1、BRITISH STANDARD BS 1728-24: 1976 Methods for The analysis of aluminium and aluminium alloys Part 24: Nickel (atomic absorption method) UDC 669.71:543.422:546.74BS1728-24:1976 This British Standard, having been prepared under the directionof the Non-ferrous Metals Standards Committee, waspublished u
2、nder the authorityof the Executive Boardon 29October1976 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference NFE/-/3 Draft for comment 75/42795 DC ISBN 0 580 09308 5 Cooperating organizations The Non-ferrous Metals Standards Committee, under whose superv
3、ision this British Standard was prepared, consists of representatives from the following Government department and scientific and industrial organizations: Aluminium Federation* Association of Bronze and Brass Founders British Electrical and Allied Manufacturers Association British Lead Manufacturer
4、s Association British Non-ferrous Metals Federation BNF Metals Technology Centre* Copper Development Association Electric Cable Makers Confederation Institute of British Foundrymen Institution of Mechanical Engineers Institution of Mining and Metallurgy Institution of Production Engineers Institutio
5、n of Structural Engineers Lead Development Association Light Metal Founders Association* London Metal Exchange Magnesium Industry Council Ministry of Defence* National Brassfoundry Association Non-ferrous Metal Stockists Royal Institute of British Architects Society of Motor Manufacturers and Trader
6、s Ltd Tin Research Institute Zinc Development Association Individual firm The 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: Association of Light Alloy Refiners
7、Ltd. Department of Industry Laboratory of the Government Chemist Amendments issued since publication Amd. No. Date of issue CommentsBS1728-24:1976 BSI 12-1999 i Contents Page Cooperating organizations Inside front cover Foreword ii Introduction 1 2 Apparatus 1 3 Solutions required 1 4 Sampling 1 5 P
8、rocedure 1 6 Calibration 2 7 Calculation 2 8 Notes 2 Publications referred to Inside back coverBS1728-24:1976 ii BSI 12-1999 Foreword This method for the determination of nickel is the twenty-fourth of a series which will form a complete British Standard under the collective title “Methods for the a
9、nalysis of aluminium and aluminium alloys”, each being published as a separate Part. Other methods in the series are as follows: Part 1: Copper; Part 2: Magnesium; Part 5: Copper (absorptiometric method); Part 6: Iron (volumetric: titanous chloride method); Part 8: Iron (absorptiometric1: 10-phenant
10、hroline method); Part 9: Manganese (volumetric: arsenite/nitrite method); Part 10: Manganese (absorptiometric method); Part 11: Silicon (perchloric acid method); Part 12: Silicon (absorptiometric molybdenum blue method); Part 13: Titanium (absorptiometric chromotropic acid method); Part 14: Nickel (
11、gravimetric method); Part 15: Nickel (photometric method); Part 16: Chromium (photometric method); Part 17: Chromium (volumetric method); Part 18: Zinc (ion-exchange-volumetric EDTA or polarographic method); Part 19: Magnesium (atomic absorption method); Part 20: Lead (atomic absorption method); Par
12、t 21: Zinc (atomic absorption method); Part 22: Magnesium (volumetric CDTA method); Part 23: Copper (atomic absorption method). The preparation of this series of methods has been authorized by the Non-ferrous Metals Standards Committee as part of a general programme for the standardization of method
13、s for the sampling and analysis of non-ferrous metals. 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 appreciated that they are primarily intended as “referee” methods to be used in cases of dispute. This
14、 method is substantially the same as the corresponding method approved by ISO/TC79 which will be published as International Standard ISO3981 1) . A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct ap
15、plication. 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 and2, an inside back cover and a back cover. This standard has been updated (see copyright date
16、) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. 1) In course of preparation.BS1728-24:1976 BSI 12-1999 1 Introduction NOTEThe titles of the publications referred to in this standard are listed on the inside back cover. 1.1 Principl
17、e. The sample is dissolved in hydrochloric acid and diluted to a suitable volume and the nickel content is determined by atomic absorption spectrophotometry. 1.2 Range. The method is recommended for nickel contents between0.005% and3.0%. 1.3 Reproducibility. Experiments have been carried out indepen
18、dently 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. 2 Apparatus 2.1 Class A volumetric glassware complying with the appropriate British Standards shall be used throughout. The burette used sh
19、ould be graduated in0.05ml subdivisions. 2.2 Any atomic absorption spectrophotometer with adequate sensitivity and precision and preferably attached to a chart recorder readout or integrating device and capable of measuring absorption at a wavelength of232.0nm. A slot burner with air/acetylene flame
20、. A multi-slot burner is advisable when the total solid concentration in the solutions to be aspirated exceeds0.5%. 2.3 Nickel hollow cathode lamp 3 Solutions required All reagents shall be of the highest purity obtainable 2)and distilled or demineralized water shall be used throughout. Standard nic
21、kel (1mlN 0.125mg of nickel). Dissolve1.25g of high purity nickel (99.8%pure) in50ml of hydrochloric acid (50%), adding a few drops of hydrogen peroxide (100vol.) and warming gently if necessary to complete the dissolution. Boil to remove excess hydrogen peroxide, cool, dilute and transfer to a1litr
22、e volumetric flask, dilute to the mark and mix. Transfer100ml of this solution to a1litre volumetric flask, dilute to the mark and mix. Standard nickel (1mlN 0.025mg of nickel). Transfer200ml of standard nickel solution(1mlN 0.125mg of nickel) to a1litre volumetric flask, dilute to the mark and mix.
23、 Aluminium (2%w/v). Weigh20.0 0.01g of high purity aluminium (note8.1) and transfer to a1litre beaker. Add in small portions100ml of hydrochloric acid (50%), then add a drop of metallic mercury. Heat gently to start the reaction, then add in small portions a further400ml of hydrochloric acid(50%). W
24、hen the reaction subsides, add gradually250ml of special grade hydrochloric acid (sp.gr.1.16 to1.18) and heat gently if necessary to complete the reaction. Add a few millilitres of hydrogen peroxide (100vol.) and boil to remove excess hydrogen peroxide. Allow to cool, transfer to a1litre volumetric
25、flask, dilute to the mark and mix. Hydrochloric acid (50%v/v). Dilute500ml of special grade hydrochloric acid (sp.gr.1.16 to1.18) to1litre and mix. Nitric acid (50%v/v). Dilute100ml of nitric acid (sp.gr.1.42) to200ml and mix. 4 Sampling Recommended methods of obtaining a suitable sample for the ana
26、lytical procedure given below are described in BS1499. 5 Procedure 5.1 Weigh1.0 0.001g of sample, transfer to a250ml beaker (note8.2) and add30ml to40ml of water, then in small portions30ml of hydrochloric acid (50%) (note8.3). Cover with a watchglass and warm gently to complete the dissolution. Add
27、 a few millilitres of hydrogen peroxide (100vol.) and boil to remove excess hydrogen peroxide. 5.2 Carry out simultaneously a blank determination following the same procedure and using the same amounts of reagents as with the sample, and replacing the sample by1.0 0.001g of high purity aluminium (no
28、te8.1). 5.3 Filter if necessary through a close-textured filter paper 3) , wash the precipitate four times with water and add the washings to the sample solution. 5.3.1 For alloys containing up to1% of silicon. Discard the filter paper and residue and retain the solution. Nickel content Standard dev
29、iation s % % 0.03 0.0016 1.5 0.018 2) For certain reagents an extra high quality is now available but this special grade of material is not required unless specifically stated. 3) Whatman No.540 is suitable.BS1728-24:1976 2 BSI 12-1999 5.3.2 For alloys containing more than1% of silicon. Transfer the
30、 filter paper and residue to a platinum crucible using forceps, dry and ignite to burn off the paper. Allow to cool, add5ml of hydrofluoric acid 4)and five drops of nitric acid (sp.gr.1.42). When the reaction has subsided, evaporate carefully to dryness (note8.4), take up the residue in5ml of nitric
31、 acid (50%) and add to the main solution. 5.4 Transfer the solution to the appropriate size volumetric flask indicated in the following table: Dilute to the mark and mix. 5.5 Aspirate the solution (note8.2) and record the values of per cent absorption or absorbance depending upon the instrument and
32、type of readout. 6 Calibration 6.1 To a series of100ml volumetric flasks transfer the appropriate volume of aluminium solution (2%) indicated in the following table, then add from a burette the respective quantities of standard nickel solution (1mlN 0.025mg of nickel or1mlN 0.125mg of nickel) as sho
33、wn in the following table. 6.2 Dilute to the mark and mix. 6.3 Aspirate the solutions (note8.2) and record the values of per cent absorption or absorbance depending upon the instrument and type of readout. 6.4 Deduct the absorbance reading for the blank and prepare a calibration graph by plotting ab
34、sorbance values (seeclause7) against the nominal nickel contents of the solutions. 7 Calculation If the instrument reads per cent absorption, convert this to absorbance. Convert the absorbance reading for the test sample corrected for blank to percentage nickel by means of the calibration graph. 8 N
35、otes 8.1 Millings or drillings of99.99% purity aluminium should be used and these should be cleaned immediately before use with a little nitric acid (sp.gr.1.42), then washed with water and dried by washing with acetone. 8.2 The sample solution should be prepared at the same time as the calibration
36、standard solutions and aspirated immediately after the calibration solutions and blank without altering the instrument settings. After the last sample solution has been aspirated, it is advisable to aspirate the most concentrated standard solution once more. This is to ensure that instrument conditi
37、ons have not altered. (i.e.atomizer blocked, etc.). 8.3 For samples that are difficult to attack with hydrochloric acid, add a drop of metallic mercury. 8.4 If necessary repeat the treatment with hydrofluoric and nitric acids. 4) This refers to the usual analytical reagent grade of40%w/w. Nickel con
38、tent Volumetric size flask % ml 0.005 to 0.3 100 0.25 to 3 1000 Nickel solution Aluminium solution Standard nickel solution Corresponding nickel in sample 1 ml N 0.025 mg of nickel % ml ml mg 0.005 50 0, 2, 4, 12, 0.00, 0.05, to 0.3 20 0.10, 0.30, 0.50 1 ml N 0.125 mg of nickel 8, 12, 16, 1.00, 1.50
39、, 20, 24 2.00, 2.50, 3.00 0.25 5 0, 2, 4, 8, 0.00, 0.25, to 3 12, 16, 20, 0.50, 1.00, 24 1.50, 2.00, 2.50, 3.00BS1728-24:1976 BSI 12-1999 Publications referred to BS 1499, Sampling non-ferrous metals. ISO 3981, Aluminium alloys Determination of nickel 5) . 5) In course of preparation.BS 1728-24: 197
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