1、BRITISH STANDARD BS3338-21: 1983 Methods for the sampling and analysis of tin and tin alloys Part21: Determination of high cadmium content of soft solders UDC 669.654:543.24:546.48BS3338-21:1983 This BritishStandard, having been prepared under the directionof the Non-ferrous Metals Standards Committ
2、ee, waspublished under the authorityof the Board of BSI andcomes into effect on 31 October 1983 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference NFE/27 Draft for comment82/76769DC ISBN 0 580 134334 Committees responsible for this BritishStandard The p
3、reparation of this BritishStandard was entrusted by the Non-ferrous Metals Standards Committee (NFE/-) to Technical Committee NFE/27 upon which the following bodies were represented: Association of British Pewter Craftsmen British Steel Industry Electric Cable Makers Confederation Electronic Enginee
4、ring Association Federation of Wire Rope Manufacturers of Great Britain International Tin Research Institute London Metal Exchange Metal Packaging Manufacturers Association National Coal Board Solder Makers Association Coopted members The following bodies were also represented in the drafting of the
5、 standard, through subcommittees and panels: British Association for Brazing and Soldering BNF Metals Technology Centre British Telecom Ministry of Defence Telecommunication Engineering and Manufacturing Association (TEMA) Amendments issued since publication Amd. No. Date of issue CommentsBS3338-21:
6、1983 BSI 12-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Reagents 1 3 Apparatus 1 4 Sampling 1 5 Analysis procedure 1 6 Standardization of EDTA 2 Publications referred to Inside back coverBS3338-21:1983 ii BSI 12-1999 Foreword This Part of this BritishStanda
7、rd has been prepared under the direction of the Non-ferrous Metals Standards Committee. It is an additional Part of a series describing methods for the sampling and analysis of tin and tin alloys. Other Parts of the series are as follows: Part 1: Sampling of ingot tin; Part 2: Determination of tin i
8、n ingot tin (aluminium reduction method); Part 3: Determination of antimony in ingot tin (photometric method); Part 4: Determination of copper in ingot tin and tin-lead solders (photometric method); Part 5: Determination of lead in ingot tin and tin-antimony solders (photometric method); Part 6: Det
9、ermination of copper in high purity ingot tin (photometricmethod); Part 7: Determination of silver in solders (volumetric: ammonium thiocyanate method); Part 8: Determination of bismuth in ingot tin, tin-lead solders and white metal bearing alloys (photometric method); Part 9: Determination of arsen
10、ic in ingot tin, solders and white metal bearing alloys (photometric method); Part 10: Determination of iron in ingot tin, tin-lead solders and white metal bearing alloys (photometric method); Part 11: Determination of tin in solders (nickel coil reduction method); Part 12: Sampling of solders; Part
11、 13: Determination of antimony in solders and white metal bearing alloys (volumetric: potassium bromate method); Part 14: Sampling of white metal bearing alloy ingots; Part 15: Determination of copper and lead in white metal bearing alloys (electrodeposition method); Part 16: Determination of tin in
12、 white metal bearing alloys (nickel coil reduction method); Part 17: Determination of cadmium in solders and white metal bearing alloys (photometric method); Part 18: Determination of aluminium in solders and white metal bearing alloys (photometric method); Part 19: Determination of zinc in solders
13、and white metal bearing alloys (photometric method); Part 20: Determination of nickel in capping metal (photometric method). The complete series is judged suitable for the analysis of tin and tin-base alloys covered by BS219, BS3252, BS3332 and BS5140. In the methods for determining impurities, samp
14、le masses 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. While it is appreciated that other convenient and rapid methods are more than adequate for normal routine commercial requirements, all
15、the methods described have been found to give reliable and reproducible results and are therefore intended primarily as referee procedures to be used in cases of dispute.BS3338-21:1983 BSI 12-1999 iii A British Standard does not purport to include all the necessary provisions of a contract. Users of
16、 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 to iv, pages1and 2, an inside back cover and a back co
17、ver. 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 blankBS3338-21:1983 BSI 12-1999 1 1 Scope This Part of this BritishStandard describes a method for the determination of cadmiu
18、m in tin base soft solder alloys containing10% to30% of cadmium and with reproducibility of0.15% of the cadmium present. NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 2 Reagents During the analysis use only reagents of the highest purity obtaina
19、ble, and of analytical reagent quality. Use water complying with BS3978 throughout and solutions which are freshly prepared and, where necessary, filtered. 2.1 Ammonia solution. Dilute50mL of ammonia solution, approximately0.88g/mL, to100mL with water. 2.2 Bromine-hydrobromic acid solution. Carefull
20、y add10mL bromine to90mL of hydrobromic acid, 1.46g/mL to1.49g/mL. 2.3 Buffer solution. Dissolve54g of ammonium chloride in650mL water and add350mL ammonia solution, approximately0.88g/mL. 2.4 Ethylenediamine tetra-acetic acid solution (EDTA) (0.05mol/L). Dissolve18.61g of the disodium salt of EDTA
21、in1L of water and standardize against cadmium as described in clause6. 2.5 Eriochrome black T solution (EBT) (0.5% m/V). Dissolve0.5g of EBT and4.5g of hydroxylamine hydrochloride in90mL of water containing10mL triethanolamine. 2.6 Nitric acid solution (approximately7 mol/L). Dilute50mL of nitric ac
22、id solution, approximately1.42g/mL, to100mL with water. 2.7 Nitric acid solution (approximately 0.3mol/L). Dilute20mL of nitric acid, approximately 1.42g/mL, to1L with water. 2.8 Sulphuric acid solution (approximately9mol/L). Carefully add50mL of sulphuric acid, approximately 1.84g/mL, to55mL of wat
23、er, mixing and cooling if necessary. 2.9 Sulphuric acid solution (approximately 0.02mol/L). Dilute2mL of sulphuric acid solution(2.8) to1L with water. 2.10 Hydrochloric acid (approximately 2mol/L). Dilute180mL of hydrochloric acid, approximately1.18,to1L with water. 2.11 Hydrochloric acid (approxima
24、tely 0.6mol/L). Dilute50mL of hydrochloric acid, approximately1.18, to1L with water. 3 Apparatus 3.1 All glassware used for volumetric measurement of solutions shall be of class A accuracy as described in BS700-1, BS846, BS1583 and BS1792. 3.2 A cation exchange column shall be constructed of glass t
25、ube16mm internal diameter and approximately400mm long, and fitted with a tap. It shall be filled to a depth of350mm with cation resin 1)prepared in the following manner. Stir approximately50g of the resin with the hydrochloric acid(2.10) and then allow it to settle. Decant the fine particles and fil
26、l the column to the required depth. Elute the column with400mL of distilled or demineralized water at the rate of3mL/min to4mL/min. 4 Sampling The sample for analysis shall be taken by one of the suitable procedures described in BS3338-12. 5 Analysis procedure 5.1 Weigh accurately0.6g of the sample
27、and transfer to a250mL conical beaker. Add20mL of the bromine-hydrobromic acid solution(2.2) and evaporate to dryness, cool and add a further10mL of the bromine-hydrobromic acid solution and evaporate to dryness again. Cool, add10mL of the nitric acid solution(2.6) and10mL of water, and heat to diss
28、olve the salts. Cool, add2mL of the sulphuric acid solution(2.8) evaporate to fumes and heat strongly. Cool, add50mL of water, boil and allow to stand at room temperature for a minimum period of1h. 5.2 Filter, either through a sintered glass crucible of porosity No.4 (see BS1752), or through a suita
29、ble filter paper 2)and wash with the sulphuric acid solution(2.9). 5.3 Pass the filtrate through the cation exchange column and wash with150mL of water, discarding the effluent. Elute the cadmium by passing700mL of the hydrochloric acid(2.11) through the resin. When the first50mL of eluate has been
30、collected, stop the flow for15min and then continue the elution at the rate of3mL/min to4mL/min. 1) Zeolit 225 SRC 14 is known to be suitable. 2) A Whatman No.40 filter paper is known to be suitable.BS3338-21:1983 2 BSI 12-1999 5.4 Evaporate the total eluted solution to dryness, cool, add10mL of the
31、 nitric acid(2.7) and dilute to100mL with water. 5.5 Neutralize the solution with the ammonia solution(2.1) using methyl red as indicator. Add10mL of the buffer solution(2.3) and sufficient EBT solution(2.5) to produce a colour, titrate with EDTA solution(2.4) and note the volume (V 1 ) required to
32、change the indicator colour from red to blue. 5.6 Calculate the value C of the cadmium content of the alloy, as a percentage, from the equation: 6 Standardization of EDTA 6.1 Weigh accurately (in quadruplicate) between0.1g and0.15g of pure cadmium metal into250mL beakers, dissolve in10mL of nitric a
33、cid solution(2.6), evaporate to dryness and add10mL of nitric acid solution(2.7). 6.2 Cool, dilute to100mL with water, and then follow that part of the analysis procedure described in5.5. 6.3 The mean value of the four titrations V 2(in mL) shall be taken as the standard value. 6.4 Calculate the val
34、ue of the factor F from the equation: where V 1 is the titration volume of the EDTA solution (in mL); F is the factor obtained by the procedure described in clause6; M 1 is the mass of sample (in g). C V 1 F M 1 -100 = where M 2 is the mass of cadmium metal used (in g); V 2 is the mean value of the
35、four titrations (in mL). F M 2 V 2 - =BS3338-21:1983 BSI 12-1999 Publications referred to BS 219, Specification for soft solders. BS 700, Graduated pipettes. BS 700-1, Specification for general requirements. BS 846, Specification for burettes. BS 1583, One-mark pipettes. BS 1752, Laboratory sintered
36、 or fritted filters. BS 1792, Specification for one-mark volumetric flasks. BS 3252, Ingot tin. BS 3332, White metal bearing alloy ingots. BS 3338, Methods for the sampling and analysis of tin and tin alloys. BS 3338-12, Sampling of solders. BS 3978, Water for laboratory use. BS 5140, Pewter. BS3338
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