1、BRITISH STANDARD BS3907-12: 1971 Method for The determination of aluminium in magnesium and magnesium alloys (Photometric method) Methods for the analysis of magnesium and magnesium alloysBS3907-12:1971 This BritishStandard, having been approved by the Non-ferrous Metals Industry Standards Committee
2、, was published under the authority ofthe Executive Board on 19March1971 BSI12-1999 The following BSI references relate to the work on this standard: Committee references NFE/23 andNFE/23/4 Draft for comment 70/5245 ISBN 0 580 06178 7 Co-operating organizations The Non-ferrous Metals Industry Standa
3、rds Committee, under whose supervision this BritishStandard was prepared, consists of representatives from the following Government departments and scientific and industrial organizations: Aluminium Federation Association of Bronze and Brass Founders Board of Trade British Bronze and Brass Ingot Man
4、ufacturers Association British Lead Manufacturers Association British Non-ferrous Metals Federation British Non-ferrous Metals Federations High Conductivity Copper Group British Non-ferrous Metals Research Association* Copper Development Association Crown Agents for Oversea Governments and Administr
5、ations Electric Cable Makers Confederation Institute of British Foundrymen Institute of Metals Institution of Mechanical Engineers (Automobile Division) Institution of Mining and Metallurgy Institution of Production Engineers Institution of Structural Engineers Lead Development Association Light Met
6、al Founders Association London Metal Exchange Magnesium Industry Council* Ministry of Defence (Army)* Ministry of Defence (Navy) National Brassfoundry Association Non-ferrous Metal Stockists* Post Office Royal Institute of British Architects Society of Motor Manufacturers and Traders Ltd.* Tin Resea
7、rch Institute Zinc Development Association Individual manufacturers The Government department 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 BritishS
8、tandard: Institute of Sheet Metal Engineering Department of Trade and Industry Department of Trade and Industry Laboratory of the Government Chemist Individual analysts Amendments issued since publication Amd. No. Date CommentsBS3907-12:1971 BSI 12-1999 i Contents Page Co-operating organizations Ins
9、ide front cover Foreword ii 1 Introduction 1 2 Apparatus 1 3 Solutions required 1 4 Sampling 1 5 Procedure 1 6 Calibration 2 7 Calculation 2 8 Notes 2BS3907-12:1971 ii BSI 12-1999 Foreword This standard makes reference to the following BritishStandards: BS1499, Sampling non-ferrous metals. BS3978, W
10、ater for laboratory use. This method for the photometric determination of aluminium in magnesium and magnesium alloys is the twelfth of a series which will form a complete BritishStandard under the collective title “Methods for the analysis of magnesium and magnesium alloys” each being published as
11、a separate part. Other methods in the series are as follows: Part1: Aluminium (gravimetric method); Part2: Iron (photometric 1:10 phenanthroline method); Part3: Copper (photometric method); Part4: Manganese (photometric periodate method); Part5: Manganese (photometric periodate method) (low contents
12、); Part6: Zirconium (photometric method); Part7: Nickel (photometric method); Part8: Total rare earths (gravimetric method); Part9: Zinc (ion-exchange volumetric EDTA method); Part10: Manganese in magnesium alloys containing zirconium, rare earths or thorium (photometric method); Part11: Silicon in
13、magnesium and magnesium alloys. The preparation of this series of methods has been authorized by the Non-ferrous Metals Industry Standards Committee as part of a general programme for the standardization of methods for the sampling and analysis of non-ferrous metals. The methods have been found to g
14、ive reliable and reproducible results and while in some instances they may appear to be lengthy, it should be appreciated that they are primarily intended as “referee” methods to be used in cases of dispute. A British Standard does not purport to include all the necessary provisions of a contract. U
15、sers 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 and 2 and a back cover. This stan
16、dard 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.BS3907-12:1971 BSI 12-1999 1 1 Introduction 1.1 Principle. The sample is dissolved in sulphuric acid, iron and copper are complexed with ascorb
17、ic acid and sodium thiosulphate respectively. Chromazurol S is added to the buffered solution and the determination is completed photometrically. 1.2 Range. The method is recommended for acid soluble aluminium contents between0.005 and0.20%. 1.3 Reproducibility. Experiments have been carried out ind
18、ependently by a number of analysts using this method. The degree of reproducibility that can be expected is shown by the following analysis of the results obtained. 1.4 Application. This method is not suitable for magnesium alloys containing over0.10% of zirconium, and has not been tested on alloys
19、containing rare earths and thorium. 2 Apparatus 2.1 Class A volumetric glassware complying with the appropriate BritishStandards shall be used throughout. 2.2 pH meter fitted with a glass electrode. 2.3 Any instrument suitable for measuring the optical density of the solution at a wavelength of550nm
20、 may be used with a2cm cell. Alternatively, when a filter photometer of the balanced two-cell type is used, the following conditions have been found suitable: Mercury vapour lamp Ilford605 or equivalent filter 2cm cell. 3 Solutions required All reagents shall be of the highest purity obtainable and
21、either distilled or demineralized water complying with BS3978 1)shall be used throughout. Solutions shall be freshly prepared and where necessary filtered. Standard aluminium.(1mlN 0.0125mg of aluminium). Dissolve0.1099g of aluminium potassium sulphate Al 2 (SO 4 ) 3 .K 2 SO 4 .24H 2 O in water. Tra
22、nsfer to a500ml volumetric flask, dilute to the mark and mix. Standard aluminium.(1mlN 0.025mg of aluminium). Dissolve0.2198g of aluminium potassium sulphate Al 2 (SO 4 ) 3 .K 2 SO 4 .24H 2 O in water. Transfer to a500ml volumetric flask, dilute to the mark and mix. Standard aluminium.(1mlN 0.05mg o
23、f aluminium). Dissolve0.4396g of aluminium potassium sulphate Al 2 (SO 4 ) 3 .K 2 SO 4 .24H 2 O in water. Transfer to a500ml volumetric flask, dilute to the mark and mix. Ascorbic acid.(1% w/v). Dissolve1.0g of ascorbic acid in water, dilute to100ml and mix. Chromazurol S. (0.01% w/v). Dissolve0.1g
24、of chromazurol S in methanol-water(50%) and dilute to1litre with methanol-water(50%). Methanol-water (50%). Dilute500ml of methanol to1litre and mix. Sodium acetate sodium thiosulphate. Dissolve150g of sodium acetate (CH 3 .COONa.3H 2 O) and5g of sodium thiosulphate (Na 2 S 2 O 3 .5H 2 O) in water,
25、filter if necessary, dilute to1litre and mix. Sulphuric acid.(25% v/v). To400ml of water add cautiously250ml of sulphuric acid (sp. gr.1.84). Mix, cool, dilute to1litre and mix. 4 Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS
26、1499 “Sampling non-ferrous metals”. 5 Procedure 5.1 Weigh0.5 0.001g of sample, transfer to a250ml beaker, add20ml (Note8.1) of water, then add10ml of sulphuric acid(25%). When the reaction has ceased, heat to boiling and cool. 5.2 Carry out simultaneously a blank determination following the same pro
27、cedure but using5ml of sulphuric acid(25%) instead of10ml. 5.3 Transfer the solution, filtering if necessary, to a250ml volumetric flask, dilute to the mark and mix. Aluminium content Standard deviation % 0.08 0.11 0.0024 0.0056 1) BS3978, “Water for laboratory use”.BS3907-12:1971 2 BSI 12-1999 5.4
28、Transfer the appropriate aliquot shown below to a100ml volumetric flask. 5.5 Add5ml of ascorbic acid(1%) then the appropriate volume of the sodium acetate sodium thiosulphate solution shown in the table above and20ml of chromazurol S solution(0.01%). Dilute to the mark and mix (Note8.2). 5.6 Allow t
29、o stand for30minutes (Note8.3), then measure the optical density using the conditions specified under Apparatus. 6 Calibration 6.1 For aluminium contents between0.005 and0.05% 6.1.1 To each of a series of six250ml volumetric flasks transfer5ml of sulphuric acid(25%) then add: 02.05.010.015.0 and20.0
30、ml of standard aluminium solution (1mlN 0.0125mg of aluminium) equivalent to: 0.00.0050.01250.0250.0375 and0.05% of aluminium. Dilute to the mark and mix. 6.1.2 Transfer20ml to a100ml volumetric flask. Continue from Sub-clause5.5 of the procedure. 6.1.3 Deduct the optical density for the solution co
31、ntaining no added aluminium from the gross optical densities and prepare a calibration graph by plotting the net values against nominal aluminium contents of the solutions. 6.2 For aluminium contents between0.025 and0.10% 6.2.1 To each of a series of five250ml volumetric flasks, transfer5ml of sulph
32、uric acid(25%) then add: 05.010.015.0 and20.0ml of standard aluminium solution (1mlN 0.025mg of aluminium) equivalent to: 00.0250.050.075 and0.100% of aluminium. Dilute to the mark and mix. 6.2.2 Transfer10ml to a100ml volumetric flask. Continue from Subclause5.5 of the procedure. 6.2.3 Deduct the o
33、ptical density for the solution containing no added aluminium from the gross optical densities and prepare a calibration graph by plotting the net values against nominal aluminium contents of the solutions. 6.3 For aluminium contents between0.05 and0.20% 6.3.1 To each of a series of five250ml volume
34、tric flasks, transfer5ml of sulphuric acid(25%) then add: 05.010.015.0 and20.0ml of standard aluminium solution(1mlN 0.05mg of aluminium). equivalent to: 00.050.100.15 and0.20% of aluminium. Dilute to the mark and mix. 6.3.2 Transfer5ml to a100ml volumetric flask. Continue from Sub-clause5.5 of the
35、procedure. 6.3.3 Deduct the optical density for the solution containing no added aluminium from the gross optical densities and prepare a calibration graph by plotting the net values against nominal aluminium contents of the solutions. 7 Calculation Convert the optical densities for the test sample
36、corrected for blank to percentage aluminium by means of the appropriate calibration graph. 8 Notes 8.1 It is recommended that this and all subsequent reagent additions be made by means of a pipette (safety pipette when appropriate) or burette. 8.2 It is essential that the procedure be followed exact
37、ly in order to obtain a pH between5.3 and5.5. 8.3 The calibration and determination should be carried out at the same time and the period of standing for each solution should be taken from the addition of the chromazurol S solution. Aluminium content Aliquot Sodium acetate sodium thiosulphate soluti
38、on % ml ml 0.0050.05 20 20 0.0250.10 10 10 0.050.20 5 5blankBS3907-12: 1971 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 international
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