1、BRITISH STANDARD BS 3338-5: 1961 Method for The determination of lead in ingot tin and tin-antimony solders (photometric method)BS3338-5:1961 This British Standard, having been approved by the Non-ferrous Metals Industry Standards Committee and endorsed by the Chairman oftheEngineering Divisional Co
2、uncil, was published undertheauthority of theGeneralCouncil on 29April1961 BSI 11-1999 The following BSI references relate to the work on this standard: Committee references NFE/27, NFE/27/1 Draft for comment A(NFE)9202 ISBN 0 580 03057 1 Co-operating organizations The Non-ferrous Metals Industry St
3、andards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Admiralty* Institution of Mining and Metallurgy Aluminium Development Association Institution of Structura
4、l 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 Bronze and Brass Ingot Manufacturers London Metal Exc
5、hange* 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 Metals Research Post Office* Association* Royal Institu
6、te of British Architects Cable Makers Association* Society of British Aircraft Constructors Copper Development Association Society of Motor Manufacturers and Traders Crown Agents for Oversea Governments and Ltd.* Administrations Tin Research Institute* High Commission of India War Office* High Condu
7、ctivity 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 organizations marked with an asterisk in the above l
8、ist, together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: British Railways, The British Transport London Transport Executive, The British Commission Transport commission British Tin Box Manufacturers Federation Solder Makers
9、 Association Electronic Engineering Association Tinplate Conference(1925) Gas Council Tin Producers Association Institution of Gas Engineers Individual firms Amendments issued since publication Amd. No. Date CommentsBS3338-5:1961 BSI 11-1999 i Contents Page Co-operating organizations Inside front co
10、ver Foreword ii Introduction 1 Apparatus 1 Solutions required 1 Sampling 1 Procedure 1 Calibration 2BS3338-5:1961 ii BSI 11-1999 Foreword This standard makes reference to the following British Standard: BS3338-1, Sampling of ingot tin. BS3338-12, Sampling of solders. This method for the determinatio
11、n of lead in ingot tin and tin-antimony solders is the fifth of a series of methods which will form a complete British Standard under the collective title “Methods for the sampling and analysis of tin and tin alloys”, each method being published as a separate part. The preparation of this series of
12、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 methods in the series are as follows: Part1: Sampling of ingot tin; Part2: Determination of
13、tin in ingot tin; Part3: Determination of antimony in ingot tin; Part4: Determination of copper in ingot tin and tin-lead solders; Part6: Determination of copper in high purity ingot tin; Part7: Determination of silver in solders; Part8: Determination of bismuth in ingot tin, tin-lead solders and wh
14、ite 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 white metal bearing alloys; Part11: Determination of tin in solders; Part12: Sampling of solders. The complete Bri
15、tish Standard 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 for determining impurities, sample weights and aliquots have been chosen to cover the range of impurity content us
16、ually found in commercial tin ingots, solders and white metal bearing alloy ingots. For amounts of impurity outside this range, sample weights or aliquots should be adjusted accordingly. The methods have been found to give reliable and reproducible results, and, while in some instances they may appe
17、ar to be lengthy, it should be realized that they are put forward as “referee” methods to be used in cases of dispute. In the preparation of the calibration graphs an attempt has been made to define concentrations, but because these are linked with the particular instrument used for determining opti
18、cal density they should be used only as a guide. A British Standard does 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 oblig
19、ations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 and 2 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.BS
20、3338-5:1961 BSI 11-1999 1 Introduction a) Principle. Lead is determined photometrically with dithizone after removal of tin as bromide. b) Range. Up to0.9percent lead. c) Reproducibility. 10per cent of lead present. Apparatus a) Any volumetric glassware used shall be of Class A accuracy as defined i
21、n the appropriate British Standards, or where no British Standard exists, as described in the National Physical Laboratory Publication “Volumetric Tests on Volumetric Glassware”. b) Any instrument suitable for measuring the optical density of the solution at a wavelength of510m4 may be used. c) 4cm
22、or1cm cells (Note1). d) Alternatively, if a filter photometer of the balanced two cell type is used, the filter combination should conform as closely as possible to the above wavelength. The following have been found suitable: Tungsten lamp Ilford604 or equivalent filters. Solutions required All rea
23、gents shall be of the highest purity obtainable and distilled water shall be used throughout. Solutions shall be freshly prepared and, where necessary, filtered. Standard lead (1mlN 0.10mg of lead). Dissolve40.0mg of lead nitrate in nitric acid(5percent v/v), transfer to a250ml graduated flask, and
24、dilute to the mark. Standard lead (1ml N 0.01mg of lead). Dilute25ml of the above solution to250ml in a graduated flask. Bromine-hydrobromic acid. Add10ml of bromine to90ml of hydrobromic acid(48per cent v/v). Dithizone solution (0.006per cent w/v). Dissolve30mg of dithizone in25ml of chloroform and
25、 extract twice in a large separating funnel with100-ml portions of ammonia solution(2percent v/v). Discard the chloroform layer and wash the combined aqueous layers with about20ml of chloroform. Again discard the chloroform layer. Make the aqueous solution just acid by addition of hydrochloric acid
26、(sp. gr.1.161.18) and shake with250ml of chloroform. Separate the chloroform layer, add a further250ml of chloroform and shake again. Separate and combine the two chloroform extracts. Wash with water and store in a dark bottle. Hydroxyammonium chloride (10per cent w/v). Dissolve10g of hydroxyammoniu
27、m chloride in100ml of water. Nitric acid (50per cent v/v). Dilute50ml of nitric acid (sp. gr.1.42) to100ml. Nitric acid (5per cent v/v). Dilute5ml of nitric acid (sp. gr.1.42) to100ml. Potassium cyanide (ammoniacal). Dissolve5g of potassium cyanide and1g of sodium sulphite in400ml of water and add25
28、0ml of ammonia solution (sp. gr.0.91). Sodium tartrate (20per cent w/v). Dissolve20g of sodium tartrate in water and dilute to100ml. Thymol blue indicator. Warm0.1g of thymol blue with4.3ml of sodium hydroxide solution(0.2percent w/v) and5ml of alcohol until dissolved. Dilute with alcohol(20per cent
29、) to250ml. Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS3338-1, “Sampling of ingot tin” and Part12, “Sampling of solders”. Procedure Dissolve0.25g of sample in10ml of bromine-hydrobromic acid in a150ml beaker and evaporate to
30、 dryness. Add a further5ml of bromine-hydrobromic acid and evaporate again. To the residue add5ml of nitric acid(50per cent) and boil until free from bromine. Cool, transfer to a100ml graduated flask and dilute to the mark. Transfer by means of a pipette a10ml aliquot (Note2) into a small beaker, ad
31、d1ml of hydroxyammonium chloride solution(10per cent) and heat just to boiling. Cool, add2ml of sodium tartrate solution(20per cent) and one drop of thymol blue indicator, and neutralize with ammonia solution (sp. gr.0.91) to the blue colour. Transfer to a200ml separating funnel, add65ml of potassiu
32、m cyanide solution (ammoniacal) and20.0ml of dithizone solution(0.006per cent), and shake for one minute. Insert a roll of filter paper 1)in the stem of the funnel and run off the chloroform layer into a small stoppered bottle. Measure the optical density of the solution at20 1 C using the condition
33、s specified under “Apparatus”, and using chloroform in the reference cell. Carry out simultaneously a blank determination on the reagents. Follow the same procedure without the sample and use the same quantity of reagents. 1) Whatman No.41 is suitable.BS3338-5:1961 2 BSI 11-1999 Deduct the blank rea
34、ding and calculate the percentage lead in the sample by reference to the appropriate calibration graph. Calibration Transfer to50-ml beakers the following amounts of standard lead solution (1ml N 0.01mg Pb): for the4cm cell0.5,1.0,1.5,2.0ml for the1cm cell2.0,4.0,6.0,8.0ml. Dilute to10ml, add1ml of
35、hydroxyammonium chloride solution(10per cent) and2ml sodium tartrate solution(20per cent) and continue as in the procedure. Carry out simultaneously a blank, using the same quantities of reagents. Prepare calibration graphs by plotting optical density against weight of lead in the various aliquots,
36、after deduction of the blank reading. NOTE 1A4cm cell should be used for lead contents up to0.08per cent and a1cm cell for lead contents up to0.9percent. NOTE 2For lead contents between0.3and0.6per cent a5ml aliquot should be taken, and for lead contents between0.6and1.0per cent a2ml aliquot. All al
37、iquots should be diluted to10ml with water.blankBS3338-5: 1961 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view on standards in Europe and at the international level. It is
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