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1、BRITISH STANDARD BS 3338-19: 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 alloys Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:54:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI
2、 BS 3338-19:1966 This British Standard, having been approved by the Non-ferrous Metals Industry Standards Committee and endorsed by the Chairman of the Engineering Divisional Council, was published under the authority of the General Council on 28 July 1966 BSI 12-1999 The following BSI references re
3、late to the work on this standard: Committee references NFE/27, NFE/27/1 Draft for comment D65/6656 ISBN 0 580 03197 7 Co-operating organizations The Non-ferrous Metals Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the foll
4、owing Government departments and scientific and industrial organizations: Aluminium FederationInstitution of Mining and Metallurgy Association of Bronze and Brass FoundersInstitution of Production Engineers Association of Consulting EngineersInstitution of Structural Engineers Board of TradeLead Dev
5、elopment Association British Bronze and Brass Ingot ManufacturersLight Metal Founders Association AssociationLondon Metal Exchange* British Electrical and Allied ManufacturersMagnesium Industry Council Association*Ministry of Defence, Army Department* British Lead Manufacturers AssociationMinistry o
6、f Defence, Navy Department* British Non-ferrous Metals FederationNational Brassfoundry Association British Non-ferrous Metals ResearchNon-ferrous Metal Stockists Association*Post Office* Copper Development AssociationRoyal Institute of British Architects Crown Agents for Oversea Governments andSocie
7、ty of British Aerospace Companies Ltd. AdministrationsSociety of Motor Manufacturers and Electric Cable Makers ConfederationTraders Ltd.* High Conductivity Copper AssociationTin Research Institute* Institute of British FoundrymenZinc Development Association Institute of MetalsIndividual manufacturer
8、 Institution of Mechanical Engineers (Automobile Division) The Government departments and scientific 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 British Standard
9、: British Railways BoardLondon Transport Board British Tin Box Manufacturers FederationSolder Makers Association Cable Makers AssociationTinplate Conference (1925) Electronic Engineering AssociationTin Producers Association Gas CouncilWhite Metal Bearing Manufacturers Institution of Gas EngineersInd
10、ividual firms Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:54:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3338-19:1966 BSI 12-1999i Contents Page Co-operating organizationsInside front cover Forewordii Introduction1 Apparatus
11、1 Solutions required1 Sampling1 Procedure2 Calibration2 Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:54:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3338-19:1966 ii BSI 12-1999 Foreword This standard makes reference to the following British Standards: BS 219, Soft solders. BS 3252,
12、Ingot tin. BS 3332, White metal bearing alloy ingots. BS 3338, Methods for the sampling and analysis of tin and tin alloys Part 12: 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 ni
13、neteenth 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 methods has been authorized by the Non-Ferrous Metal
14、s 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: Part 1: Sampling of ingot tin; Part 2: Determination of tin in ingot tin; Part 3: Determination of antimon
15、y in ingot tin; 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,
16、 tin-lead solders 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; Par
17、t 13: Determination 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
18、 solders and white metal bearing alloys; Part 18: Determination of aluminium in solders and white metal bearing alloys. The complete British Standard methods will be found suitable for the grades of metals covered by BS 3252, “Ingot tin”, BS 219, “Soft solders”, and BS 3332, “White metal bearing all
19、oy ingots”. In the 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 shou
20、ld be adjusted accordingly. 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. Licensed Copy: sheffieldun sheffieldun,
21、na, Wed Nov 29 07:54:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3338-19:1966 BSI 12-1999iii 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 do
22、es not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i to iv, pages 1 and 2 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated
23、in the amendment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:54:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI iv blank Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:54:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3338-19:1966 BSI 12-1999
24、1 Introduction a) Principle. Zinc is determined photometrically with dithizone after removal of interfering elements. b) Range. Up to 0.015 per cent of zinc. c) Reproducibility. 10 per cent of zinc present. Apparatus a) All volumetric glassware used shall be of Class A accuracy as defined in the app
25、ropriate 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 of 535 m may be used together with 1
26、cm or 4 cm cells. c) Alternatively, where a filter photometer of the balanced two-cell type is used, the following conditions have been found suitable: Tungsten lamp Ilford 604 or equivalent filters 1 or 4 cm cells Solutions required All reagents shall be of the highest purity obtainable and distill
27、ed1) water shall be used throughout. Solutions shall be freshly prepared and, where necessary, filtered. Standard zinc (1 ml N 0.1 mg of zinc). Dissolve 0.100 g of zinc in 50 ml of hydrochloric acid (25 per cent), transfer to a 1 litre volumetric flask and dilute to the mark. Standard zinc (1 ml N 0
28、.005 mg of zinc). Transfer 25.0 ml of standard zinc solution (1 ml N 0.1 mg of zinc) to a 500 ml volumetric flask and dilute to the mark. Standard zinc (1 ml N 0.001 mg of zinc). Transfer 20.0 ml of standard zinc solution (1 ml N 0.005 mg of zinc) to a 100 ml volumetric flask and dilute to the mark.
29、 Acetic acid (50 per cent v/v). Dilute 50 ml of glacial acetic acid to 100 ml. Ammonia (50 per cent v/v). Dilute 50 ml of ammonia solution (sp. gr. 0.91) to 100 ml. Ammonia (2 per cent v/v). Dilute 2 ml of ammonia solution (sp. gr. 0.91) to 100 ml. Bromine-acid mixture. To 45 ml of hydrochloric acid
30、 (sp. gr. 1.16 to 1.18) and 45 ml of hydrochloric acid (sp. gr. 1.46 to 1.49), add carefully 10 ml of bromine. Dithizone solution (0.005 per cent w/v). Dissolve 0.025 g of dithizone in 25 ml of chloroform and shake with 100 ml of ammonia solution (2 per cent) for 1 minute. Separate the two layers an
31、d shake the chloroform layer with a further 100 ml of ammonia solution (2 per cent) for one minute. Discard the chloroform layer, combine the two aqueous layers and wash with 20 ml of carbon tetrachloride. Make the aqueous solution just acid with hydrochloric acid (50 per cent) and shake with 250 ml
32、 of carbon tetrachloride. Separate the carbon tetrachloride layer, add a further 250 ml of carbon tetrachloride and shake again. Separate and combine the carbon tetrachloride extracts, wash them with water and store in a dark bottle. Hydrochloric acid (50 per cent v/v). Dilute 50 ml of hydrochloric
33、acid (sp. gr. 1.16 to 1.18) to 100 ml. Hydrochloric acid (25 per cent v/v). Dilute 25 ml of hydrochloric acid (sp. gr. 1.16 to 1.18) to 100 ml. Hydrochloric acid (10 per cent v/v). Dilute 10 ml of hydrochloric acid (sp. gr. 1.16 to 1.18) to 100 ml. Bis (2-hydroxyethyl) dithicarbamate. Dissolve 4.0 g
34、 of diethanolamine and 1.0 ml of carbon disulphide in 40 ml of methanol. The solution will keep for 3 to 4 days. Nitric acid (50 per cent v/v). Dilute 50 ml of nitric acid (sp. gr. 1.42) to 100 ml. Sodium cyanide (5 per cent w/v). Dissolve 5 g of sodium cyanide in 50 ml of water and dilute to 100 ml
35、. Sodium sulphide (0.04 per cent w/v). Dissolve 0.4 g of sodium sulphide in 50 ml of freshly boiled distilled water and dilute to 1 litre with freshly boiled distilled water. Prepare freshly each day. Sodium tartrate (20 per cent w/v). Dissolve 20 g of sodium tartrate in 70 ml of water and dilute to
36、 100 ml. Methyl red (0.05 per cent w/v). Dissolve 0.05 g of water soluble methyl red in 100 ml of water. Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS 3338, Part 12 “Sampling of solders” and Part 14, “Sampling of white metal
37、bearing alloy ingots”. 1) Water demineralized by ion exchange may be used if it is of equivalent quality. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:54:52 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 3338-19:1966 2 BSI 12-1999 Procedure Weigh 1 g of the sample and transfer to a 150 m
38、l beaker. Add 20 ml of the bromine-acid mixture and 5 ml of perchloric acid (sp. gr. 1.54). Evaporate to fuming and if the solution is cloudy add a further 5 ml of the bromine-acid mixture. Repeat the evaporation until the solution is clear. Cool, add 20 ml of water and 5 ml of hydrochloric acid (50
39、 per cent) and cool again in an ice-sodium chloride mixture. Filter off any lead chloride through a sintered glass filter (porosity 4) and wash with chilled hydrochloric acid (10 per cent). Transfer the filtrate to a 100 ml metric flask and dilute to the mark. Transfer a 25 ml aliquot to a 100 ml be
40、aker and pass hydrogen sulphide gas for 10 to 15 minutes. Filter through a medium texture filter paper2) and wash the precipitate two or three times with hot water. Evaporate the filtrate to less than 20 ml, oxidize with two drops of nitric acid (50 per cent), cool and transfer to a 100 ml separatin
41、g funnel. Dilute to about 25 ml, add 1 drop of methyl red indicator (0.05 per cent), 2 ml of sodium tartrate solution (20 per cent), then ammonia solution (50 per cent), dropwise until the colour changes to yellow. Add 1 ml of sodium cyanide solution (5 per cent), then acetic acid (50 per cent), dro
42、pwise until the neutral peach colour is obtained. Extract the methyl red by shaking the solution with 5 ml of carbon tetrachloride, allow the layers to separate and discard the carbon tetrachloride layer. Add 1 ml of the bis (2-hydroxyethyl) dithicarbamate solution and extract the zinc with dithizon
43、e solution (0.005 per cent) as follows: Shake with 10 ml of dithizone solution (0.005 per cent) for 1 minute. Allow the layers to separate and run the carbon tetrachloride layer into a second separating funnel. Shake the aqueous layer with 5 ml portions of dithizone solution (0.005 per cent), runnin
44、g each successive extract into the second separating funnel until there is no change in the colour of the dithizone solution. To the aqueous layer remaining in the first funnel add 5 ml of carbon tetrachloride, shake, allow to separate and add the carbon tetrachloride layer to the combined extracts.
45、 Discard the aqueous layer. Shake the combined dithizone extracts with 20 ml of sodium sulphide solution (0.04 per cent) for 30 seconds, allow the layers to separate and discard the aqueous layer. Repeat this extraction with further 10 ml portions of sodium sulphide solution (0.04 per cent) until th
46、e upper aqueous layer is colourless. Remove any droplets of water from the stem of the separating funnel by inserting a roll of filter paper2). Remove the paper and run off the carbon tetrachloride layer into a dry 50 ml volumetric flask. Wash the aqueous layer with carbon tetrachloride, allow the l
47、ayers to separate then transfer the carbon tetrachloride layer to the same volumetric flask. Dilute to the mark with carbon tetrachloride. Measure the optical density of the solution at 20 1 C using the conditions specified under “Apparatus”. Carry out simultaneously a blank determination on the rea
48、gents. Follow the same procedure without the sample and use the same quantities of reagents. Deduct the blank reading and calculate the percentage of zinc in the sample by reference to the calibration graph. Calibration Transfer to a series of separating funnels the following amounts of standard zin
49、c solution: For the 1 cm cell 0, 2.0, 4.0, 6.0 and 8.0 ml of standard zinc solution (1 ml N 0.005 mg of zinc). For the 4 cm cell 0, 2.0, 4.0, 6.0, 8.0 and 10 ml of standard zinc solution (1 ml N 0.001 mg of zinc). Continue from Paragraph 4 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. Licensed Copy: sheffieldun sheffieldun, na, Wed Nov 29 07:54:52 GMT+00:00 2006, Uncontrolled Co
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