1、BRITISH STANDARD BS1748-6: 1960 Method for The determination of tin in copper alloys (Nickel coil reduction method) Methods for the analysis of copper alloysBS1748-6:1960 This British Standard, having been approved by the Non-ferrousMetals Industry Standards Committee and endorsed by the Chairman of
2、 theEngineering Divisional Council, was published under theauthority of the General Council on 20 July1960 BSI 10-1999 The following BSI references relate to the work on this standard: Committee reference NFE/-/2 Draft for comment CZ(NFE) 8589 ISBN 0 580 35606 X Co-operating organizations The Non-fe
3、rrous Metals 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* Institution of Mechanical Engineers Aluminium Development Association
4、(Automobile Division) Aluminium Industry Council Institution of Mining and Metallurgy Association of Bronze and Brass Founders* Institution of Structural Engineers Association of Consulting Engineers, Lead Development Association Incorporated Lead Sheet and Pipe Manufacturers Association of Non-ferr
5、ous Metal Stockists Federation British Bronze and Brass Ingot Manufacturers Light Metal Founders Association Association* London Metal Exchange British Electrical and Allied Manufacturers Magnesium Industry Council Association Ministry of Aviation* British Non-ferrous Metals Federation National Bras
6、sfoundry Association British Non-ferrous Metals Research Post Office Association* Royal Institute of British Architects Cable Makers Association Society of British Aircraft Constructors Copper Development Association Society of Motor Manufacturers and Traders Crown Agents for Oversea Governments and
7、 Limited Administrations Tin Research Institute High Commission of India War Office High Conductivity Copper Association Zinc Development Association Institute of British Foundrymen Individual manufacturers Institute of Metals The Government departments and scientific and industrial organizations ma
8、rked 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: D.S.I.R.Laboratory of the Government Chemist Individual firms Amendments issued since publication Amd. No. Date CommentsBS1748
9、-6:1960 BSI 10-1999 i Contents Page Co-operating organizations Inside front cover Foreword ii Introduction 1 1 Apparatus 1 2 Solutions required 1 3 Sampling 1 4 Standardization 1 Figure 1 Assembly for reduction of tin 2BS1748-6:1960 ii BSI 10-1999 Foreword This standard makes reference to the follow
10、ing British Standards: BS1400, Copper alloy ingots and castings. BS1499, Sampling non-ferrous metals. This method for the determination of tin is one of a series of methods for the analysis of copper alloys, which will form a complete British Standard issued in several parts. The methods are intende
11、d primarily for the analysis of the copper alloys included in BS1400, “Copper alloy ingots and castings”, and those being included in the series of schedules of wrought copper and copper alloys, BS2870 to BS2875, of which BS2871 has already been published, and the remainder are in course of preparat
12、ion. 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 be used in cases of dispute. A British Standard does not purport to include all the necessary p
13、rovisions 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 pages This document comprises a front cover, an inside front cover, pagesi andii, pages1 to3 and
14、 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.BS1748-6:1960 BSI 10-1999 1 Introduction a) Principle. The sample is dissolved in a mixture of nitric and hydrochloric
15、acids. Tin is precipitated as the hydroxide, using iron hydroxide as the collector, then determined iodimetrically after reduction with nickel. b) Range. 1.0to14.0per cent tin. c) Reproducibility. Experiments have been carried out independently by a number of analysts using the method recommended in
16、 this standard. The degree of reproducibility that can be expected is shown by the following analysis of the results obtained: d) Application. The method is suitable for application to phosphor bronze and gun metals. 1 Apparatus a) Grade A graduated glassware shall be used throughout. b) A suitable
17、form of apparatus is illustrated in Figure 1. The nickel coil should be activated before use as follows: Dip the coil in nitric acid (sp. gr.1.42) for a few seconds then rinse in cold water and immerse for5minutes in a boiling solution of the following composition: Wash well in cold water and leave
18、immersed in cold water until required. 2 Solutions required All reagents shall be of the highest purity obtainable and distilled water shall be used throughout. Solutions shall be freshly prepared and, where necessary, filtered. Potassium iodate/iodide (N/20). Dissolve3.567g of potassium iodate (pre
19、viously dried at105to110 C) in200ml of hot water. Cool, add40g of potassium iodide and10ml of sodium hydroxide solution (N). Dilute to2litres in a graduated flask.1mlN approx. 3mg of tin. Standard tin (1mlN 5mg of tin). Dissolve0.500g of pure tin in50ml of hydrochioric acid(50percentv/v) and dilute
20、to100ml in a graduated flask. Ammonium sulphate (1per cent w/v). Dissolve10g of ammonium sulphate1litre of water and make just alkaline with ammonia solution (sp. gr.0.91). Antimony chloride (2per cent w/v). Dissolve2g of antimony chloride in10ml of hydrochloric acid(50per cent v/v). Ferric chloride
21、 (10per cent w/v). Dissolve10g of ferric chloride in100ml of hydrochloric acid(1percent v/v). Hydrochloric acid (50per cent v/v). Dilute500ml of hydrochloric acid (sp. gr.1.161.18) to1litre. Hydrochloric acid (1per cent v/v). Dilute10ml of hydrochloric acid (sp. gr.1.161.18) to1litre. Sodium hydroge
22、n carbonate. Saturated solution. Starch (0.5per cent w/v). Make a suspension of0.5g of starch in10ml of water. Add to90ml of boiling water. Cool and dilute to100ml. 3 Sampling Recommended methods of obtaining a suitable sample for the analytical procedure given below are described in BS1499, “Sampli
23、ng non-ferrous metals”. 4 Standardization To pure copper equal in weight to that of the sample, add a volume of the standard tin solution equivalent to the amount of tin to be titrated and apply the entire procedure, including a blank determination. In no instance should the volume of standard tin s
24、olution added be less than10ml. Express the factor in terms of milligrams tin per millilitre of the standard iodate/iodide solution. Procedure Weigh the sample accurately and transfer to a400ml beaker. Add30ml of hydrochloric acid (sp.gr.1.161.18) then30ml of nitric acid (sp.gr.1.42), allow to stand
25、 on the hot plate to expel nitrous fumes then dilute to about125ml with warm water. Carry out simultaneously a blank determination on the reagents. Tin content Standard deviation per cent 1.0 14.0 per cent 0.04 0.1 water 300ml hydrochloric acid (sp. gr.1.161.18) 100ml ferric chloride 50g Tin content
26、 Weight of sample per cent Below2.0 2.05.0 5.014.0 g 5.0 2.0 1.0BS1748-6:1960 2 BSI 10-1999 Figure 1 Assembly lot reduction of tinBS1748-6:1960 BSI 10-1999 3 Add2to3ml of ferric chloride solution(10per cent) then ammonia solution (sp. gr.0.91) carefully, with continuous stirring, until all the preci
27、pitated copper hydroxide has dissolved, then add a further5ml of ammonia solution (sp. gr.0.91). Cautiously bring to the boil, stirring throughout this operation, place on the edge of the hot plate or transfer to a hot water-bath and leave for30minutes. Filter the warm solution through an11cm open t
28、extured paper 1)and wash the beaker and paper well with hot ammonium sulphate solution(1percent). Discard the filtrate. Dissolve the precipitate off the paper, back into the original beaker with hot hydrochloric acid(50per cent) and wash the paper well with hot water (reserve the filter paper). Add
29、ammonia solution (sp. gr.0.91) until the solution is alkaline, then add5ml in excess. Boil, then allow to stand on the edge of the hot plate, or on a hot water-bath until the precipitate settles. Filter the solution through the original paper, and wash the beaker and paper well with hot ammonium sul
30、phate solution(1per cent). Place the funnel in the neck of a500ml conical flask, marked at150ml, open out the filter paper and support it in the funnel. Transfer the precipitate from the paper into the flask by means of a jet of hot wateruse about25ml. Wash out the beaker with20ml of hot hydrochlori
31、c acid(50percent) and pour over the filter paper into the flask. Wash the beaker twice more with20ml of hydrochloric acid(50per cent) and add to the flask as before. Wash the paper thoroughly with hot hydrochloric acid(50per cent) until the volume in the flask is about150ml, then add25ml of hydrochl
32、oric acid (sp. gr.1.161.18). The paper should not contain any precipitate after this treatment. Add two drops of antimony chloride solution(2percent). Fill the reservoir of the Contat-Gckel trap with sodium hydrogen carbonate solution (saturated). Insert the rubber bung carrying the nickel coil and
33、Contat-Gckel assembly (Figure 1) into the neck of the flask and boil gently for45minutes. Cool the test solution slightly, close the outlet tube with a rubber cap and then cool to room temperature. Remove the bung, drop in a2gr pellet of potassium (or sodium) hydrogen carbonate, rinse down, then rin
34、se and remove the nickel coil. Add5ml of starch solution and titrate to a blue end-point with the standard potassium iodate/iodide solution (N/20); it is essential to maintain the test solution in gentle agitation during the titration. Correct for the blank and calculate the tin content of the sampl
35、e, using the equivalent determined on the standard potassium iodate/iodide solution. 1) Whatman No.541 is suitable.BS1748-6: 1960 BSI 389 Chiswick High Road London W4 4AL BSIBritishStandardsInstitution BSI is the independent national body responsible for preparing BritishStandards. It presents the U
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