1、BRITISH STANDARD BS3907-15: 1976 Methods for The analysis of magnesium and magnesium alloys Part15: Lead in magnesium and magnesium alloys (atomic absorption method) UDC 669.721:543.422:546.815BS3907-15:1976 This BritishStandard, having been approved by the Non-ferrous Metals Industry Standards Comm
2、ittee, waspublished under theauthorityof the ExecutiveBoardon 31March1976 BSI12-1999 The following BSI references relate to the work on this standard: Committee references NFE/23 and NFE/23/4 Draft for comment73/41106 DC ISBN 0 580 08905 3 Co-operating organizations The Non-ferrous Metals Industry S
3、tandards 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 British Electrical and Allied Manufacturers
4、Association British Lead Manufacturers Association British Non-ferrous Metals Federation British Non-ferrous Metals Technology Centre* British Steel Industry Copper Development Association Department of Trade Electric Cable Makers Confederation Institute of British Foundrymen Institution of Mechanic
5、al Engineers Institution of Mining and Metallurgy Institution of Production Engineers Institution of Structural Engineers Lead Development Association Light Metal Founders Association London Metal Exchange Magnesium Industry Council* Ministry of Defence* National Brassfoundry Association Non-ferrous
6、 Metal Stockists* Post Office Royal Institute of British Architects Society of Motor Manufacturers and Traders Ltd.* Tin Research Institute Zinc Development Association Individual manufacturer The organizations marked with an asterisk in the above list, together with the following, were directly rep
7、resented on the committees entrusted with the preparation of this BritishStandard: Department of Industry Laboratory of the Government Chemist Institute of Sheet Metal Engineering Individual analysts Amendments issued since publication Amd. No. Date of issue CommentsBS3907-15:1976 BSI 12-1999 i Cont
8、ents Page Co-operating organizations Inside front cover Foreword ii 1 Introduction 1 2 Apparatus 1 3 Solutions required 1 4 Sampling 1 5 Procedure 1 6 Calibration 1 7 Calculation 2 8 Notes 2 Publications referred to Inside back coverBS3907-15:1976 ii BSI 12-1999 Foreword This method for the determin
9、ation of lead in magnesium and magnesium alloys is the fifteenth 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 a separate Part. Other methods in the series are as follows: Part1:
10、Aluminium in magnesium alloys (gravimetric method); Part2: Iron in magnesium and magnesium alloys (photometric-1:10 phenanthroline method); Part3: Copper in magnesium and magnesium alloys (photometric method); Part4: Manganese in magnesium and magnesium alloys (photometric-periodate method); Part5:
11、Manganese in magnesium and magnesium alloys (photometric-periodate method) (low contents); Part6: Zirconium in magnesium and magnesium alloys (photometric method); Part7: Nickel in magnesium alloys (photometric method); Part8: Total rare earths in magnesium alloys (gravimetric method); Part9: Zinc i
12、n magnesium alloys (ion-exchange-volumetric EDTA method); Part10: Manganese in magnesium alloys containing zirconium, rare earths or thorium (photometric method); Part11: Silicon in magnesium and magnesium alloys; Part12: Aluminium in magnesium and magnesium alloys (photometric method); Part13: Tin
13、in magnesium and magnesium alloys; Part14: Zirconium and thorium in magnesium alloys (volumetric 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 for the standardization of methods for the sam
14、pling 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. NOTEThe titles of
15、 the BritishStandards referred to in this standard are listed on the inside back cover. A British Standard does not purport 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
16、itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 and 2, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be
17、indicated in the amendment table on the inside front cover.BS3907-15:1976 BSI 12-1999 1 1 Introduction 1.1 Principle. The sample is dissolved in a mixture of nitric and hydrochloric acids and diluted to a suitable volume and the lead content is determined by atomic absorption spectrophotometry. 1.2
18、Range. The method is recommended for lead contents up to0.3%. 1.3 Reproducibility. Experiments have been carried out independently 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
19、 Class A volumetric glassware complying with the requirements of the appropriate BritishStandards shall be used throughout. 2.2 Any atomic absorption spectrophotometer with adequate sensitivity and precision and preferably attached to a chart recorder read out or integrating device and capable of me
20、asuring absorption at a wavelength of283.3nm (Note8.1). A slot burner with air/acetylene flame. 3 Solutions required All reagents shall be of the highest purity obtainable and either distilled or demineralized water complying with the requirements of BS3978 shall be used throughout. Solutions shall
21、be freshly prepared and where necessary filtered. Standard lead (1mlN 0.1mg of lead). Dissolve1.0 0.001g of high purity lead(99.99% pure) in the minimum amount of nitric acid(50%). Boil to remove nitrous fumes, cool, transfer to a1litre volumetric flask, dilute to the mark and mix. Transfer100ml of
22、this solution to a1litre volumetric flask, dilute to the mark and mix. Nitric acid (50%v/v), Dilute500ml of nitric acid (sp. gr.1.42) to1litre and mix. 4 Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS1499 “Sampling non-ferrous
23、 metals”. 5 Procedure 5.1 Weight1.0 0.001g of sample, transfer to a250ml beaker (Note8.2) and add20ml of water. Slowly add in small portions a freshly prepared mixture of15ml of hydrochloric acid (sp. gr.1.161.18) and5ml of nitric acid (sp. gr.1.42), and warm gently to complete the dissolution. 5.2
24、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 magnesium(99.99% pure). 5.3 With the beaker covered, evaporate the solution to about10ml and allow to cool. Take
25、 up the residue in25ml of water, warm gently to complete the solution and cool. Filter if necessary through a paper-pulp pad, wash the precipitate with a small amount of water and add the washings to the sample solution. 5.4 Transfer the solution to a100ml volumetric flask, dilute to the mark and mi
26、x. 5.5 Aspirate the solution (Note8.2) and record the values of per cent absorption or absorbance, depending upon the instrument and type of read out. 6 Calibration 6.1 To a series of250ml beakers transfer1.0 0.001g of high purity magnesium(99.99% pure) and add20ml of water. Slowly add to each in sm
27、all portions a freshly prepared mixture of15ml of hydrochloric acid (sp. gr.1.161.18) and5ml of nitric acid (sp. gr.1.42) and warm gently to complete the dissolution. 6.2 Add respectively: 0,5.0,10.0,15.0,20.0,25.0 and30.0ml of standard lead solution(1mlN 0.1mg of lead) equivalent to0,0.05,0.10,0.15
28、,0.20,0.25, and0.30% of lead. 6.3 Continue from5.3 of the procedure. 6.4 Aspirate the solutions (Note8.2) and record the values of per cent absorption or absorbance, depending upon the instrument and type of read out. Lead content Standard deviation s % 0.015 0.023 0.074 0.13 0.21 0.0027 0.0016 0.00
29、70 0.0047 0.0052BS3907-15:1976 2 BSI 12-1999 6.5 Deduct the absorbance reading for the blank and prepare a calibration graph by plotting absorbance values (see7 Calculation) against the nominal lead contents of the solutions. 7 Calculation If the instrument reads per cent absorption, convert this to
30、 absorbance. Convert the absorbance reading for the test sample corrected for blank to percentage lead by means of the calibration graph. 8 Notes 8.1 The line at a wavelength of217nm is the most sensitive line for lead but there is background absorption from the air/acetylene flame at this wavelengt
31、h; also the secondary line at283.3nm has stronger emission from the hollow cathode lamp. 8.2 The sample solution should be prepared at the same time as the calibration standard solutions and aspirated immediately after the calibration solutions and blank, without altering the instrument settings. Af
32、ter 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 conditions have not altered (i.e.atomizer blocked etc.).BS3907-15:1976 BSI 12-1999 Publications referred to This standard makes reference
33、to the following BritishStandards: BS1499, Sampling non-ferrous metals. BS3978, Water for laboratory use. BS3907-15: 1976 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the UK view o
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