1、BRITISH STANDARD BS3338-19: 1966 Method for The determination of zinc in solders and white metal bearing alloys (Photometric method) Methods for the sampling and analysis of tin and tin alloysBS3338-19:1966 This BritishStandard, having been approved by the Non-ferrous Metals Industry Standards Commi
2、ttee and endorsed by the Chairman of theEngineering Divisional Council, was published undertheauthority of the GeneralCouncil on 28July1966 BSI12-1999 The following BSI references relate to the work on this standard: Committee references NFE/27, NFE/27/1 Draft for comment D65/6656 ISBN 0 580 03197 7
3、 Co-operating 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: Aluminium Federation Institution of Mining an
4、d Metallurgy Association of Bronze and Brass Founders Institution of Production Engineers Association of Consulting Engineers Institution of Structural Engineers Board of Trade Lead Development Association British Bronze and Brass Ingot Manufacturers Light Metal Founders Association Association Lond
5、on Metal Exchange* British Electrical and Allied Manufacturers Magnesium Industry Council Association* Ministry of Defence, Army Department* British Lead Manufacturers Association Ministry of Defence, Navy Department* British Non-ferrous Metals Federation National Brassfoundry Association British No
6、n-ferrous Metals Research Non-ferrous Metal Stockists Association* Post Office* Copper Development Association Royal Institute of British Architects Crown Agents for Oversea Governments and Society of British Aerospace Companies Ltd. Administrations Society of Motor Manufacturers and Electric Cable
7、Makers Confederation TradersLtd.* High Conductivity Copper Association Tin Research Institute* Institute of British Foundrymen Zinc Development Association Institute of Metals Individual manufacturer Institution of Mechanical Engineers (Automobile Division) The Government departments and scientific
8、and industrial 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 Board London Transport Board British Tin Box Manufacturers Federation Solder Makers
9、 Association Cable Makers Association Tinplate Conference (1925) Electronic Engineering Association Tin Producers Association Gas Council White Metal Bearing Manufacturers Institution of Gas Engineers Individual firms Amendments issued since publication Amd. No. Date CommentsBS3338-19:1966 BSI 12-19
10、99 i Contents Page Co-operating organizations Inside front cover Foreword ii Introduction 1 Apparatus 1 Solutions required 1 Sampling 1 Procedure 2 Calibration 2BS3338-19:1966 ii BSI 12-1999 Foreword This standard makes reference to the following BritishStandards: BS219, Soft solders. BS3252, Ingot
11、tin. BS3332, White metal bearing alloy ingots. BS3338, Methods for the sampling and analysis of tin and tin alloys Part12:Sampling of solders Part 14:Sampling of white metal bearing alloy ingots. This method for the determination of zinc in solders and white metal bearing alloys is the nineteenth of
12、 a series of methods which will form a complete BritishStandard 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 methods has been authorized by the Non-Ferrous Metals Industry S
13、tandards 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: Part 1: Sampling of ingot tin; Part 2: Determination of tin in ingot tin; Part 3: Determination of antimony in ingot t
14、in; Part 4: Determination of copper in ingot tin and tin-lead solders; Part 5: Determination of lead in ingot tin and tin-antimony solders; Part 6: Determination of copper in high purity ingot tin; Part 7: Determination of silver in solders; Part 8: Determination of bismuth in ingot tin, tin-lead so
15、lders and white metal bearing alloys; Part 9: Determination of arsenic in tin, solders and white metal bearing alloys; Part 10: Determination of iron in ingot tin, tin-lead solders and white metal bearing alloys; Part 11: Determination of tin in solders; Part 12: Sampling of solders; Part 13: Determ
16、ination of antimony in solders and white metal bearing alloys; Part 14: Sampling of white metal bearing alloy ingots; Part 15: Determination of copper and lead in white metal bearing alloys; Part 16: Determination of tin in white metal bearing alloys; Part 17: Determination of cadmium in solders and
17、 white metal bearing alloys; Part 18: Determination of aluminium in solders and white metal bearing alloys. 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 t
18、he methods for 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 or aliquots should be adjusted a
19、ccordingly. 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.BS3338-19:1966 BSI 12-1999 iii A British Standard does no
20、t 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 inside f
21、ront cover, pagesi to iv, pages1and 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.iv blankBS3338-19:1966 BSI 12-1999 1 Introduction a) Principle. Zinc is determ
22、ined photometrically with dithizone after removal of interfering elements. b) Range. Up to0.015percent of zinc. c) Reproducibility. 10percent of zinc present. Apparatus a) All volumetric glassware used shall be of Class A accuracy as defined in the appropriate BritishStandards, or where no BritishSt
23、andard 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 of535m may be used together with1cm or4cm cells. c) Alternatively, where a filter photo
24、meter of the balanced two-cell type is used, the following conditions have been found suitable: Tungsten lamp Ilford604 or equivalent filters 1or4cm cells Solutions required All reagents shall be of the highest purity obtainable and distilled 1)water shall be used throughout. Solutions shall be fres
25、hly prepared and, where necessary, filtered. Standard zinc (1mlN 0.1mg of zinc). Dissolve0.100g of zinc in50ml of hydrochloric acid(25percent), transfer to a1litre volumetric flask and dilute to the mark. Standard zinc (1mlN 0.005mg of zinc). Transfer25.0ml of standard zinc solution(1mlN 0.1mg of zi
26、nc) to a500ml volumetric flask and dilute to the mark. Standard zinc (1mlN 0.001mg of zinc). Transfer20.0ml of standard zinc solution(1mlN 0.005mg of zinc) to a100ml volumetric flask and dilute to the mark. Acetic acid (50percentv/v). Dilute50ml of glacial acetic acid to100ml. Ammonia (50percentv/v)
27、. Dilute50ml of ammonia solution (sp.gr.0.91) to100ml. Ammonia (2percentv/v). Dilute2ml of ammonia solution (sp.gr.0.91) to100ml. Bromine-acid mixture. To45ml of hydrochloric acid (sp.gr.1.16 to1.18) and45ml of hydrochloric acid (sp.gr.1.46 to1.49), add carefully10ml of bromine. Dithizone solution (
28、0.005percentw/v). Dissolve0.025g of dithizone in25ml of chloroform and shake with100ml of ammonia solution(2percent) for1minute. Separate the two layers and shake the chloroform layer with a further100ml of ammonia solution (2percent) for one minute. Discard the chloroform layer, combine the two aqu
29、eous layers and wash with20ml of carbon tetrachloride. Make the aqueous solution just acid with hydrochloric acid(50percent) and shake with250ml of carbon tetrachloride. Separate the carbon tetrachloride layer, add a further250ml of carbon tetrachloride and shake again. Separate and combine the carb
30、on tetrachloride extracts, wash them with water and store in a dark bottle. Hydrochloric acid (50percentv/v). Dilute50ml of hydrochloric acid (sp.gr.1.16 to1.18) to100ml. Hydrochloric acid (25percentv/v). Dilute25ml of hydrochloric acid (sp.gr.1.16 to1.18) to100ml. Hydrochloric acid (10percentv/v).
31、Dilute10ml of hydrochloric acid (sp.gr.1.16 to1.18) to100ml. Bis (2-hydroxyethyl) dithicarbamate. Dissolve4.0g of diethanolamine and1.0ml of carbon disulphide in40ml of methanol. The solution will keep for3 to4days. Nitric acid (50percentv/v). Dilute50ml of nitric acid (sp.gr.1.42) to100ml. Sodium c
32、yanide (5percentw/v). Dissolve5g of sodium cyanide in50ml of water and dilute to100ml. Sodium sulphide (0.04percentw/v). Dissolve0.4g of sodium sulphide in50ml of freshly boiled distilled water and dilute to1litre with freshly boiled distilled water. Prepare freshly each day. Sodium tartrate (20perc
33、entw/v). Dissolve20g of sodium tartrate in70ml of water and dilute to100ml. Methyl red (0.05percentw/v). Dissolve0.05g of water soluble methyl red in100ml of water. Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS3338, Part 12 “
34、Sampling of solders” and Part 14, “Sampling of white metal bearing alloy ingots”. 1) Water demineralized by ion exchange may be used if it is of equivalent quality.BS3338-19:1966 2 BSI 12-1999 Procedure Weigh1g of the sample and transfer to a150ml beaker. Add20ml of the bromine-acid mixture and5ml o
35、f perchloric acid (sp.gr.1.54). Evaporate to fuming and if the solution is cloudy add a further5ml of the bromine-acid mixture. Repeat the evaporation until the solution is clear. Cool, add20ml of water and5ml of hydrochloric acid (50percent) and cool again in an ice-sodium chloride mixture. Filter
36、off any lead chloride through a sintered glass filter (porosity4) and wash with chilled hydrochloric acid (10percent). Transfer the filtrate to a100ml metric flask and dilute to the mark. Transfer a25ml aliquot to a100ml beaker and pass hydrogen sulphide gas for10 to15minutes. Filter through a mediu
37、m texture filter paper 2)and wash the precipitate two or three times with hot water. Evaporate the filtrate to less than20ml, oxidize with two drops of nitric acid (50percent), cool and transfer to a100ml separating funnel. Dilute to about25ml, add1 drop of methyl red indicator (0.05percent),2ml of
38、sodium tartrate solution (20percent), then ammonia solution(50percent), dropwise until the colour changes to yellow. Add1ml of sodium cyanide solution(5percent), then acetic acid (50percent), dropwise until the neutral peach colour is obtained. Extract the methyl red by shaking the solution with5ml
39、of carbon tetrachloride, allow the layers to separate and discard the carbon tetrachloride layer. Add1ml of the bis (2-hydroxyethyl) dithicarbamate solution and extract the zinc with dithizone solution(0.005percent) as follows: Shake with10ml of dithizone solution(0.005percent) for1minute. Allow the
40、 layers to separate and run the carbon tetrachloride layer into a second separating funnel. Shake the aqueous layer with5ml portions of dithizone solution (0.005percent), running each successive extract into the second separating funnel until there is no change in the colour of the dithizone solutio
41、n. To the aqueous layer remaining in the first funnel add5ml of carbon tetrachloride, shake, allow to separate and add the carbon tetrachloride layer to the combined extracts. Discard the aqueous layer. Shake the combined dithizone extracts with20ml of sodium sulphide solution(0.04percent) for30seco
42、nds, allow the layers to separate and discard the aqueous layer. Repeat this extraction with further10ml portions of sodium sulphide solution (0.04percent) until the upper aqueous layer is colourless. Remove any droplets of water from the stem of the separating funnel by inserting a roll of filter p
43、aper 2) . Remove the paper and run off the carbon tetrachloride layer into a dry50ml volumetric flask. Wash the aqueous layer with carbon tetrachloride, allow the layers to separate then transfer the carbon tetrachloride layer to the same volumetric flask. Dilute to the mark with carbon tetrachlorid
44、e. Measure the optical density of the solution at20 1 C using the conditions specified under “Apparatus”. Carry out simultaneously a blank determination on the reagents. Follow the same procedure without the sample and use the same quantities of reagents. Deduct the blank reading and calculate the p
45、ercentage of zinc in the sample by reference to the calibration graph. Calibration Transfer to a series of separating funnels the following amounts of standard zinc solution: For the1cm cell0,2.0,4.0,6.0 and8.0ml of standard zinc solution (1mlN 0.005mg of zinc). For the4cm cell0,2.0,4.0,6.0,8.0 and1
46、0ml of standard zinc solution (1mlN 0.001mg of zinc). Continue from Paragraph4 of the procedure. Prepare calibration graphs by plotting optical densities against the weight of zinc in the various aliquots, after deduction of the blank reading. 2) Whatman No.40 is suitable.blankBS3338-19: 1966 BSI 38
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