1、BRITISH STANDARD BS1728-1: 1951 Incorporating amendment issued June1951 Method for The determination of copper in aluminium and aluminium alloys BS1728-1:1951 This British Standard, having been approved by the Non-ferrousMetals Industry Standards Committee and endorsed by the Chairman of theEngineer
2、ing Divisional Council, was published under theauthority of the General Council on 31 March1951 BSI11-1999 ISBN 0 580 01958 6 Co-operating organizations The Non-ferrous Metals Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from t
3、he following Government departments, and scientific and industrial organizations: Admiralty* Institute of Metals Aluminium Development Association Institute of Mining and Metallurgy Association of Bronze and Brass Founders Institution of Mechanical Engineers Association of Consulting Engineers, (Aut
4、omobile Division) Incorporated Institution of Structural Engineers Association of Non-ferrous Metal Stockists Lead Sheet and Pipe Manufacturers Brass and Copper Tube Association Federation Brass Wire Association Light Metal Founders Association* British Bronze and Brass Ingot Manufacturers London Me
5、tal Exchange Association Manufactured Copper Association British Electrical and Allied Manufacturers Ministry of Supply* Association National Brassfoundry Association British Non-ferrous Metals Research Nickel Silver Association Association* Office of the High Commissioner for India Cable Makers Ass
6、ociation Sheet Makers Conference Cold Rolled Brass and Copper Association Society of British Aircraft Constructors Copper Development Association Tin Research Institute Crown Agents for the Colonies Wrought Light Alloys Association* General Post Office Zinc Development Association High Conductivity
7、Copper Association Individual manufacturers* Institute of British Foundrymen 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 sub-committee entrusted with the preparation of
8、 this British Standard: Department of the Government Chemist ALAR (Association of Light Alloy Refiners) Individual analysts Amendments issued since publication Amd. No. Date CommentsBS1728-1:1951 BSI 11-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii Introduction 1 Spe
9、cial Apparatus 1 Regents Required 1 Sampling 2 Procedure 2 Appendix Statistical analysis of test results 4 BS1728-1:1951 ii BSI 11-1999 Foreword This standard makes reference to the following British Standards: BS604, Graduated measuring cylinders. BS619, Laboratory incubator, water bath and oven th
10、ermometers. BS846-1 and BS846-2, Burettes and bulb burettes. BS1583, One-mark bulb pipettes. BS1704, General purpose thermometers. This method for the determination of copper is the first of a series of methods for the analysis of aluminium and aluminium alloys. The series will form a complete Briti
11、sh Standard, 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 of the standardization of methods for the analysis of non-ferrous metals. The methods have
12、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 provisions of a contr
13、act. 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 to4 and a back cover. This
14、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.BS1728-1:1951 BSI 11-1999 1 Introduction a) Principle. The metal is treated with mixed acids, the silicon removed by fuming and subsequent
15、filtration and the copper in the filtrate precipitated as sulphide. The copper sulphide is ignited and dissolved in acid, and the copper determined iodometrically. Antimony, if present, is separated from the copper sulphide in alkaline sulphide solution. b) Range. The method is suitable for copper c
16、ontents from0.3 per cent upwards. c) Reproducibility. Experiments have been carried out by a number of analysts using the method recommended in this standard, and a statistical analysis of the results, which is given in the Appendix, provides an indication of the degree of reproducibility that can b
17、e expected. Special apparatus Any volumetric glassware used shall be of Class A accuracy, as defined in the appropriate British Standards or, where no British Standard exists, as described in the National Physical Laboratory publication “Volumetric tests on volumetric glassware.” Reagents required A
18、ll reagents shall be of recognized analytical quality, and distilled water shall be used throughout. Solutions shall be freshly prepared and, where necessary, filtered. Hydrochloric-nitric acid mixture (1:1). Mix500ml. hydrochloric acid (sp.gr.1.16) with500ml. nitricacid (sp.gr.1.42). Glacial acetic
19、 acid. Nitric acid (sp.gr. 1.42). Nitric acid (1:1). Mix500ml. of nitric acid (sp.gr.1.42) with500ml. of distilled water. Sulphuric acid (sp.gr. 1.84). Sulphuric acid (1:1). Mix500ml. sulphuric acid (sp.gr.1.84) with500ml. distilled water. Hydrofluoric acid (40per cent). Ammonium hydroxide (sp.gr.0.
20、880). Hydrogen sulphide wash solution. Saturate sulphuric acid(1per cent) with hydrogen sulphide. Potassium iodide solution (50per cent). Dissolve50g. potassium iodide in100ml. of distilled water. Sodium hydroxide solution (20per cent). Dissolve100g. sodium hydroxide in500ml. of distilled water. Sod
21、ium sulphide solution (15per cent). Dissolve15g. sodium sulphide (Na 2 S.9H 2 O) in100ml. of distilled water. Standard sodium thiosulphate solution (0.05N). Dissolve12.41g. sodium thiosulphate in distilled water and make up to1000ml. Stabilize by the addition of2 to3g. borax per litre. Standard sodi
22、um thiosulphate solution (0.02N). Dilute200ml. of standard sodium thiosulphate solution(0.05N) to500ml. with distilled water. Soluble starch solution. Make a paste from1g. of soluble starch and cold distilled water, pour on100ml. of boiling distilled water, boil for a few minutes and cool. This solu
23、tion should be freshly prepared each time. Urea solution (20per cent). Dissolve20g. urea in100ml. of distilled water. Ammonium fluoride. Electrolytic copper. Mixed acids. Hydrochloric acid (sp.gr.1.16) 75ml. Nitric acid (sp.gr.1.42) 75ml. Sulphuric acid (sp.gr.1.84) 150ml. Distilled water 700ml. Add
24、 the sulphuric acid cautiously to the distilled water. Cool, and add the hydrochloric and nitric acids.BS1728-1:1951 2 BSI 11-1999 Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS1499, “Sampling of non-ferrous metals.” Procedure
25、 Method A. In absence of antimony. The quantities of sample, mixed acids and the concentrations of titrating solution vary with the copper content of the metal as follows: Treat the sample in a400ml. beaker with10ml. of the mixed acids and, after the reaction has subsided, with the remainder of the
26、mixed acids, adding a little nitric acid if necessary (see NOTE, page3). Add20ml. of sulphuric acid(1:1), evaporate the solution to fuming and continue fuming for10minutes. Cool, dilute to200ml. and boil until the solution is clear. Filter off the insoluble matter on a paper-pulp pad and wash with h
27、ot water. To recover traces of copper from the residue, ignite the insoluble matter in a platinum crucible. Treat with1ml. of sulphuric acid(1:1) and a few drops of hydrofluoric acid(40per cent). Add nitric acid (sp.gr.1.42), drop by drop, until the silicon is dissolved. Evaporate to fuming, cool, d
28、issolve in a few millilitres of water and add to the filtrate. Heat the solution to60 C., pass hydrogen sulphide rapidly for at least20minutes, warm to coagulate the precipitate, filter off the copper sulphide on a15cm. filter paper (Whatman No.40 or Barcham Green No.803 is suitable) and wash with h
29、ydrogen sulphide wash solution. Dry and ignite the paper and residue at not more than700 C. in a porcelain or silica crucible. Moisten the residue in the crucible with a few drops of water and warm with2 to3ml. of nitric acid (sp.gr.1.42) to dissolve. Transfer to a300ml. conical flask or beaker, boi
30、l nearly to dryness to remove most of the excess nitric acids and re-dissolve in approximately10ml. of water. Add0.1 to0.2g. of ammonium fluoride, neutralize carefully by adding ammonium hydroxide, drop by drop, until the blue cuprammonium compound is formed, and add one drop excess. Acidify with gl
31、acial acetic acid, added drop by drop and add ten drops excess, followed by one drop of urea solution(20per cent). Wash the sides of the flask or beaker, using not more than5ml. of water, add5ml. of potassium iodide solution(50per cent) and titrate with standard sodium thiosulphate solution, adding1
32、ml. of starch solution as indicator towards the end of the titration. Method B. In presence of antimony. The quantities of sample and the concentration of titrating solution vary with the copper content of the metal as follows: Treat the sample in a600ml. beaker with40ml. of hydrochloric-nitric acid
33、 mixture(1:1). When the reaction is complete, dilute slightly and evaporate by boiling until just pasty. Dissolve in a small amount of water and pour into100ml. of sodium hydroxide solution(20per cent) with constant stirring. Dilute to300ml., bring to the boil, add25ml. of sodium sulphide solution(1
34、5per cent), re-boil and allow the precipitate to settle for30minutes. Filter on a paper-pulp pad and wash with hot water containing sodium hydroxide and sodium sulphide solutions(1per cent of each reagent). Copper content (per cent) Weight of sample (grams) Volume of mixed acids (millilitres) Sodium
35、 thiosulphate (normality) 0.3 to2.5 2 70 0.02N 2.5 to5.0 2 70 0.05N 5.0 to15.0 1 35 0.05N Copper content (per cent) Weight of sample (grams) Sodium thiosulphate (normality) 0.3 to2.5 2 0.02N 2.5 to5.0 2 0.05N 5.0 to15.0 1 0.05NBS1728-1:1951 BSI 11-1999 3 Extract the residue with hot nitric acid(1:1)
36、, adding a little sulphurous acid if necessary and wash with hot water. Add5ml. of sulphuric acid (sp.gr.1.84) and evaporate by boiling to low bulk. Dry the paper-pulp pad, from which the bulk of the copper sulphide has been extracted, and ignite for20 to30minutes in a platinum crucible at approxima
37、tely700 C. Dissolve the residue in a few drops of nitric acid (sp.gr.1.42), add a few drops of hydrofluoric acid, if necessary, to dissolve the silicon, combine with the above sulphuric acid solution and evaporate the solution to fuming. Cool, dilute with250ml. of hot water, heat to60 C. and saturat
38、e with hydrogen sulphide. Filter off the copper sulphide on a15cm. filter paper (Whatman No.541 is suitable) and wash with hydrogen sulphide solution. Dry and ignite the paper and the residue as before. Moisten the residue in the crucible with a few drops of water and warm with2 to3ml. of nitric aci
39、d (sp.gr.1.42) to dissolve. Transfer to a300ml. conical flask or beaker, boil nearly to dryness and dissolve in very little water. Proceed as in the last paragraph of Method A to the end of the titration. Standardization of sodium thiosulphate solution. Weigh out exactly1g. of electrolytic copper. D
40、issolve in10ml. nitric acid(1:1), boil nearly to dryness and dilute with water. Cool, and make up the solution to250ml. in a graduated flask. Pipette exactly10ml. (for standardizing0.02N thiosulphate), or25ml. (for standardizing0.05N thiosulphate), add ammonium fluoride, ammonium hydroxide, glacial
41、acetic acid and urea solution as described in Method A above, and titrate with0.02N or0.05N sodium thiosulphate respectively using starch solution as indicator. NOTEIf the silicon content is small (less than2per cent), the recovery of copper from the residue as described in the next paragraph is unn
42、ecessary provided that sufficient hydrofluoric acid is added at this stage to give a clear solution. 1ml.0.02N sodium thiosulphate = 0.001272g. copper. 1ml.0.05N , , = 0.003179g. ,BS1728-1:1951 4 BSI 11-1999 Appendix Statistical analysis of test results Alloy Analyst Copper found (per cent) a D.T.D.
43、683 A B C D E 0.36; 0.36 0.36; 0.34 0.35; 0.35;0.35;0.35;0.35;0.35 0.34; 0.35 0.35; 0.36;0.37 Mean =0.353 Mean 0.36 0.35 0.35 0.35 0.36 Standard deviation = BS1040 (containing0.5 per cent Sb) A B C E F G 2.82; 2.81 2.79; 2.77 2.80; 2.81;2.81;2.80;2.79;2.81 2.79; 2.81;2.79 2.84; 2.83;2.79 2.82; 2.78;
44、2.67 Mean =2.796 Mean 2.82 2.78 2.80 2.80 2.82 2.76 Standard deviation = BS1490 LM-1-M A B C D E 7.37; 7.36 7.40; 7.41 7.41; 7.40;7.41;7.40;7.42;7.38 7.42; 7.40 7.41; 7.42;7.45 Mean =7.404 Mean 7.37 7.41 7.40 7.41 7.43 Standard deviation = a Reference No. of Ministry of Supply specification. Cxx ()
45、2 n 1 -0.008 = Cxx () 2 n 1 -0.035 = Cxx () 2 n 1 -0.022 =blankBS1728-1: 1951 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 internation
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