1、BRITISH STANDARD BS 6200-3.1.6: 1991 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.1 Determination of aluminium Subsection 3.1.6 Permanent magnet alloys: volumetric methodBS6200-3.1.6:1991 This British Standard, having been prepared under the dir
2、ectionof the Iron and Steel Standards Policy Committee, waspublished under the authorityof the Standards Boardand comes into effect on 20December1991 BSI 09-1999 The following BSI references relate to the work on this standard: Committee reference ISM/18 Draft for comment91/38341 DC ISBN 0 580 20225
3、 9 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Iron and Steel Standards Policy Committee (ISM/-) to Technical Committee ISM/18, upon which the following bodies were represented: BCIRA British Steel Industry Department of Trade and In
4、dustry (Laboratory of the Government Chemist) Ferro Alloys and Metals Producers Association Ministry of Defence Amendments issued since publication Amd. No. Date CommentsBS6200-3.1.6:1991 BSI 09-1999 i Contents Page Committees responsible Inside front cover Foreword ii 1 Scope 1 2 Principle 1 3 Reag
5、ents 1 4 Apparatus 2 5 Sampling 3 6 Procedure 3 7 Calculation and expression of results 4 8 Test report 4 Figure 1 Cell for electrolysis with mercury cathode 2 Publication(s) referred to Inside back coverBS6200-3.1.6:1991 ii BSI 09-1999 Foreword This Subsection of BS6200 has been prepared under the
6、direction of the Iron and Steel Standards Policy Committee and supersedes method2 for the determination of aluminium in BSI Handbook No.19, to which it is technically equivalent. BS 6200 is a multipart British Standard, covering all aspects of the sampling and analysis of iron, steel and other ferro
7、us metals. A list of contents, together with general information, is given in Part1. 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 its
8、elf confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pages i and ii, pages1 to 4, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be in
9、dicated in the amendment table on the inside front cover.BS6200-3.1.6:1991 BSI 09-1999 1 1 Scope This Subsection of BS6200 describes a volumetric method for the determination of acid soluble aluminium in permanent magnet alloys. The method is applicable to alloys containing5% to15% aluminium, 7% to3
10、5% nickel, 10% to30% cobalt, 0.5% to8% copper, up to3% titanium, up to6% niobium, all percentage by mass, and the remainder iron. NOTEThe titles of the publications referred to in this Subsection of BS6200 are listed on the inside back cover. 2 Principle Major amounts of interfering elements are rem
11、oved by mercury cathode electrolysis followed by precipitation with cupferron. Any remaining traces of interfering elements are complexed in ammoniacal tartrate-cyanide solution from which the aluminium is precipitated with quinolin-8-ol. The determination is completed by titration of the quinolin-8
12、-ol with potassium bromate and sodium thiosulfate. 3 Reagents During the analysis use only reagents of recognized analytical grade and only grade3 water as specified in BS3978. WARNING. Prepare solutions3.3 and3.4 in a fume cupboard. 3.1 Ammonia solution, density = 0.91g/mL. 3.2 Ammonia solution, =
13、0.91g/mL, diluted1+1. 3.3 Ammonium sulfide solution, = 1.01g/mL. Pass a rapid stream of hydrogen sulfide gas from a generator or cylinder through1L of ammonia solution (3.2) until the density is1.01g/mL approximately. 3.4 Ammonium sulfide wash solution. Add 5mL of ammonia solution (3.1) to950mL of w
14、ater and pass hydrogen sulfide gas from a generator or cylinder until just acid to litmus paper. Add a further5mL of ammonia solution (3.1), dilute to1L and mix. 3.5 Cupferron, 50g/L solution. Dissolve5g of cupferron (also known as N-nitroso-N-phenylhydroxylamine, ammonium salt) in water, dilute to1
15、00mL and mix. The solid reagent and its solution deteriorate in storage. Prepare this solution from fresh reagent immediately before use. 3.6 Cupferron-acid wash solution. To 900mL of water add10mL of sulfuric acid (3.21) and5mL of cupferron solution (3.5), dilute to1L and mix. Prepare this solution
16、 from fresh reagent immediately before use. 3.7 Hydrochloric acid, = 1.16g/mL to1.18g/mL. 3.8 Hydrochloric acid, = 1.16g/mL to1.18g/mL, diluted1+1. 3.9 Hydrochloric acid, = 1.16g/mL to1.18g/mL, diluted1+49. 3.10 Indigo carmine solution, 10g/L solution. Dissolve1g of indigo carmine in50mL of water, f
17、ilter, dilute to100mL and mix. 3.11 Mercury. Use clean mercury. Methods of recovering used mercury include filtration through a sintered glass funnel, and distillation of the remaining amalgam in an iron or mild steel pot still in a fume cupboard 1) . 3.12 Methyl red, 1g/L solution. Dissolve0.1g of
18、methyl red in60mL of ethanol, dilute to100mL with water and mix. 3.13 Nitric acid, = 1.42g/mL. 3.14 Potassium bromate, standard solution. Dissolve4.954g of potassium bromate, (previously dried to constant weight at105 C), and50g of potassium bromide (3.15) in water. Cool, transfer to a1L volumetric
19、flask, dilute to the mark and mix. 1mL of the solution is equivalent to0.4mg of aluminium. 3.15 Potassium bromide 3.16 Potassium cyanide, 100g/L solution. Dissolve10g of potassium cyanide in water, dilute to100mL and mix. 3.17 Potassium iodide, 200g/L solution. Dissolve20g of potassium iodide in wat
20、er, dilute to100mL and mix. 3.18 Quinolin-8-ol, 50g/L solution. Dissolve5g of quinolin-8-ol (also known as 8-hydroxyquinoline and oxine) in6mL of acetic acid, = 1.048g/mL to1.050g/mL, dilute to100mL and mix. 3.19 Sodium thiosulfate, standard solution. Dissolve44g of sodium thiosulfate, Na 2 S 2 O 3
21、.5H 2 O, in water containing0.1g of anhydrous sodium carbonate. Transfer to a1L volumetric flask, dilute to the mark and mix. 1mL of the solution is equivalent to approximately0.4mg of aluminium. 1) Methods of Analysis Committee. Mercury cathode electrolysis and its application to steel analysis. Jo
22、urnal of the Iron and Steel Institute, January 1954, 29-36.BS6200-3.1.6:1991 2 BSI 09-1999 3.20 Starch indicator, 5g/L solution. Make a suspension of0.5g of starch in10mL of water. Pour into80mL of boiling water. Cool, dilute to100mL and mix. 3.21 Sulfuric acid, = 1.84g/mL. 3.22 Sulfuric acid, dilut
23、ed1+1. To40mL of water, add cautiously50mL of sulfuric acid (3.21). Mix, cool, dilute to100mL and mix. 3.23 Sulfuric acid, diluted1+9. To400mL of water, add cautiously100mL of sulfuric acid (3.21). Mix, cool, dilute to1L and mix. 3.24 Tartaric acid, 200g/L solution. Dissolve20g of tartaric acid in w
24、ater, dilute to100mL and mix. 4 Apparatus 4.1 Ordinary laboratory apparatus 4.2 Volumetric glassware, in accordance with classA of BS846, BS1583, or BS1792, as appropriate. 4.3 Mercury cathode cell. The cell shown inFigure 1 is recommended for a test portion of1g. Figure 1 Cell for electrolysis with
25、 mercury cathodeBS6200-3.1.6:1991 BSI 09-1999 3 5 Sampling Carry out sampling in accordance with BS1837. NOTEBS 6200-2, which will supersede BS1837, is currently in preparation. On its publication this Subsection will be amended to include sampling in accordance with BS6200-2. 6 Procedure 6.1 Test p
26、ortion For aluminium contents up to10% (m/m) weigh, to the nearest0.001g, a test portion of1g. For higher aluminium contents weigh a0.5g test portion. 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 reagen
27、ts. 6.3 Determination 6.3.1 Preparation of the test solution Place the test portion in a400mL conical beaker add30mL of sulfuric acid (3.23), cover the beaker and heat gently until all solvent action ceases. Oxidize with2mL of nitric acid (3.13). Boil, dilute to100mL and filter through a paper-pulp
28、pad. Wash the beaker and pad eight times with hydrochloric acid (3.9) and twice with hot water. Cool the filtrate and transfer to a500mL volumetric flask, dilute to the mark and mix. Using a100mL volumetric flask, take a100mL aliquot, transfer to a250mL conical beaker, and evaporate to fuming. Conti
29、nue the fuming for5min, cool and dilute to50mL. Boil to dissolve salts and cool. 6.3.2 Mercury cathode electrolysis Transfer the solution to the electrolytic cell, rinsing the beaker with the minimum of water. Electrolyse the solution for1h at1.5A to2.5A. Transfer the solution to a250mL beaker, wash
30、 the cell with water, and adjust the volume to approximately100mL. Add20mL of sulfuric acid (3.22) and cool the solution to room temperature. 6.3.3 Removal of interfering elements Add cupferron solution (3.5) slowly, with stirring, until precipitation is complete as indicated by the coagulation of t
31、he precipitate; further addition of cupferron will produce only a white transient precipitate of the free base. Add1mL of excess cupferron solution, stir in a little paper-pulp, filter through a paper-pulp pad, and collect the filtrate in a400mL beaker. Wash the precipitate with cold cupferron-acid
32、wash solution (3.6) and discard the precipitate. To the filtrate add20mL of nitric acid (3.13) and evaporate to fuming. If necessary make further additions of the nitric acid and repeat the evaporation to fuming, until organic matter is destroyed. Cool, add30mL of water and heat until the salts are
33、dissolved. Dilute to70mL, add5mL of tartaric acid solution (3.24) and neutralize with ammonia solution (3.2) using methyl red indicator (3.12). Add10mL of potassium cyanide solution (3.16), heat to60 C and add25mL of ammonium sulfide solution (3.3). Digest at60 C for10min and cool. Filter through a
34、paper-pulp pad into a400mL beaker and wash with ammonium sulfide wash solution (3.4), ensuring that the final volume does not exceed200mL. 6.3.4 Separation of aluminium Heat to boiling and add quinolin-8-ol solution (3.18) dropwise from a burette, stirring throughout the addition. (An addition of8mL
35、 of quinolin-8-ol solution will precipitate10mg of aluminium, equivalent to5% (m/m) aluminium in a1g test portion.) Digest at90 C for10min, filter through a paper-pulp pad and wash with hot water. Dissolve the precipitate from the pad into a500mL stoppered flask with100mL of nearly boiling hydrochlo
36、ric acid (3.8) and wash the pad several times with hot water. Dilute the solution to approximately200mL and cool. 6.3.5 Titration of quinolin-8-ol Add three drops of indigo carmine solution (3.10) and titrate with potassium bromate solution (3.14) until the blue tint of the indicator is discharged.
37、Add three more drops of indigo carmine indicator (3.10) and continue the titration until the solution assumes a clear yellow colour, then add a further2mL of potassium bromate solution (3.14). Stopper the flask and allow to stand for5min. Remove the stopper, add10mL of potassium iodide solution (3.1
38、7), mix, and titrate with sodium thiosulfate solution (3.19) until the brown iodine colour is almost discharged. Add5mL of starch indicator solution (3.20) and continue the titration until the blue starch-iodide colour is discharged. Record the volumes of both titrants used for the test portion, and
39、 for the blank test. 6.3.6 Standardization of the sodium thiosulfate solution Transfer100mL of hydrochloric acid (3.8) to a500mL stoppered flask, dilute to200mL, and add25mL of potassium bromate solution (3.14) from a burette. Stopper the flask and allow to stand for5min.BS6200-3.1.6:1991 4 BSI 09-1
40、999 Remove the stopper, add10mL of potassium iodide solution (3.17), mix, and titrate with sodium thiosulfate solution (3.19) until the brown iodine colour is almost discharged. Add5mL of starch indicator solution (3.20) and continue the titration until the blue starch-iodide colour is discharged. R
41、ecord the volume V f , of sodium thiosulfate used. 7 Calculation and expression of results 7.1 Calculation Calculate the factor F of the sodium thiosulfate solution (3.19) from the equation: F = 25/V f where V fis the volume of sodium thiosulfate used in6.3.6. NOTEPotassium bromate (3.14) is equival
42、ent to0.4mg of aluminium per millilitre. Calculate the aluminium content Al expressed as a percentage by mass from the equation: where V 1is the volume of potassium bromate solution(3.14) used in the test portion titration (in mL); B 1is the volume of potassium bromate solution(3.14) used in the bla
43、nk titration (inmL); V 2is the volume of sodium thiosulfate solution(3.19) used in the test portion titration (in mL); B 2is the volume of sodium thiosulfate solution(3.19) used in the blank titration (inmL); m is the mass of the test portion (see6.1) (in g). 7.2 Precision This procedure has a preci
44、sion of approximately 0.15%(m/m). 8 Test report The test report shall include the following information: a) all information necessary for the identification of the sample, the laboratory and the date of analysis; b) the method used, by reference to this Subsection of BS6200; c) the results, and the
45、form in which they are expressed; d) any unusual features noted during the determination; e) any operation not specified in this British Standard or any optional operation which may have influenced the results.BS6200-3.1.6:1991 BSI 09-1999 Publication(s) referred to BS 846, Specification for burette
46、s. BS 1583, Specification for one-mark pipettes. BS 1792, Specification for one-mark volumetric flasks. BS 1837, Methods for the sampling of iron, steel, permanent magnet alloys and ferro-alloys. BS 3978, Specification for water for laboratory use. BS 6200, Sampling and analysis of iron, steel and o
47、ther ferrous metals. BS 6200-1, Introduction and contents 2) . BS 6200-2, Methods of sampling and sample preparation 3) . BSI Handbook No. 19, Methods for the sampling and analysis of iron, steel and other ferrous metals 2) . 2) Referred to in the foreword only. 3) In preparation.BS 6200-3.1.6: 1991
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