1、BRITISH STANDARD BS ISO 11438-7:1993 Implementation of ISO11438-7:1993 Ferronickel Determination of trace-element content by electrothermal atomic absorption spectrometric method Part7: Determination of silver content UDC 669.245:543.422.064:546.57BSISO11438-7:1993 This BritishStandard, having been
2、prepared under the directionof the Non-ferrous Metals Standards Policy Committee, was published underthe authority of the Standards Board and comesintoeffect on 15May1994 BSI 02-2000 The following BSI references relate to the work on this standard: Committee reference NFM/10 Draft for comment92/4209
3、2 DC ISBN 0 580 23357 X Committees responsible for this BritishStandard The preparation of this BritishStandard was entrusted by the Non-ferrous Metals Standards Policy Committee (NFM/-) to Technical Committee NFM/10, upon which the following bodies were represented: Association of Bronze and Brass
4、Founders British Non-ferrous Metals Federation British Stainless Steel Association British Steel Industry Department of Trade and Industry (Laboratory of the Government Chemist) Engineering Equipment and Materials Users Association Institute of British Foundrymen London Metal Exchange Ministry of De
5、fence Nickel Development Institute Non-ferrous Metal Stockists Steel Casting Research and Trade Association Coopted members Amendments issued since publication Amd. No. Date CommentsBSISO11438-7:1993 BSI 02-2000 i Contents Page Committees responsible Inside front cover National foreword ii Foreword
6、iii Text of ISO 11438-7 1BSISO11438-7:1993 ii BSI 02-2000 National foreword This BritishStandard reproduces verbatim ISO11438-7:1993 and implements it as the UK national standard. This BritishStandard is published under the direction of the Non-ferrous Metals Standards Policy Committee whose Technic
7、al Committee NFM/10 has the responsibility to: aid enquirers to understand the text; present to the responsible international committee any enquiries on interpretation, or proposals for change, and keep UK interests informed; monitor related international and European developments and promulgate the
8、m in the UK. NOTEInternational and European Standards, as well as overseas standards, are available from Customer Services, Publications, BSI, Linford Wood, Milton Keynes, MK146LE. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards a
9、re 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 inside front cover, pagesi andii, theISO title page, pagesii to iv, pages1 and 2 and a back cover. Th
10、is 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.ISO11438-7:1993(E) ii BSI 02-2000 Contents Page Foreword iii 1 Scope 1 2 Normative references 1 3 Principle 1 4 Reagents 1 5 Apparatus 1
11、 6 Sampling and sample preparation 1 7 Procedure 1 7.1 Preparation of the test solution 1 7.2 Blank test 1 7.3 Determination by the standard additions method 1 7.3.1 Atomic absorption measurements 1 7.3.2 Semi-quantitative estimation of the silver content 1 7.3.3 Quantitative determination of the si
12、lver content 1 7.3.4 Plotting of standard additions 1 7.4 Number of determinations 1 8 Expression of results 2 8.1 Calculation 2 8.1.1 Semi-quantitative estimation of the silver content 2 8.1.2 Quantitative determination of the silver content 2 8.1.3 Calculation of the silver content 2 8.2 Precision
13、 2 8.2.1 Laboratory tests 2 8.2.2 Statistical analysis 2 9 Test report 2 Table 1 Nominal composition of test samples 2 Table 2 Results of statistical analysis 2ISO11438-7:1993(E) BSI 02-2000 iii Foreword ISO (the International Organization for Standardization) is a worldwide federation of national s
14、tandards 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
15、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. Draft International Standards adopted by the technical committees a
16、re circulated to the member bodies for voting. Publication as an International Standard requires approval by at least75% of the member bodies casting a vote. International Standard ISO11438-7 was prepared by Technical Committee ISO/TC155, Nickel and nickel alloys, Sub-Committee SC3, Analysis of nick
17、el and ferronickel. ISO11438 consists of the following parts, under the general title Ferronickel Determination of trace-element content by electrothermal atomic absorption spectrometric method: Part1: General requirements and sample dissolution; Part2: Determination of lead content; Part3: Determin
18、ation of antimony content; Part4: Determination of tin content; Part5: Determination of tellurium content; Part6: Determination of thallium content; Part7: Determination of silver content; Part8: Determination of indium content.iv blankISO11438-7:1993(E) BSI 02-2000 1 1 Scope This part of ISO11438 s
19、pecifies an electrothermal atomic absorption spectrometric method for the determination of silver in the range of1,0g/t to6,0g/t in ferronickel, according to the principle of standard additions. The general requirements concerning the apparatus, sampling, dissolution of the test sample, procedure, c
20、alculation and test report are given in ISO11438-1. 2 Normative references The following standards contain provisions which, through reference in this text, constitute provisions of this part of ISO11438. At the time of publication, the editions indicated were valid. All standards are subject to rev
21、ision, and parties to agreements based on this part of ISO11438 are encouraged to investigate the possibility of applying the most recent editions of the standards indicated below. Members of IEC and ISO maintain registers of currently valid International Standards. ISO5725:1986, Precision of test m
22、ethods Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests. ISO11438-1:1993, Ferronickel Determination of trace-element content by electrothermal atomic absorption spectrometric method Part1: General requirements and sample dissolution. 3 Principle
23、 Dissolution of a test portion in nitric acid. Measurement of the absorption of the resonance line energy from the spectrum of silver in the test solution at a wavelength of328,1nm by an atomic absorption spectrometer fitted with a graphite furnace electrothermal atomizer. Calibration by the standar
24、d additions method described in ISO11438-1. 4 Reagents In addition to the reagents listed in ISO11438-1, the following special reagents are required. 4.1 Silver, standard reference solution(1000mg/l). Weigh, to the nearest0,001g,1,000g of silver metal of99,9%(m/m) minimum purity. Transfer to a250ml
25、beaker and dissolve in a mixture of10ml of nitric acid ( 20 =1,41g/ml) and20ml of water. Heat until completely dissolved. Boil to expel nitrogen oxides. Cool the solution and transfer to a1000ml one-mark volumetric flask. Add10ml of nitric acid ( 20 =1,41g/ml) make up to the mark with water and mix
26、thoroughly. 4.2 Silver, standard solution(10,0mg/l). Pipette10,0ml of the silver standard reference solution(4.1) into a1000ml one-mark volumetric flask containing50ml of nitric acid( 20 =1,41g/ml) diluted1+1. Make up to the mark with water and mix thoroughly. This solution shall be prepared on the
27、day of use. 4.3 Silver, working standard solution(1,0mg/l). Pipette10,0ml of the silver standard solution(4.2) into a100ml one-mark volumetric flask containing5ml of nitric acid ( 20 =1,41g/ml) diluted1+1. Make up to the mark with water and mix thoroughly. This solution shall be freshly prepared. 5
28、Apparatus The apparatus required is specified in clause5 of ISO11438-1:1993. 6 Sampling and sample preparation Refer to clause6 of ISO11438-1:1993. 7 Procedure 7.1 Preparation of the test solution Proceed as directed in7.1 of ISO11438-1:1993. 7.2 Blank test Refer to7.2 of ISO11438-1:1993. 7.3 Determ
29、ination by the standard additions method 7.3.1 Atomic absorption measurements Use the peak area integration absorbance measurement at a wavelength of328,1nm and proceed with checking the electrothermal atomizer as directed in7.3.1 of ISO11438-1:1993. 7.3.2 Semi-quantitative estimation of the silver
30、content Proceed as directed in7.3.2 of ISO11438-1:1993. 7.3.3 Quantitative determination of the silver content Proceed as directed in7.3.3 of ISO11438-1:1993. 7.3.4 Plotting of standard additions Proceed as directed in7.3.4 of ISO11438-1:1993. NOTE 1The procedure is applicable to the linear part of
31、the graphs. 7.4 Number of determinations Carry out the determination at least in duplicate.ISO11438-7:1993(E) 2 BSI 02-2000 8 Expression of results 8.1 Calculation 8.1.1 Semi-quantitative estimation of the silver content Proceed as directed in8.1.1 of ISO11438-1:1993. 8.1.2 Quantitative determinatio
32、n of the silver content Proceed as directed in8.1.2 of ISO11438-1:1993. 8.1.3 Calculation of the silver content Calculate the silver content w Agof the test sample, in grams per tonne, using the formula 8.2 Precision 8.2.1 Laboratory tests Six laboratories in five countries participated in the testi
33、ng of this procedure using two samples of nominal composition given in Table 1. Samples were analysed three times on different days. 8.2.2 Statistical analysis 8.2.2.1 Results from the interlaboratory test programme were evaluated according to ISO5725 as described in8.2.2 of ISO11438-1:1993. The res
34、ults of this analysis are given in Table 2. 8.2.2.2 One laboratory was rejected as a Cochran outlier for sample1. 9 Test report Refer to clause10 of ISO11438-1:1993. Table 1 Nominal composition of test samples Table 2 Results of statistical analysis where Ag is the silver concentration, in microgram
35、s per litre, found in the “zero” test solution, in accordance with8.1.2 of ISO11438-1:1993; m is the mass, in grams, of the test portion; w Ag F Ag 10m - = F is the dilution factor of2,5. Sample Content, g/t Content,% (m/m) Pb Sb Sn Te TI Ag In Bi As Se Cd Ga Ge Zn Ni Fe 1 1 1 1 0,5 0,5 1 0,5 0,1 3
36、0,5 0,5 2 1 2 25 Remainder 2 6 4 10 2 1 6 2 1 5 3 1 4 4 5 25 Remainder Sample 1 2 Mean w Ag , g/t 0,92 5,91 Within-laboratory standard deviation 0,05 0,4 Between-laboratory standard deviation 0,1 0,9 Repeatability 0,15 1,1 Reproducibility 0,4 2,7blankBS ISO 11438-7:1993 BSI 389 Chiswick High Road Lo
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