1、BRITISH STANDARD BS3908-6: 1971 Method for The determination of tellurium in lead and lead alloys (Photometric method) Methods for the sampling and analysis of lead and lead alloysBS3908-6:1971 This British Standard, having been approved by the Non-ferrous Metals Industry Standards Committee, was pu
2、blished under the authority ofthe Executive Board on 15 October1971 BSI12-1999 The following BSI references relate to the work on this standard: Committee references NFE/22, NFE/22/6 Draft for comment69/22086 ISBN 580 06825 0 Co-operating organizations The Non-ferrous Metals Industry Standards Commi
3、ttee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments and scientific and industrial organisations: Aluminium Federation Institution of Mining and Metallurgy Association of Bronze and Brass Founders Institution of Produ
4、ction Engineers British Bronze and Brass Ingot Manufacturers Institution of Structural Engineers Association Lead Development Association* British Electrical and Allied Manufacturers Light Metal Founders Association Association London Metal Exchange British Lead Manufacturers Association* Magnesium
5、Industry Council British Non-ferrous Metals Federation Ministry of Defence, Army Department British Non-ferrous Metals Federation, High Ministry of Defence, Navy Department Conductivity Copper Group National Brassfoundry Association British Non-ferrous Metals Research Non-ferrous Metal Stockists Ass
6、ociation* Post Office* Copper Development Association Royal Institute of British Architects Department of Trade and Industry (Marine Society of Motor Manufacturers and Traders Division) Ltd. Electric Cable Makers Confederation* Tin Research Institute Institute of British Foundrymen Zinc Development
7、Association Institute of Metals Individual manufacturers Institution of Mechanical Engineers (Automobile Division) The 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 prepara
8、tion of this British Standard: Accumulator Makers Association Ministry of Defence British Battery Makers Society Solder Makers Association Chemical Industries Association United Kingdom Atomic Energy Authority London Transport Executive Amendments issued since publication Amd. No. Date CommentsBS390
9、8-6:1971 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 7 Notes 2BS3908-6:1971 ii BSI 12-1999 Foreword This standard makes reference to the following British Standa
10、rds: BS3908, Methods for the sampling and analysis of lead and lead alloys Part1:Sampling of ingot lead, lead alloy ingots, sheet, pipe and cable sheathing alloys. BS3978, Water for laboratory use. This method for the determination of tellurium in lead and lead alloys is the sixth of a series of met
11、hods 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 been authorized by the Non-ferrous Metals Industry Standards Comm
12、ittee 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 cable sheathing alloys; Part 2: Determination of arsenic in lead
13、 and lead alloys (photometricmethod); Part 3: Determination of bismuth in lead and lead alloys (photometricmethod); Part 4: Determination of copper in lead and lead alloys (photometricmethod); Part 5: Determination of nickel in lead and lead alloys (photometric method); Part 7: Determination of silv
14、er in lead 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 (volumetricmethod); Part 11: Determination of tin in lead and lead alloys (volumetric
15、 method); Part 12: Determination of zinc in lead and lead alloys 1) ; Part 13: Determination of antimony in lead and lead alloys (low contents) (photometric method); Part 14: Determination of tin in lead and lead alloys (low contents) 1) ; Part 15: Determination of iron in lead and lead alloys (phot
16、ometricmethod) 1) . The complete British Standard methods will be found suitable for the grades of metals covered by BS334, “Chemical lead”, BS335, “Regulus metal”, BS602 and BS1085, “Lead and lead alloy pipes for other than chemical purposes”, BS801, “Lead and lead alloy sheaths of electric cable”,
17、 BS1178, “Milled 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 “refer
18、ee” methods to be used in cases of dispute. 1) In course of preparation.BS3908-6:1971 BSI 12-1999 iii 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 Standar
19、d does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi toiv, pages1and2 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated i
20、n the amendment table on the inside front cover.iv blankBS3908-6:1971 BSI 12-1999 1 1 Introduction 1.1 Principle. Tellurium is first separated in the elemental form by treatment with stannous bromide. After re-solution in hydrobromic acid the tellurium is determined photometrically as the bromide. 1
21、.2 Range. From0.005 to0.1% tellurium. 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: 1.4 Application. The method is applicab
22、le to lead and lead alloys containing up to12% antimony. 2 Apparatus 2.1 Any volumetric glassware used shall be of ClassA accuracy as defined in the appropriate British Standards. 2.2 Any instrument suitable for measuring the optical density of the solution at a wavelength of442nm may be used togeth
23、er with a4 or1cm cell (Note7.1). Alternatively, when a filter photometer of the balanced two-photo-cell type is used, the following conditions have been found suitable (Note7.2): Tungsten lamp Kodak No.1 filter with Calorex H503 heat filter or equivalent filters4 or2cm cell (Note7.3). 3 Solutions re
24、quired All reagents shall be of the highest purity obtainable and distilled or demineralized water complying with BS3978 2)shall be used throughout. Solutions shall be freshly prepared and where necessary filtered. Standard tellurium (1mlN 0.25mg of tellurium). Dissolve0.25g of metallic tellurium in
25、 bromine-hydrobromic acid. Transfer to a1litre volumetric flask, dilute to the mark with the bromine-hydrobromic acid and mix. Standard tellurium (1ml N 0.05mg of tellurium). Transfer100ml of standard tellurium solution(1ml N 0.25mg of tellurium) to a500ml volumetric flask, dilute to the mark with t
26、he bromine-hydrobromic acid and mix. Ascorbic acid (10%w/v). Dissolve10g of ascorbic acid in water, dilute to100ml and mix. Bromine-hydrobromic acid. To95ml of hydrobromic acid (sp.gr.1.461.49) add5ml of bromine. Stannous bromide (25%w/v). Dissolve25g of stannous bromide in10ml of hydrobromic acid (
27、sp.gr.1.461.49). Dilute to100ml and mix. ALTERNATIVELY: Dissolve10g of high purity tin in50ml of hydrobromic acid (sp.gr.1.461.49). 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 i
28、ngot lead, lead alloy ingots, sheet, pipe and cable sheathing alloys”. 5 Procedure 5.1 Weigh2g of sample and transfer to a250ml beaker. Add20ml of the bromine-hydrobromic acid, warming if necessary until solvent action ceases. Then boil for5minutes to remove excess of free bromine. 5.2 Cool to appro
29、ximately60 C, add5ml of stannous bromide solution(25%), mix well and allow to stand for1hour (Note7.4). 5.3 Filter under suction through a No.4 sintered glass crucible using all glass apparatus. Wash the beaker and the precipitate first with stannous bromide solution(25%) and finally with water. 5.4
30、 Remove the suction from the Buchner flask and place a receiver inside the flask. Using a pipette wash the walls of the crucible with10ml of the bromine-hydrobromic acid to dissolve any tellurium not on the sintered disc. After3 to4minutes again apply suction and wash the crucible with water, collec
31、ting the filtrate and the washings in the receiver. Transfer these to the original beaker and boil until the volume is reduced to about10ml (Note7.5). 5.5 Cool, add35ml of hydrobromic acid (sp.gr.1.461.49) and10ml of ascorbic acid solution(10%) and transfer the solution to a100ml volumetric flask, w
32、ashing the beaker with10ml of water and adding the washings to the flask. Dilute to the mark with hydrobromic acid (sp.gr.1.461.49). 5.6 Measure the optical density using the conditions specified under2, Apparatus. Tellurium content Standard deviation s % 0.0056 0.033 0.0004 0.002 2) BS3978, “Water
33、for laboratory use”.BS3908-6:1971 2 BSI 12-1999 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 calculate the percentage tellurium in the sample by reference t
34、o the appropriate calibration graph. 6 Calibration 6.1 For tellurium contents between0.005 and0.025% 6.1.1 Transfer0,2.0,4.0,6.0,8.0 and10ml of standard tellurium solution(1ml N 0.05mg of tellurium) to a series of250ml conical beakers and add to each2g of pure lead. Then add to each20ml of the bromi
35、ne-hydrobromic acid, boil for5minutes and continue from5.2 of the Procedure. 6.1.2 Measure the optical density using the conditions specified under2, Apparatus, and prepare a calibration graph by plotting the optical density against the weight of tellurium in the various aliquots after deduction of
36、the blank reading. 6.2 For tellurium contents between0.025 and0.10% 6.2.1 Transfer0,2.0,4.0,6.0 and8.0ml of standard tellurium solution(1ml N 0.25mg of tellurium) to a series of250ml conical beakers and add to each2g of pure lead. Then add to each20ml of the bromine-hydrobromic acid, boil for5minute
37、s and continue from5.2 of the Procedure. 6.2.2 Measure the optical density using the conditions specified under2, Apparatus, and prepare a calibration graph by plotting the optical density against the weight of tellurium in the various aliquots after deduction of the blank reading. 7 Notes 7.1 A4cm
38、cell should be used for tellurium contents in the range0.005 to0.025% and a1cm cell for tellurium contents in the range0.02 to0.10%. 7.2 With this type of instrument the accuracy may be diminished at the0.005% level. 7.3 A4cm cell should be used for tellurium contents in the range0.005 to0.025% and
39、a2cm cell for tellurium contents in the range0.02 to0.10%. 7.4 The precipitated elemental tellurium is allowed to stand for1hour at60 C, to enable crystal growth and aggregation of the precipitate to occur so that this can then be conveniently filtered. If filtration is attempted too early either th
40、e precipitate is not retained by the sintered glass filter or the precipitate closes the pores of the sinter and the time of filtration is considerably lengthened. 7.5 The last part of the evaporation should be done slowly and dry spots should not be allowed to form on the bottom of the beaker.blank
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