1、BRITISH STANDARD BS3338-7: 1961 Method for The determination of silver in solders (Volumetric: ammonium thiocyanate method) Methods for the sampling and analysis of tin and tin alloysBS3338-7:1961 This BritishStandard, having been approved by the Non-ferrous Metals IndustryStandards Committeeand end
2、orsed bytheChairman of the Engineering Divisional Council,was published undertheauthority of the GeneralCouncil on 17February1961 BSI 12-1999 The following BSI references relate to the work on this standard: Committee references NFE/27, NFE/27/1 Draft for comment A(NFE)9204 ISBN 0 580 03077 6 Co-ope
3、rating organizations The Non-ferrous Metals Industry Standards Committee, under whose supervision this BritishStandard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Admiralty* Institution of Mining and Metallurgy Alum
4、inium Development Association Institution of Structural Engineers Aluminium Industry Council Lead Development Association Association of Bronze and Brass Founders Lead Sheet and Pipe Manufacturers Association of Consulting Engineers Federation (Incorporated) Light Metal Founders Association British
5、Bronze and Brass Ingot Manufacturers London Metal Exchange* Association Magnesium Industry Council British Electrical and Allied Manufacturers Ministry of Aviation* Association* National Brassfoundry Association British Non-ferrous Metals Federation Non-ferrous Metal Stockists British Non-ferrous Me
6、tals Research Post Office* Association* Royal Institute of British Architects Cable Makers Association* Society of British Aircraft Constructors Copper Development Association Society of Motor Manufacturers and Crown Agents for Oversea Governments and Traders Ltd.* Administrations Tin Research Insti
7、tute* High Commission of India War Office* High Conductivity Copper Association Zinc Development Association Institute of British Foundrymen Individual manufacturers Institute of Metals Institution of Mechanical Engineers (Automobile Division) The Government departments and scientific and industrial
8、 organizations marked with an asterisk in the above list, together with the following, were directly represented on the committee entrusted with the preparation of this BritishStandard: British Railways, The British Transport Solder Makers Association Commission Tinplate Conference(1925) British Tin
9、 Box Manufacturers Federation Tin Producers Association Electronic Engineering Association White Metal Bearing Manufacturers Gas Council Individual manufacturers Institution of Gas Engineers London Transport Executive, The British Transport Commission Amendments issued since publication Amd. No. Dat
10、e CommentsBS3338-7:1961 BSI 12-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii Introduction 1 Apparatus 1 Solutions required 1 Sampling 1 Procedure 1BS3338-7:1961 ii BSI 12-1999 Foreword This standard makes reference to the following BritishStandard: BS3338, Methods fo
11、r the sampling and analysis of tin and tin alloys Part12: Sampling of solders. This method for the determination of silver in solders is the seventh of a series of methods which will form a complete BritishStandard under the collective title “Methods for the sampling and analysis of tin and tin allo
12、ys”, each method being published as a separate part. The preparation of this series of methods has been authorized by the Non-ferrous Metals Industry Standards Committee as part of a general programme for the standardization of methods for the sampling and analysis of non-ferrous metals. Other metho
13、ds in the series are as follows: Part1: Sampling of ingot tin; Part2: Determination of tin in ingot tin; Part3: Determination of antimony in ingot tin; Part4: Determination of copper in ingot tin and tin-lead solders; Part5: Determination of lead in ingot tin and tin-antimony solders; Part6: Determi
14、nation of copper in high purity ingot tin; Part8: Determination of bismuth in ingot tin, tin-lead solders and white metal bearing alloys; Part9: Determination of arsenic in ingot tin, tin-lead solders and white metal bearing alloys; Part10: Determination of iron in ingot tin, tin-lead solders and wh
15、ite metal bearing alloys; Part11: Determination of tin in solders; Part12: Sampling of solders. The complete BritishStandard methods will be found suitable for the grades of metals covered by BS3252, “Ingot tin”, BS219, “Soft solders”, and BS3332, “White metal bearing alloy ingots”. In the methods f
16、or determining impurities, sample weights and aliquots have been chosen to cover the range of impurity content usually found in commercial tin ingots, solders and white metal bearing alloy ingots. For amounts of impurity outside this range, sample weights of aliquots should be adjusted accordingly.
17、The methods have been found to give reliable and reproducible results, and, while in some instances they may appear to be lengthy, it should be realized that they are put forward as “referee” methods to be used in cases of dispute. A British Standard does not purport to include all the necessary pro
18、visions 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 inside front cover, pagesi andii, pages1 and 2, an
19、 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.BS3338-7:1961 BSI 12-1999 1 Introduction a) Principle. Silver is determined volumetrically with a
20、mmonium thiocyanate. b) Range. Up to3.0per cent silver. c) Reproducibility. 0.02per cent. Apparatus Any volumetric glassware used shall be of Class A accuracy as defined in the appropriate BritishStandards, or where no BritishStandard exists, as described in the National Physical Laboratory Publicat
21、ion “Volumetric Tests on Volumetric Glassware”. Solutions required All reagents shall be of the highest purity obtainable and distilled water shall be used throughout. Solutions shall be freshly prepared and, where necessary, filtered. Ammonium ferric sulphate (10per cent w/v). Dissolve10g of ammoni
22、um ferric sulphate in water, add10ml of nitric acid(sp.gr.1.42), and dilute to100ml. Ammonium thiocyanate (N/10 approximate). Dissolve8g of ammonium thiocyanate in water, and dilute to1litre in a graduated flask. Standardize as described in “Procedure” using pure silver or pure silver nitrate. N/10
23、silver nitrate solution contains per ml0.01079g of silver, or0.01699g of silver nitrate. Nitric acid (20per cent v/v). Dilute20ml of nitric acid(sp.gr.1.42) to100ml. Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS3338-12, “Samp
24、ling of solders”. Procedure Dissolve10.0g of sample in100ml of nitric acid(20per cent) in a500ml conical beaker, boil to expel nitrous fumes, cool, and dilute to200ml. Add5ml of ammonium ferric sulphate solution(10per cent), and titrate with ammonium thiocyanate(N/10), to the appearance of a faint b
25、rown coloration.1ml N/10 ammonium thiocyanate=0.01079g of silver. Carry out a blank determination using the same quantity of lead and tin as contained in the sample, and deduct this from the sample titration.2 blankBS3338-7:1961 BSI 12-1999 BritishStandards The following are available on application
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