1、BRITISH STANDARD BS1728-9: 1957 Method for The determination of manganese in aluminium and aluminium alloys (Volumetric: arsenite/nitrite method)BS1728-9:1957 This British Standard, having been approved by the Non-ferrous Metals Industry Standards Committee and endorsed by the Chairman of theEnginee
2、ring Divisional Council, was published under theauthority of the GeneralCouncil on 12September1957 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference NFE/-/3 Draft for comment CW(NFE)8554 ISBN 0 580 01539 4 Co-operating organizations The Non-ferrous Met
3、als Industry Standards Committee, under whose supervision this British Standard was prepared, consists of representatives from the following Government departments, and scientific and industrial organizations: Admiralty* High Conductivity Copper Association Aluminium Development Association* Institu
4、te of British Foundrymen Aluminium Industry Council* Institute of Metals Association of Bronze and Brass Founders Institution of Mechanical Engineers Association of Consulting Engineers, (Automobile Division) Incorporated Institution of Mining and Metallurgy Association of Non-ferrous Metal Stockist
5、s Institution of Structural Engineers Brass and Copper Tube Association Lead Sheet and Pipe Manufacturers Brass Wire Association Federation British Bronze and Brass Ingot Light Metal Founders Association* Manufacturers Association London Metal Exchange British Electrical and Allied Manufacturers Man
6、ufactured Copper Association Association Ministry of Supply* British Non-ferrous Metals Research National Brassfoundry Association Association* Nickel Silver Association Cable Makers Association Royal Institute of British Architects Cold Rolled Brass and Copper Association Society of British Aircraf
7、t Constructors Copper Development Association Society of Motor Manufacturers and Crown Agents for Oversea Governments and TradersLtd. Administrations Tin Research Institute General Post Office Zinc Development Association High Commission of India Individual manufacturers The Government departments a
8、nd scientific and industrial organizations marked with an asterisk in the above list, together with the following, were directly represented on the sub-committee entrusted with the preparation of this British Standard: ALAR (Association of Light Alloy Refiners) Individual analysts Department of the
9、Government Chemist Amendments issued since publication Amd. No. Date CommentsBS1728-9:1957 BSI 11-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii Introduction 1 Special apparatus 1 Solutions required 1 Sampling 2 Procedure 2BS1728-9:1957 ii BSI 11-1999 Foreword This st
10、andard makes reference to the following British Standard: BS1499, Sampling non-ferrous metals. This method for the determination of manganese is the ninth of a series of methods for the analysis of aluminium and aluminium alloys. It is intended mainly for use with alloys containing higher percentage
11、s of manganese than those dealt with in the absorptiometric method given in Part10. This series will form a complete British Standard, each method being published as a separate part. Other methods in the series are as follows: Part 1: Copper; Part 2: Magnesium; Part 3: Zinc (mercuric potassium thioc
12、yanate method); Part 4: Zinc (polarographic method); Part 5: Copper (absorptiometric method); Part 6: Iron (volumetric titanous chloride method); Part 7: Zinc (zinc oxide method); Part 8: Iron (absorptiometric1:10-phenanthroline method); Part 10: Manganese (absorptiometric method). The preparation o
13、f this series of methods has been authorized by the Non-ferrous Metals Industry Standards Committee as part of a general programme of the standardization of methods for the analysis of non-ferrous metals. These methods have been found to give reliable and reproducible results and, while in some inst
14、ances the methods may appear to be lengthy, it should be realized that they are put forward 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. Users of British Standards are responsible for their correct app
15、lication. 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 standard has been updated (see copyright date) and may have had ame
16、ndments incorporated. This will be indicated in the amendment table on the inside front cover.BS1728-9:1957 BSI 11-1999 1 Introduction a) Principle. The alloy is dissolved by means of sodium hydroxide solution followed by an acid mixture. The manganese is oxidized by ammonium persulphate in the pres
17、ence of silver nitrate and the permanganic acid is titrated with arsenite/nitrite solution. b) Range. The method is suitable for manganese contents between0.1 and1.5per cent and is applicable to alloys containing up to0.5per cent chromium. c) Reproducibility. Experiments have been carried out by a n
18、umber of independent analysts using the method recommended in this standard. The degree of reproducibility that can be expected is shown by the following analysis of the results obtained: Special apparatus Any volumetric glassware used shall be of Class A accuracy, as defined in the appropriate Brit
19、ish Standards or, where no British Standard exists, as described in the National Physical Laboratory publication “Volumetric tests on volumetric glassware”. Solutions required All reagents used in making these solutions shall be of recognized analytical quality and distilled water shall be used thro
20、ughout. Manganese found (mean)per cent Standard deviation 0.137 0.342 0.499 1.039 1.548 0.0047 0.0051 0.0092 0.0129 0.0144 Acid mixture Phosphoric acid (sp. gr.1.75) 500ml Sulphuric acid (sp. gr.1.84) 250ml Nitric acid (sp. gr.1.42) 200ml Water 1 550ml Add the sulphuric acid cautiously to the water.
21、 Cool, and add the phosphoric and nitricacids. Ammonium chloride (0.15per cent w/v aqueous). Ammonium persulphate (25per cent w/v aqueous). This solution shall be freshly prepared. Potassium dichromate (0.5per cent w/v aqueous). Standard manganese. Dissolve a weighed quantity of electrolytic mangane
22、se of known manganese content in10ml of nitric acid(1:1), the quantity weight being such as will give0.5000g of manganese. Cool, and dilute to one litre. Sodium arsenite (0.05N approx.). Dissolve2.47g of arsenous oxide in25ml of warm water containing1.5g of sodium hydroxide. Add4g of sodium hydrogen
23、 carbonate, cool and dilute to one litre. Sodium nitrite (0.05N approx.). Dissolve1.72g of sodium nitrite (previously dried at105110 C for one hour) in water and dilute to one litre. Arsenite/nitrite mixture (0.05N approx.). Mix660ml of the sodium arsenite solution with340ml of the sodium nitrite so
24、lution. Silver nitrate (0.12per cent w/v aqueous). Sodium hydroxide (20per cent w/v aqueous).BS1728-9:1957 2 BSI 11-1999 Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS1499, “Sampling non-ferrous metals”. Procedure Adjust the w
25、eight of sample as follows: Treat the accurately weighed sample in a covered500-ml conical beaker (with a mark at230ml) with25ml of sodium hydroxide solution(50ml for a2g sample) and simmer on a hot plate until all visible action ceases (see note). Cool somewhat, then add60ml of the acid mixture(100
26、ml for a2g sample), wash down the sides of the beaker and boil gently until solution is complete and nitrous fumes are expelled. Add a few particles of crushed silica to prevent bumping, dilute to the230-ml mark with hot water, and add10ml of the silver nitrate solution and10ml of the ammonium persu
27、lphate solution. Heat to boiling point and boil gently for one minute after the initial formation of permanganic acid. Cool to20 3 C, add3ml of the potassium dichromate solution (to improve the end-point) then add10ml of the ammonium chloride solution to precipitate the silver. Titrate with arsenite
28、/nitrite mixture until the permanganic acid is completely reduced and one drop produces no further change in colour. Standardization of arsenite/nitrite mixture. Dissolve1g of manganese-free pure aluminium in25ml of sodium hydroxide solution, add10.0ml of the standard manganese solution, and acidify
29、 with60ml of the acid mixture. Continue as described under procedure. Carry out the standardization in triplicate and from the mean of the results calculate the strength of the arsenite/nitrite mixture in terms of manganese. This standardization should be carried out with each batch of determination
30、s. NOTEFor silicon contents greater than4per cen concentrate the solution at this stage to about half volume. Manganese content per cent Weight of sample g 0.10.25 0.251.0 1.01.5 2 1 0.5blankBS1728-9: 1957 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent
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