the volumes of cobalt standard solution C (4.6.3) given in Table 1. Proceed as specified in 7.3.1.1 from “add 10 ml of perchloric acid (4.5) .” (omitting the filtration step) to item a) in 7.3.1.2. Table 1 Calibration solutions, up to 0,08 % (m/m
