《BS 1728-16-1968.pdf》由会员分享，可在线阅读，更多相关《BS 1728-16-1968.pdf（8页珍藏版）》请在三一文库上搜索。
1、BRITISH STANDARD BS 1728-16: 1968 Method for The determination of chromium in aluminium and aluminium alloys (Photometric method) Methods for the analysis of aluminium and aluminium alloys Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1
2、728-16:1968 This British Standard, having been approved by the Non-ferrous Metals Industry Standards Committee, was published under the authority of the Executive Board on 31 December 1968 BSI 12-1999 The following BSI references relate to the work on this standard: Committee reference NFE/-/3 Draft
3、 for comment 67/13648 ISBN 0 580 00408 2 Co-operating organizations The Non-ferrous 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: Alum
4、inium Federation* Association of Bronze and Brass Founders Association of Consulting Engineers Board of Trade British Bronze and Brass Ingot Manufacturers Association British Electrical and Allied Manufacturers Association British Lead Manufacturers Association British Non-ferrous Metals Federation
5、British Non-ferrous Metals Federation High Conductivity Copper Group British Non-ferrous Metals Research Association* Copper Development Association Crown Agents for Oversea Governments and Administrations Electric Cable Makers Confederation Institute of British Foundrymen Institute of Metals Instit
6、ution of Mechanical Engineers (Automobile Division) 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, Army D
7、epartment* Ministry of Defence, Navy Department* National Brassfoundry Association Non-ferrous Metal Stockists Post Office Royal Institute of British Architects Society of Motor Manufacturers and Traders Ltd. Tin Research Institute Zinc Development Association Individual manufacturers The Government
8、 departments and 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: Association of Light Alloy Refiners and Smelters Ltd. Ministry of T
9、echnology Laboratory of the Government Chemist Individual analysts Amendments issued since publication Amd. No.DateComments Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1728-16:1968 BSI 12-1999i Contents Page Co-operating organizations
10、Inside front cover Forewordii 1Introduction1 2Apparatus1 3Solutions required1 4Sampling1 5Procedure1 6Calibration2 7Calculation2 8Notes2 Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1728-16:1968 ii BSI 12-1999 Foreword This standard ma
11、kes reference to the following British Standard: BS 1499, Sampling non-ferrous metals. BS 3978, Water for laboratory use. This method for the determination of chromium is the sixteenth of a series which will form a complete British Standard under the collective title “Methods for the analysis of alu
12、minium and aluminium alloys”, each 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 thiocyanate method); Part 4: Zinc (polarographic method); Part 5: Copper (absorptiometric method); Part 6: Iron (volu
13、metric: titanous chloride method); Part 7: Zinc (zinc oxide method); Part 8: Iron (absorptiometric 1 : 10-phenanthroline method); Part 9: Manganese (volumetric: arsenite/nitrite method); Part 10: Manganese (absorptiometric method); Part 11: Silicon (perchloric acid method); Part 12: Silicon (absorpt
14、iometric molybdenum blue method); Part 13: Titanium (absorptiometric chromotropic acid method); Part 14: Nickel (gravimetric method); Part 15: Nickel (photometric method); Part 17: Chromium (volumetric method). The preparation of this series of methods has been authorized by the Non-ferrous Metals I
15、ndustry Standards Committee as part of a general programme for the standardization of methods for the sampling 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 appreciate
16、d that they are primarily intended 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 application. Compliance with a British Standard does not of
17、itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages 1 and 2 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the am
18、endment table on the inside front cover. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1728-16:1968 BSI 12-19991 1 Introduction 1.1 Principle. The alloy is dissolved in sodium hydroxide solution, the solution is acidified, oxidized with
19、 potassium permanganate, and diphenylcarbazide solution is added to develop the colour. The optical density of the solution is then measured at about 540 nm. 1.2 Range. The method is recommended for chromium contents between 0.01 and 0.1 %. 1.3 Reproducibility. Experiments have been carried out inde
20、pendently by a number of analysts using this method. The degree of reproducibility that can be expected is shown by the following results obtained: 2 Apparatus 2.1 Class A volumetric glassware complying with the relevant British Standards shall be used throughout. 2.2 Any instrument suitable for mea
21、suring the optical density of the solution at a wavelength of 540 nm may be used together with 2 or 1 cm cells. Alternatively, when a filter photometer with two balanced photo-cells is used, the following conditions have been found suitable: Mercury vapour lamp; Ilford 605 or equivalent filter; 2 or
22、 1 cm cells. 3 Solutions required All reagents shall be of the highest purity obtainable and either distilled or demineralized water complying with BS 39781) shall be used throughout. Standard chromium (1.0 ml N 0.010 mg of chromium). Dissolve 2.8290 g of potassium dichromate (previously dried to co
23、nstant weight at 150 C) in water, acidify with 5 ml of sulphuric acid (50 %) and add sulphurous acid in excess. Boil for 15 minutes to remove excess of sulphur dioxide, cool, transfer to a 1 litre volumetric flask, dilute to the mark and mix. Transfer 10 ml of this solution to a 1 litre volumetric f
24、lask, dilute to the mark and mix. Diphenylcarbazide (0.1 % w/v). Dissolve 0.10 g of 1, 5-diphenylcarbazide (Note 8.1) in 5 ml of glacial acetic acid, dilute to 100 ml and mix. This solution should be freshly prepared. Ammonium ferric sulphate (0.43 % w/v). Dissolve 4.3 g of ammonium ferric sulphate
25、(NH4)2SO4.Fe2(SO4)3.24H2O in water, add 5 ml of sulphuric acid (50 %), dilute to 1 litre and mix. Phosphoric acid (10 % v/v). Dilute 100 ml of orthophosphoric acid (sp. gr. 1.75) to 1 litre and mix. Potassium permanganate (0.3 % w/v). Dissolve 0.3 g of potassium permanganate in water, dilute to 100
26、ml and mix. Sodium hydroxide (20 % w/v). Dissolve 200 g of sodium hydroxide in water, dilute to 1 litre and mix. Sulphuric acid (50 % v/v). To 400 ml of water add cautiously 500 ml of sulphuric acid (sp. gr. 1.84). Mix, cool, dilute to 1 litre and mix. Sulphurous acid. Pass sulphur dioxide gas into
27、1 litre of water until a saturated solution is obtained. 4 Sampling Recommended methods for obtaining a suitable sample for the analytical procedure given below are described in BS 1499, “Sampling non-ferrous metals”. 5 Procedure 5.1 Weigh 0.10 g of sample and transfer to a 150 ml squat beaker. Add
28、2 ml of sodium hydroxide solution (20 %). 5.2 Simultaneously carry a blank determination through the procedure using the same quantities of reagents. 5.3 When solution is complete, add 1 ml of ammonium ferric sulphate solution (0.43 %), dilute to 10 ml and boil for 12 minutes. Add 3 ml of sulphuric
29、acid (50 %), 1 ml of phosphoric acid (10 %) and 3 drops of nitric acid (sp. gr. 1.42) and warm to complete solution. Filter through a hardened paper2) if necessary. Chromium contentStandard deviation % 0.026 0.046 0.109 % 0.002 0 0.003 0 0.003 8 1) BS 3978, “Water for laboratory use”. 2) Whatman No.
30、 540 is suitable. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1728-16:1968 2 BSI 12-1999 5.4 Cool, dilute to 40 ml, add 1 ml of potassium permanganate solution (0.3 %) and boil for 5 minutes. Dilute to 60 ml with hot water, add 2.0 ml
31、 of hydrochloric acid (sp. gr. 1.161.18), then boil for 5 minutes. 5.5 Cool (Note 8.2), transfer to a 100 ml volumetric flask, dilute to about 90 ml, then add 10 ml of diphenylcarbazide solution (0.1 %), dilute to the mark and mix. 5.6 Measure the optical density within 5 minutes using the condition
32、s specified under “Apparatus”. For chromium contents up to 0.05 % use a 2 cm cell and for higher contents use a 1 cm cell. 6 Calibration 6.1 Into a series of 150 ml squat beakers, transfer amounts of standard chromium solution (1 ml N 0.010 mg of chromium) to cover the range 00.08 mg of chromium (2
33、cm cell) or 00.16 mg of chromium (1 cm cell). Continue from 5.3 of the Procedure. 6.2 Deduct the blank on the reagents from the gross optical density and prepare a calibration graph by plotting the net values against the nominal chromium contents of the solutions. 7 Calculation Convert the optical d
34、ensity readings for the test sample to percentage chromium by means of the calibration graph. 8 Notes 8.1 The reagent should be pinkish in colour and any material which is buff in colour should not be used. The most satisfactory criterion of the quality of the reagent is its melting point which shou
35、ld be between 175 and 177 C. 8.2 If cloudy, filter the solution. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI blank Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 1728-16: 196
36、8 BSI 389 Chiswick High Road London W4 4AL BSI British Standards Institution BSI is the independent national body responsible for preparing British Standards. It presents the UK view on standards in Europe and at the international level. It is incorporated by Royal Charter. Revisions British Standar
37、ds are updated by amendment or revision. Users of British Standards should make sure that they possess the latest amendments or editions. It is the constant aim of BSI to improve the quality of our products and services. We would be grateful if anyone finding an inaccuracy or ambiguity while using t
38、his British Standard would inform the Secretary of the technical committee responsible, the identity of which can be found on the inside front cover. Tel: 020 8996 9000. Fax: 020 8996 7400. BSI offers members an individual updating service called PLUS which ensures that subscribers automatically rec
39、eive the latest editions of standards. Buying standards Orders for all BSI, international and foreign standards publications should be addressed to Customer Services. Tel: 020 8996 9001. Fax: 020 8996 7001. In response to orders for international standards, it is BSI policy to supply the BSI impleme
40、ntation of those that have been published as British Standards, unless otherwise requested. Information on standards BSI provides a wide range of information on national, European and international standards through its Library and its Technical Help to Exporters Service. Various BSI electronic info
41、rmation services are also available which give details on all its products and services. Contact the Information Centre. Tel: 020 8996 7111. Fax: 020 8996 7048. Subscribing members of BSI are kept up to date with standards developments and receive substantial discounts on the purchase price of stand
42、ards. For details of these and other benefits contact Membership Administration. Tel: 020 8996 7002. Fax: 020 8996 7001. Copyright Copyright subsists in all BSI publications. BSI also holds the copyright, in the UK, of the publications of the international standardization bodies. Except as permitted
43、 under the Copyright, Designs and Patents Act 1988 no extract may be reproduced, stored in a retrieval system or transmitted in any form or by any means electronic, photocopying, recording or otherwise without prior written permission from BSI. This does not preclude the free use, in the course of i
44、mplementing the standard, of necessary details such as symbols, and size, type or grade designations. If these details are to be used for any other purpose than implementation then the prior written permission of BSI must be obtained. If permission is granted, the terms may include royalty payments or a licensing agreement. Details and advice can be obtained from the Copyright Manager. Tel: 020 8996 7070. Licensed Copy: sheffieldun sheffieldun, na, Fri Nov 24 08:09:30 GMT+00:00 2006, Uncontrolled Copy, (c) BSI