1、BRITISH STANDARD BS 1728-5: 1953 Incorporating Amendment No. 1 Method for The determination of copper in aluminium and aluminium alloys (Absorptiometric method) Methods for the analysis of aluminium and aluminium alloysBS1728-5:1953 This British Standard, having been approved by the Non-ferrousMetal
2、s Industry Standards Committee and endorsed by the Chairman oftheEngineering DivisionalCouncil, was publishedunder theauthorityofthe GeneralCouncil on 16October1953 BSI 12-1999 ISBN 0 580 01998 5 Co-operating organizations The Non-ferrous Metals Industry Standards Committee, under whose supervision
3、this British Standard was prepared, consists of representatives from the following Government departments, and scientific and industrial organizations: Admiralty* Aluminium Development Association Association of Bronze and Brass Founders Association of Consulting Engineers, Incorporated Association
4、of Non-ferrous Metal Stockists Brass and Copper Tube Association Brass Wire Association British Bronze and Brass Ingot Manufacturers Association British Electrical and Allied Manufacturers Association British Non-ferrous Metals Research Association* Cable Makers Association Cold Rolled Brass and Cop
5、per Association Copper Development Association Crown Agents for the Colonies General Post Office High Commission of India High Conductivity Copper Association Institute of British Foundrymen Institute of Metals Institution of Mechanical Engineers (Automobile Division) Institution of Mining and Metal
6、lurgy Institution of Structural Engineers Lead Sheet and Pipe Manufacturers Federation Light Metal Founders Association* London Metal Exchange Manufactured Copper Association Ministry of Supply* National Brassfoundry Association Nickel Silver Association Royal Institute of British Architects Sheet M
7、akers Conference Society of British Aircraft Constructors Tin Research Institute Wrought Light Alloys Association Zinc Development Association Individual manufacturers* The Government departments and scientific and industrial organizations marked with an asterisk in the above list, together with the
8、 following, were directly represented on the sub-committee entrusted with the preparation of this British Standard: ALAR (Association of Light Alloy Refiners) Aluminium Industry Council Department of the Government Chemist Individual analysts Amendments issued since publication Amd. No. Date of issu
9、e Comments 5267 June 1964 Indicated by a sideline in the marginBS1728-5:1953 BSI 12-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii Introduction 1 Special apparatus 1 Reagents required 1 Sampling 2 Procedure 2BS1728-5:1953 ii BSI 12-1999 Foreword This standard makes re
10、ference to the following British Standards: BS 1490, Aluminium and aluminium alloy ingots and castings for general engineering purposes. BS 1499, Sampling non-ferrous metals. This method for the determination of small amounts of copper is the fifth of a series of methods for the analysis of aluminiu
11、m and aluminium alloys and is intended for use with alloys containing smaller percentages of copper than those covered by BS1728-1. The series will form a complete British Standard, each method being published as a separate part. Other methods in this series are as follows: Part 1: Copper; Part 2: M
12、agnesium; Part 3: Zinc (mercuric potassium thiocyanate method); Part 4: Zinc (polarographic method). 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
13、of non-ferrous metals. The methods given have been found to give reliable and reproducible results and, while in some instances the methods 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 purpo
14、rt 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 front co
15、ver, pages i and ii, pages1 to 3 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.BS1728-5:1953 BSI 12-1999 1 Introduction a) Principle. The metal is treated with mi
16、xed acids and the silicon removed by fuming and subsequent filtration. Copper is recovered from the residue by treatment with hydrofluoric and nitric acids and is added to the filtrate. Copper is separated by precipitation as sulphide, dissolved, and determined photometrically at about436m as the di
17、ethyldithiocarbamate complex in carbon tetrachloride solution. The method is applicable to alloys containing even substantial amounts of antimony, bismuth, cadmium, lead, nickel and tin. b) Range. The method is suitable for copper contents between0.01and 0.5per cent. c) Reproducibility. Experiments
18、have been carried out by a number of independent analysts using the method recommended in this standard. The degree of reproducibility that can be expected is shown by the following analysis of the results obtained: Special apparatus a) A satisfactory instrument for this method is the Hilger photoel
19、ectric absorptiometer. Suitable sets of conditions for the determination of copper by means of this instrument are given under “Procedure” (page 2). Other instruments of similar type may be used, but modifications of operational details may be required. b) Any volumetric glassware used shall be of C
20、lass 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 All reagents shall be of recognized analytical quality and distilled water
21、 shall be used throughout. Solutions shall be freshly prepared and, where necessary, filtered. Ammonium hydroxide (sp. gr. 0.880). Aqua regia (1:1). Add25ml. of nitric acid (sp.gr.1.42) and75ml. of hydrochloric acid (sp. gr.1.16) to100ml. of water. Citric acid (30per cent). Dissolve300g. of citric a
22、cid in water and dilute to1000 ml. Hydrochloric acid (sp. gr. 1.16). Hydrofluoric acid (40per cent). Nitric acid (sp. gr. 1.42). Nitric acid (1:1). Mix500ml. of nitric acid (sp. gr.1.42) with500ml. of water. Sulphuric acid (1:1). Add500ml. of sulphuric acid (sp. gr.1.84) cautiously to500ml. of water
23、 and cool. Sulphuric acid (1 per cent). Add5ml. of sulphuric acid (sp. gr.1.84) to500ml. of water. Alloy Copper found (mean) per cent Standard deviation Special alloy A 0.0118 0.0017 LM5 (to BS 1490) 0.0338 0.0024 LM6 (to BS 1490) 0.114 0.0054 Special alloy B 0.323 0.019 Mixed acids. Hydrochloric ac
24、id (sp. gr. 1.16) 75 ml. Nitric acid (sp. gr. 1.42) 75 ml. Sulphuric acid (sp. gr. 1.84) 150 ml. Distilled water 700 ml. Add the sulphuric acid cautiously to the water. Cool and add the hydrochloric and nitric acids.BS1728-5:1953 2 BSI 12-1999 Sodium diethyldithiocarbamate solution (0.1 per cent). D
25、issolve0.5g. of sodium diethyldithiocarbamate in500ml. of cold water. Filter before use. Standard copper solution. Dissolve1g. of electrolytic copper in10ml. of nitric acid (1:1), evaporate nearly to dryness and dilute to1000ml. in a graduated flask. Pipette10.0ml. from this stock solution and dilut
26、e to1000ml. 1 ml. = 0.00001 g. copper. Hydrogen sulphide wash solution. Saturate sulphuric acid (1per cent) with hydrogen sulphide. Carbon tetrachloride. Sodium sulphate (anhydrous). Electrolytic copper. Hydrogen sulphide gas. Pass through a wash-bottle containing water. Sampling Recommended methods
27、 of obtaining a suitable sample for the analytical procedure given below are described in BS1499, “Sampling non-ferrous metals”. Procedure To 2.0 g. of the sample in a450ml. shallow beaker add10ml. of the mixed acids and, after the reaction has subsided, add a further60ml. Add 20ml. of sulphuric aci
28、d (1:1), evaporate the solution to fumes and continue the fuming for10minutes. Cool, dilute to200ml. and boil until the soluble salts are dissolved. Filter off the insoluble matter on a paper-pulp pad and wash with hot sulphuric acid (1per cent). Reserve the filtrate. Ignite the insoluble matter in
29、a silica basin at a temperature not exceeding 600 C. Brush the residue into a platinum basin. Treat with1ml. of sulphuric acid (1:1) and a few millilitres of hydrofluoric acid(40percent). Add nitric acid (1:1), drop by drop as the reaction may be violent, until the silicon is dissolved. Evaporate to
30、 fumes of sulphuric anhydride, cool, dissolve in a few millilitres of water and add to the reserved filtrate. Adjust the volume to300ml., heat the solution to60 C., add a small quantity of ashless paper pulp (e.g.half a Whatman accelerator weighing about150mg.) and pass hydrogen sulphide through rap
31、idly for at least20minutes. Warm to coagulate the precipitate, filter off the copper sulphide on a hardened, medium-textured paper (Whatman No.540is suitable) and wash with warm hydrogen sulphide wash solution. Place the funnel and filter paper over the beaker used for precipitation, extract the pre
32、cipitate with sufficient hot aqua regia (1:1) (20to25ml.) and then wash with hot water. Dry and ignite the filter paper and residue at a temperature not exceeding600 C. in a porcelain or silica crucible. Dissolve the residue in the crucible in23ml. of nitric acid (1:1) and add to the main solution.
33、Evaporate the solution to small volume, add10ml. of hydrochloric acid (sp. gr.1.16) and evaporate to dryness. Add5ml. of nitric acid(1:1) dilute with10ml. water, digest and cool. Filter through an open-textured paper into a200ml. graduated flask, wash the paper with cold water, dilute to the mark an
34、d mix well. Into a250ml. separating funnel, pipette a suitable aliquot, according to the copper content of the sample as follows: Add5ml. of citric acid solution (30per cent) and10ml. of ammonium hydroxide (sp. gr.0.880), mixing well. Dilute to approximately80ml. with water, add10ml. of sodium dieth
35、yldithiocarbamate solution(0.1per cent), mix well and allow to stand for15minutes. Copper content (per cent) Aliquot (ml.) 0.010.05 50 0.050.10 25 0.100.25 10 0.250.50 5BS1728-5:1953 BSI 12-1999 3 Avoiding strong light (see Note1) extract successively with25ml.,15ml. and10ml. of carbon tetrachloride
36、, shaking for one minute in each case. Filter the successive extracts through a dry9cm. open-textured filter paper (Whatman No.541is suitable) into a50ml. graduated flask and make up to the mark. Add0.5g. of anhydrous sodium sulphate, shake and allow to settle. Carry out a “blank” determination thro
37、ughout the whole procedure, using the same aliquots as in the test. Measure the extinction of the test and “blank” solutions on the photoelectric absorptiometer without delay (see Note1) using1cm.,2cm. or4cm. cells, whichever are appropriate, under one of the following sets of conditions: Calibratio
38、n of instrument. Pipette suitable aliquots of standard copper solution (1ml.=0.00001g. copper) into a series of250ml. separating funnels, add the same reagents and in the same quantities as for the test solution above and proceed as before. Prepare a calibration curve by plotting the extinction valu
39、es against the nominal copper contents of the synthetic solutions. NOTE 1In contrast to the behaviour of the aqueous solution the carbon tetrachloride extract of the copper complex is readily bleached by exposure to strong light. The extraction should therefore be carried out in artificial light or
40、weak daylight. NOTE 2The use of carbon tetrachloride eliminates interference due to tin, lead and antimony. Interference due to amounts of cadmium up to1mg. in the final aliquot can be eliminated by the addition of twice the specified amount of sodium diethyldithiocarbamate solution (0.1per cent). B
41、ismuth interferes, giving a colour about1/20th of the intensity of a similar amount of copper when using Ilford601filter. The effect is additive and hence if bismuth is separately determined and a curve of bismuth against extinction is made, a correction can be applied to the apparent copper content
42、. Extra sodium diethyldithiocarbamate reagent should be added when the bismuth content exceeds2mg. in the final aliquot. The effect of bismuth can be reduced to about1/200th by the use of Ilford 603filter (480m) instead of601; for the former a separate calibration graph is necessary. By reading at t
43、he two wavelengths the presence or absence of bismuth can be detected. Lamp Filters Light Heat a. Tungsten filament Chance OB1 Chance ON13 b. Tungsten filament Ilford 601 Chance ON13 c. Mercury vapour Ilford 601 Chance ON13 d. Mercury vapour Wratten 50 Chance ON13 e. Mercury vapour Corning 5113 Chan
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