1、BRITISH STANDARD BS 6200-3.12.5: 1986 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.12 Determination of copper Subsection 3.12.5 Permanent magnet alloys: volumetric method UDC 669.1:543.24:546.56BS 6200-3.12.5:1986 This British Standard, having b
2、een prepared under the direction of the Iron and Steel Standards Committee, was published under the authority of the Board of BSI and comes into effect on 30September 1986 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference ISM/18 Draft for comment 85/36
3、504 DC ISBN 0 580 15278 2 Foreword This Subsection of BS6200 has been prepared under the direction of the Iron and Steel Standards Committee. It supersedes method 4 for the determination of copper in BSI Handbook No.19, to which it is technically equivalent. BS 6200 is a multipart British Standard c
4、overing all aspects of the sampling and analysis of iron, steel and other ferrous metals. A list of contents, together with general information, will be given in Part 1, to be published in due course. A British Standard does not purport to include all the necessary provisions of a contract. Users of
5、 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, pages i and ii, pages1 and2, an inside back cover and a back
6、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. Amendments issued since publication Amd. No. Date CommentsBS 6200-3.12.5:1986 BSI 09-1999 i Contents Page Foreword Inside fron
7、t cover 1 Scope 1 2 Principle 1 3 Reagents 1 4 Apparatus 1 5 Sampling 1 6 Procedure 2 7 Calculation and expression of results 2 8 Test report 2 Publications referred to Inside back coverii blankBS 6200-3.12.5:1986 BSI 09-1999 1 1 Scope This Subsection of BS6200 describes a volumetric method for the
8、determination of copper in permanent magnet alloys. The method is applicable to the determination of copper in permanent magnet alloys containing5%m/m to15%m/m aluminium,7%m/m to35%m/m nickel, 10%m/m to30%m/m cobalt, 0.5%m/m to8%m/m copper, up to3%m/m titanium, upto6%m/m niobium and the remainder ir
9、on. NOTEThe titles of the publications referred to in this Subsection of BS6200 are listed on the inside back cover. 2 Principle In an oxidized sulphuric acid solution of the sample, iron is reduced with sulphurous acid. Cupric sulphide is precipitated with hydrogen sulphide, filtered off, washed an
10、d ignited. The residue is dissolved in acid and the determination completed volumetrically by releasing the iodine equivalent of the copper with potassium iodide and titrating with sodium thiosulphate. 3 Reagents During the analysis, use only reagents of recognized analytical reagent grade and only
11、distilled water or water of equivalent purity, free from copper. 3.1 Acetic acid, glacial, density ( ) 1.048 g/mL to1.050 g/mL. 3.2 Ammonia solution, 0.91g/mL, diluted1+1. 3.3 Copper, standard solution corresponding to2mg of copper per mL. Dissolve 2.000g of high purity copper in30mL of nitric acid
12、(3.6). Boil to remove nitrous fumes and cool. Transfer to a 1L volumetric flask, dilute to the mark and mix. 3.4 Hydrogen sulphide-sulphuric acid wash To 900mL of water add 10mL of sulphuric acid(3.12) and dilute to 1L. Then pass a rapid stream of hydrogen sulphide gas from a generator or cylinder t
13、hrough the solution for not less than10min. 3.5 Nitric acid, 1.42g/mL. 3.6 Nitric acid, 1.42g/mL, diluted 2+3. 3.7 Potassium iodide, 600g/L solution. Dissolve60g of potassium iodide in water, dilute to100mL and mix. 3.8 Potassium thiocyanate, 200g/L solution. Dissolve200g of potassium thiocyanate in
14、 water, dilute to1L and mix. 3.9 Sodium fluoride 3.10 Sodium thiosulphate, 4g/L solution, corresponding to1mg of copper permL. 3.10.1 Preparation. Dissolve4.0g of sodium thiosulphate pentahydrate (Na 2 S 2O 3 .5H 2 O) in water containing 0.1g of sodium carbonate. Transfer to a 1 L volumetric flask,
15、dilute to the mark and mix. 3.10.2 Standardization. Transfer25mL of copper solution (3.3) to a250mL conical beaker, add10mL of sulphuric acid (3.13) and evaporate to fuming. Cool, add with care10mL of water, 0.5g of sodium fluoride (3.9) and, when dissolved, add ammonia solution (3.2) until the blue
16、 colour of the cuprammonium complex is fully developed. Cool, acidify with glacial acetic acid (3.1) and add 1mL in excess. Cool, add5mL of potassium iodide solution (3.7) and titrate with sodium thiosulphate solution(3.10.1) until the brown iodine colour is almost discharged. Add5mL of starch indic
17、ator(3.11),10mL of potassium thiocyanate solution (3.8) and continue the titration until the blue starch-iodide colour is just discharged. Record the copper equivalent of the sodium thiosulphate solution in mg per mL. 3.11 Starch, 5 g/L solution. Make a suspension of0.5g of starch in10mL of water. A
18、dd to90mL of boiling water. Cool, dilute to100mL and mix. 3.12 Sulphuric acid, 1.84g/mL. 3.13 Sulphuric acid, 1.84g/mL, diluted 3+17. To 400mL of water add cautiously 150mL of sulphuric acid (3.12). Mix, cool, dilute to 1 L and mix. 3.14 Sulphuric acid, 1.84 g/mL, diluted 1+49. To 400mL of water add
19、 cautiously20mL of sulphuric acid (3.12). Mix, cool, dilute to 1L and mix. 3.15 Sulphurous acid Pass sulphur dioxide gas into 1L of water until a saturated solution is obtained. 4 Apparatus Use ordinary laboratory apparatus. Use only volumetric glassware in accordance with class A of BS846, BS1583 o
20、r BS1792, as appropriate. 5 Sampling Sampling shall be carried out in accordance with BS1837.BS 6200-3.12.5:1986 2 BSI 09-1999 NOTEBS 6200-2 “Methods of sampling and sample preparation”, which will supersede BS1837, is currently in preparation. On its publication, this Subsection will be amended to
21、include a requirement to sample in accordance with BS 6200-2. 6 Procedure 6.1 Test portion Weigh, to the nearest0.001g, a test portion in accordance with the following: a) 2 g for samples with presumed copper contents between0.5%m/m and2%m/m; b) 1 g for samples with presumed copper contents between2
22、%m/m and5%m/m; c) 0.5 g for samples with presumed copper contents between5%m/m and8%m/m. 6.2 Blank test In parallel with the determination and following the same procedure, carry out a blank test using the same quantities of all the reagents. 6.3 Determination Place the test portion in a650mL conica
23、l beaker, add50mL of sulphuric acid (3.13), cover the beaker and heat until solvent action ceases. Oxidize with nitric acid (3.5) and evaporate to fuming. Cool, dilute to200mL and heat until the soluble salts are dissolved. Add30mL of the sulphurous acid (3.15), boil until the sulphur dioxide is rem
24、oved and cool. Filter through a paper-pulp pad into a650mL conical beaker and wash the filter and precipitate with sulphuric acid (3.14). Heat the filtrate to about50 C and pass a rapid stream of hydrogen sulphide gas from a generator or cylinder through the solution for10min. Filter through a paper
25、-pulp pad and wash with the hydrogen sulphide-sulphuric acid wash solution(3.4). Transfer the filter and precipitate to a silica or platinum crucible and ignite at a temperature not exceeding550 C. Transfer the residue to a250mL conical beaker, add10mL of nitric acid (3.5) and warm until the residue
26、 is dissolved. Add10mL of sulphuric acid (3.13) and evaporate to fuming. Cool, add10mL of water,0.5g of sodium fluoride (3.9) and, when dissolved, add ammonia solution (3.2) until the blue colour of the cuprammonium complex is fully developed. Cool, acidify with glacial acetic acid (3.1) and add 1mL
27、 excess. NOTENo colour will develop in the blank test; changes in acidity should be detected by removing a drop of solution and testing it with litmus paper. Cool, add5mL of potassium iodide solution (3.7) and titrate with sodium thiosulphate solution (3.10) until the brown iodine colour is almost d
28、ischarged. Add5mL of starch indicator (3.11),10mL of potassium thiocyanate solution (3.8) and continue the titration until the blue starch-iodide colour is just discharged. 7 Calculation and expression of results 7.1 Calculation Calculate the copper content, expressed as a percentage by mass, from t
29、he equation Copper content = where 7.2 Precision Replicate agreements in accordance with the following may be expected from this method: a) 0.02% for copper contents of 0.5 % m/m; b) 0.05% for copper contents of 4 % m/m; c) 0.10% for copper contents of 8% m/m. 8 Test report The test report shall con
30、tain the following information: a) identification of the sample; b) the method of analysis used, by reference to this Subsection of BS6200; c) the results obtained and the form in which they are expressed; d) any particular details noted during the determination; e) any operations not specified in t
31、his standard or any optional operations which may have influenced the results. V is the volume (in mL) of sodium thiosulphate solution (3.10) required for the test portion; V 0 is the volume (in mL) of sodium thiosulphate solution required for the blank test (6.2); m 1 is the copper equivalent (in m
32、g/mL) of the sodium thiosulphate solution (3.10.2); m is the mass (in g) of the test portion (6.1). VV 0 () m 1 10m -BS 6200-3.12.5:1986 BSI 09-1999 Publications referred to BS 846, Specification for burettes. BS 1583, Specification for one-mark pipettes. BS 1792, Specification for one-mark volumetr
33、ic flasks. BS 1837, Methods for the sampling of iron, steel, permanent magnet alloys and ferro-alloys. BSI Handbook No. 19, Methods for the sampling and analysis of iron, steel and other ferrous metals 1) . 1) Referred to in the foreword only.BS 6200-3.12.5: 1986 BSI 389 Chiswick High Road London W4
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