1、BRITISH STANDARD BS 3908-2: 1967 Method for The determination of arsenic in lead and lead alloys (photometric method)BS3908-2:1967 This British Standard, having been approved by the Non-ferrousMetals Industry Standards Committee and endorsed by the Chairman of theEngineering Divisional Council, was
2、published under theauthority of the General Council on 22 March1967 BSI12-1999 The following BSI references relate to the work on this standard: Committee references NFE/22, NFE/22/6 Draft for commentD65/9009 ISBN 0 580 04441 6 Co-operating organizations The Non-ferrous Metals Industry Standards Com
3、mittee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments, and scientific and industrial organizations: Aluminium Federation Institution of Mining and Metallurgy Association of Bronze and Brass Founders Institution of Pr
4、oduction Engineers Association of Consulting Engineers Institution of Structural Engineers Board of Trade Lead Development Association* British Bronze and Brass Ingot Manufacturers Light Metal Founders Association Association London Metal Exchange British Electrical and Allied Manufacturers Magnesiu
5、m Industry Council Association Ministry of Defence, Army Department British Lead Manufacturers Association* Ministry of Defence, Navy Department* British Non-ferrous Metals Federation* National Brassfoundry Association British Non-ferrous Metals Research Non-ferrous Metal Stockists Association* Post
6、 Office* Copper Development Association Royal Institute of British Architects Crown Agents for Oversea Governments and Society of British Aerospace Companies Ltd. Administrations Society of Motor Manufacturers and Traders Electric Cable Makers Confederation* Ltd. High Conductivity Copper Association
7、 Tin Research Institute Institute of British Foundrymen Zinc Development Association Institute of Metals Individual manufacturers Institution of Mechanical Engineers (Automobile Division) The Government department and scientific and industrial organizations marked with an asterisk in the above list,
8、 together with the following, were directly represented on the committee entrusted with the preparation of this British Standard: Accumulator Makers Association London Transport Board British Battery Makers Association United Kingdom Atomic Energy Authority Amendments issued since publication Amd. N
9、o. Date CommentsBS3908-2:1967 BSI 12-1999 i Contents 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 2 Figure 1 Distillation apparatus 3BS3908-2:1967 ii BSI 12-1999 Foreword This standard ma
10、kes reference to the following British Standards: BS 572, Interchangeable conical ground glass joints. BS 3908, Methods for the sampling and analysis of lead and lead alloys Part1:Sampling of ingot lead, lead alloy ingots, sheet, pipe and cable sheathingalloys. This method for the determination of a
11、rsenic in lead and lead alloys, is the second of a series of methods which will form a complete British Standard under the collective title “Methods for the sampling and analysis of lead and lead alloys”, each method being published as a separate part. The preparation of this series of methods has b
12、een 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. Other methods in the series are as follows: Part 1: Sampling of ingot lead, lead alloy ingots, sheet, pipe and
13、cable sheathing alloys; Part 3: Determination of bismuth in lead and lead alloys; Part 4: Determination of copper in lead and lead alloys; Part 5: Determination of nickel in lead and lead alloys 1) ; Part 6: Determination of tellurium in lead and lead alloys 1) ; Part 7: Determination of silver in l
14、ead and lead alloys 1) ; Part 8: Determination of cadmium in lead and lead alloys 1) ; Part 9: Determination of sulphur in lead and lead alloys 1) ; Part 10: Determination of antimony in lead and lead alloys; Part 11: Determination of tin in lead and lead alloys 1) ; Part 12: Determination of zinc i
15、n lead and lead alloys 1) . The complete British Standard methods will be found suitable for the grades of metals covered by BS334 “Chemical lead”, BS335 “Regulus metal”, BS602 andBS1085 “Lead pipes for other than chemical purposes”, BS801 “Lead and lead alloy sheaths of electric cable”, BS1178 “Mil
16、led lead sheet and strip for building purposes” and BS3909 “Ingot lead for radiation shielding”. 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 realized that they are put forward as “referee” methods to
17、be used in cases of dispute. 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 itself confer immunity from legal obligations. Summary of p
18、ages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to3 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. 1) In course of prepara
19、tionBS3908-2:1967 BSI 12-1999 1 1 Introduction 1.1 Principle. After separation by distillation of the trichloride, arsenic is determined photometrically as the reduced arsenomolybdate complex. 1.2 Range. From0.001% up to0.01% of arsenic. 1.3 Reproducibility. Experiments have been carried out indepen
20、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 Any volumetric glassware used shall be of ClassA accuracy as defined in the appropriate British Standards, or where no Brit
21、ish Standard exists, as described in the National Physical Laboratory Publication “Volumetric Tests on Volumetric glassware”. 2.2 Any instrument suitable for measuring the optical density of the solution at a wavelength of830m4 may be used together with4cm cells. Alternatively, when a filter photome
22、ter of the balanced two-cell type is used the following conditions have been found suitable: Tungsten lamp Ilford609 or equivalent filter 2cm cells. 3 Solutions required All reagents shall be of the highest purity obtainable and distilled or demineralized water shall be used throughout. Solutions sh
23、all be freshly prepared and, where necessary, filtered. Standard arsenic. (1mlN 0.1mg of arsenic). Dissolve0.132g of arsenous oxide in2ml of sodium hydroxide solution(5%w/v). Dilute to approximately50ml and add1ml of hydrochloric acid (sp. gr.1.161.18). Transfer to a1litre volumetric flask, dilute t
24、o the mark and mix. Ammonium molybdate (1%w/v). Dissolve1g of ammonium molybdate (NH 4 ) 6 Mo 7 O 24 .4H 2 O in sulphuric acid(20%v/v), dilute to100ml with sulphuric acid(20%v/v) and mix. Hydrazine sulphate (0.15%w/v). Dissolve0.15g ofhydrazine sulphate in water, dilute to100ml andmix. Ammonium moly
25、bdate hydrazine sulphate. Dilute10ml of ammonium molybdate solution(1%) to90ml, add1ml of hydrazine sulphate solution(0.15%), dilute to100ml and mix. 4 Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS3908-1, “Sampling of ingot l
26、ead, lead alloy ingots, sheet, pipe and cable sheathing alloys”. 5 Procedure 5.1 Weigh2g of sample and transfer to a500ml flat-bottomed flask fitted with a joint of size24/29 (also known as B24) complying with the requirements of BS572 2) . Add20ml of sulphuric acid (sp. gr.1.84) and heat gently unt
27、il the initial reaction is complete, then strongly until the space inside the flask is free from white fumes. 5.2 Cool, add30ml of water and cool again. Addcarefully120ml of hydrochloric acid (sp.gr.1.161.18) and0.2g of hydrazine sulphate. 5.3 Distil the solution in an all-glass apparatus (Figure 1)
28、 collecting the distillate in a250ml beaker cooled in running water and containing50ml of water and5ml of nitric acid (sp. gr.1.42). Continue the distillation until the volume in the flask is reduced to8090ml after3035 minutes then remove the beaker containing the distillate and add10ml of nitric ac
29、id (sp. gr.1.42). 5.4 Evaporate almost to dryness. Place in an ovenat110 C and complete the evaporation (about1020 minutes) but avoid baking. 5.5 Cool and add70ml of the ammonium molybdate-hydrazine sulphate solution, heat in a water bath at100 C for20minutes. Cool, transfer to a100ml volumetric fla
30、sk and dilute to the mark. 5.6 Measure the optical density under the conditions specified under “Apparatus”. 5.7 Carry out simultaneously a blank determination on the reagents, following the same procedure without the sample and using the same quantity of reagents. 5.8 Deduct the blank reading and c
31、alculate the percentage of arsenic in the sample by reference to the appropriate calibration graph. Arsenic content Standard deviation s % 0.010 % 0.001 2) BS572, “Interchangeable conical ground glass joints”.BS3908-2:1967 2 BSI 12-1999 6 Calibration 6.1 Transfer0,0.5,1.0,2.0,3.0 and5.0ml aliquots o
32、f standard arsenic solution(1mlN 0.1mg of arsenic) to a series of250ml beakers, add to each5ml of water,1ml of hydrochloric acid (sp.gr.1.161.18) and1ml of nitric acid (sp.gr.1.42). Continue from paragraph5.4 of the procedure. 6.2 Measure the optical density using the conditions specified under “App
33、aratus” and prepare a calibration graph by plotting the optical density against the weight of arsenic in the various aliquots after deduction of the blank reading. BS 3908-2:1967 BSI 12-1999 3 Figure 1 Distillation apparatusBS 3908-2: 1967 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandards
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