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1、BRITISH STANDARD BS 6200-3.12.4: 1986 Sampling and analysis of iron, steel and other ferrous metals Part 3: Methods of analysis Section 3.12 Determination of copper Subsection 3.12.4 Cast iron: volumetric method UDC 669.1:543.24:546.56 Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:59:03
2、GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6200-3.12.4:1986 This British Standard, having been 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 September 1986 BSI 09-1999 The following BSI refere
3、nces relate to the work on this standard: Committee reference ISM/18 Draft for comment 85/36503 DC ISBN 0 580 15280 4 Foreword This Subsection of BS 6200 has been prepared under the direction of the Iron and Steel Standards Committee. It supersedes method 5 for the determination of copper in BSI Han
4、dbook 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 ferrous metals. A list of contents, together with general information, will be given in Part 1, to be published in due course. A Bri
5、tish 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 itself confer immunity from legal obligations. Summary of pages This document comprises a fro
6、nt cover, an inside front cover, pages i and ii, pages 1 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 indicated in the amendment table on the inside front cover. Amendments issued since publica
7、tion Amd. No.Date of issueComments Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:59:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6200-3.12.4:1986 BSI 09-1999i Contents Page ForewordInside front cover 1Scope1 2Principle1 3Reagents1 4Apparatus1 5Sampling1 6Procedure1 7Calculation and e
8、xpression of results3 8Test report3 Table 1 Precision data3 Publications referred toInside back cover Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:59:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI ii blank Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:59:03 GMT+00:00 2006, Un
9、controlled Copy, (c) BSI BS 6200-3.12.4:1986 BSI 09-19991 1 Scope This Subsection of BS 6200 describes a volumetric method for the determination of copper in cast iron. The method is applicable to copper contents exceeding 0.1 % m/m. NOTEThe titles of the publications referred to in this Subsection
10、of BS 6200 are listed on the inside back cover. 2 Principle After the removal of iron by extraction with isobutyl acetate, copper is converted to its diethyldithiocarbamate complex in ammoniacal citrate solution containing ethylenediaminetetra-acetic acid disodium salt (EDTA Na2). It is then extract
11、ed into chloroform. Organic matter is destroyed and copper is titrated with EDTA Na2. 3 Reagents During the analysis, use only reagents of recognized analytical reagent grade and only distilled water or water of equivalent purity, free from copper. 3.1 Ammonia solution, density () 0.91 g/mL. 3.2 Amm
12、onia solution, 0.91 g/mL, diluted 1 + 1. 3.3 Triammonium citrate, 500 g/L solution. Dissolve 500 g of citric acid (H8C6O7.H2O) in 500 mL of ammonia solution (3.1). Cool, dilute to 1 L and mix. 3.4 Chloroform 3.5 Copper, standard solution, corresponding to 1 mg copper per mL. Dissolve 1.000 g of high
13、 purity copper in 30 mL of nitric acid (3.12). Boil to remove nitrous fumes and cool. Transfer to a 1 L volumetric flask, dilute to the mark and mix. 3.6 Ethylenediaminetetra-acetic acid disodium salt (EDTA Na2). 3.7 Ethylenediaminetetra-acetic acid disodium salt standard solution, corresponding to
14、approximately 1 mg of copper per mL. 3.7.1 Preparation. Dissolve 5.86 g of EDTA Na2 in water. Transfer to a 1 L volumetric flask, dilute to the mark and mix. 3.7.2 Standardization. Transfer 10.0 mL of copper solution (3.5) to a 400 mL conical beaker and add 1 mL of perchloric acid (3.13). Evaporate
15、just to fumes of perchloric acid, cool and dissolve in 50 mL of water. Add 1 mL murexide indicator (3.10) followed by ammonia solution (3.2) dropwise until the pH of the solution, as indicated by close-range indicator paper, is between 7 and 9. Titrate with EDTA Na2 standard solution (3.7.1) to a pu
16、rple end-point, which does not change on further addition of EDTA Na2 standard solution. Record the copper equivalent of the EDTA Na2 standard solution in mg per mL. 3.8 Hydrochloric acid, 1.16 g/mL to 1.19 g/mL. 3.9 Isobutyl acetate 3.10 Murexide, 0.5 g/L solution in ethanediol. Dissolve 0.05 g of
17、murexide in 100 mL of ethanediol. 3.11 Nitric acid, 1.42 g/mL. 3.12 Nitric acid, 1.42 g/mL, diluted 2 + 3. 3.13 Perchloric acid, 1.54 g/mL. 3.14 Sodium diethyldithiocarbamate, 100 g/L solution. Dissolve 10 g of sodium diethyldithiocarbamate in water, dilute to 100 mL and mix. 4 Apparatus Use ordinar
18、y laboratory apparatus. Use only volumetric glassware in accordance with class A of BS 846, BS 1583 or BS 1792, as appropriate. 5 Sampling Sampling shall be carried out in accordance with BS 1837. NOTEBS 6200-2 “Methods of sampling and sample preparation”, which will supersede BS 1837, is currently
19、in preparation. On its publication, this Subsection will be amended to include a requirement to sample in accordance with BS 6200-2. 6 Procedure 6.1 Test portion Weigh, to the nearest 0.001 g, a test portion in accordance with the following: a) 5 g, for samples with presumed copper contents up to 0.
20、5 % m/m; b) 2 g, for samples with presumed copper contents between 0.5 % m/m and 1.0 % m/m; c) 1 g, for samples with presumed copper contents above 1 % m/m. Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:59:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6200-3.12.4:1986 2 BSI 09-1999 6.
21、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 a dry 400 mL squat beaker and, depending on its mass, add a mixture of hydrochloric acid (3.8) and nitri
22、c acid (3.11) in accordance with the following: a) for a 5 g test portion, 50 mL of hydrochloric acid and 15 mL nitric acid; b) for a 2 g test portion, 35 mL of hydrochloric acid and 10 mL nitric acid; c) for a 1 g test portion, 20 mL of hydrochloric acid and 10 mL nitric acid. Add the premixed acid
23、s in small portions (about 10 mL at a time), waiting until the vigorous reaction subsides before adding the next portion and covering the beaker after each addition. Do not apply heat. NOTE 1Most cast irons will dissolve readily without the application of heat, and usually any apparent drillings rem
24、aining 5 min after the addition of acid are pseudomorphs of graphite and silica. A gentle effervescence is not evidence that the sample is still dissolving, but is more likely to be due to the oxidation of hydrochloric acid by nitric acid. For alloy irons, in particular high chromium irons, heating
25、may be necessary. This should be kept to a minimum and prolonged boiling avoided as this leads to loss of hydrochloric acid and decreased efficiency of the isobutyl acetate extraction. When the test portion has dissolved, cool and then filter through a glass filter or dry glass wool pad into a dry 2
26、50 mL conical separating funnel; wash the beaker and the filter with hydrochloric acid (3.8) from a polyethylene wash bottle. For a 5 g test portion, adjust the volume to about 90 mL with hydrochloric acid (3.8) and add 150 mL of isobutyl acetate (3.9). For a 2 g test portion, adjust the volume to a
27、bout 75 mL and add 100 mL of isobutyl acetate (3.9). For a 1 g test portion, adjust the volume to about 60 mL and add 60 mL of isobutyl acetate (3.9). Shake vigorously for 30 s, allow the two layers to separate and run the lower (aqueous) layer into a 400 mL squat beaker. Add 10 mL of hydrochloric a
28、cid (3.8) to the isobutyl acetate in the separating funnel, shake again and transfer the lower (aqueous) layer to the 400 mL beaker. Repeat this procedure with two further 10 mL portions of hydrochloric acid (3.8). Allow the separating funnel to stand for 2 min, then run into the beaker the small am
29、ount of acid which has drained down, allowing the interface to travel to the bottom of the stopcock bore. Rinse the stem of the separating funnel with water into the beaker. Discard the organic phase. Evaporate the solution to about 40 mL, add 5 mL of nitric acid (3.11) and 10 mL of perchloric acid
30、(3.13) and then evaporate to fumes of perchloric acid. Continue fuming for 3 min with the beaker covered. Cool slightly, add 35 mL of water and heat to boiling, then cool. If the sample contains more than 2.5 % m/m of copper, transfer to a 100 mL volumetric flask, dilute to the mark and mix. Take an
31、 aliquot containing not more than 25 mg of copper, dilute if necessary to a volume of about 50 mL and continue as follows, in common with all other test portions. Add 15 mL of the triammonium citrate solution (3.3), 2 g of EDTA Na2 (3.6), followed by ammonia solution (3.1) dropwise until the solutio
32、n is alkaline to litmus paper. Then add 5 mL in excess. Filter through a paper-pulp pad into a 250 mL conical separating funnel and wash with cold water. Add 10 mL of sodium diethyldithiocarbamate solution (3.14) and 25 mL of chloroform (3.4). Shake vigorously, allow the two layers to separate and r
33、un the lower (chloroform) layer into a 400 mL conical beaker. Add 10 mL of chloroform (3.4) to the separating funnel and shake again, running the chloroform layer into the conical beaker. Wash with two further 10 mL portions of chloroform (3.4) and combine all the chloroform extracts. Discard the aq
34、ueous phase. Evaporate the chloroform phase just to dryness. Add cautiously 5 mL of nitric acid (3.11), followed by 10 mL of hydrochloric acid (3.8) and 1 mL of perchloric acid (3.13). NOTE 2This and all subsequent reagent additions should be made by means of a pipette or burette. Evaporate to fumes
35、 of perchloric acid, cool and dissolve in 50 mL of water. Add 1 mL of murexide indicator (3.10) followed by ammonia solution (3.2) dropwise until the pH of the solution, as indicated by suitable close-range indicator paper, is between 7 and 9. Titrate with EDTA Na2 standard solution (3.7) to a purpl
36、e endpoint which does not change on further addition of EDTA Na2 standard solution (3.7). Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:59:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6200-3.12.4:1986 BSI 09-19993 7 Calculation and expression of results 7.1 Calculation Calculate the
37、copper content, expressed as a percentage by mass, from the equation where 7.2 Precision A planned trial of this method was carried out by 10 analysts, each from a different laboratory: three tests were carried out by each analyst on each of four samples. From the results obtained, the 95 % confiden
38、ce limits (2s) have been calculated in accordance with BS 5497-1 and are given in Table 1. Table 1 Precision data The difference between two single results found on identical material by one analyst using the same apparatus within a short time interval will exceed the repeatability, r, not more than
39、 once in 20 cases in the normal and correct operation of the method. The difference between two single and independent results found by two operators working in different laboratories on identical test material will exceed the reproducibility, R, on average, not more than once in 20 cases in the nor
40、mal and correct operation of the method. 8 Test report The test report shall contain the following information: a) identification of the sample; b) the method of analysis used, by reference to this Subsection of BS 6200; c) the results obtained and the form in which they are expressed; d) any partic
41、ular details noted during the determination; e) any operations not specified in this standard or any optional operations which may have influenced the results. Vis the volume (in mL) of EDTA Na2 standard solution (3.7) used; V0is the volume (in mL) of EDTA Na2 standard solution required for the blan
42、k test (6.2); m1is the copper equivalent (in mg/mL) of the EDTA Na2 standard solution (3.7.2); mis the mass (in g) of the test portion (6.1). Alloy typeCopper content Repeatability, r Reproducibility, R % m/m White cast iron 0.130.0080.014 Grey cast iron0.490.0190.040 Grey cast iron1.470.0290.086 13
43、 % m/m Ni, 4 % m/m Cr austenitic cast iron 5.030.0380.122 Copper content VV0() m1 10m - -= Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:59:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI 4 blank Licensed Copy: sheffieldun sheffieldun, na, Wed Dec 06 14:59:03 GMT+00:00 2006, Uncontrolled C
44、opy, (c) BSI BS 6200-3.12.4:1986 BSI 09-1999 Publications referred to BS 846, Specification for burettes. BS 1583, Specification for one-mark pipettes. BS 1792, Specification for one-mark volumetric flasks. BS 1837, Methods for the sampling of iron, steel, permanent magnet alloys and ferro-alloys. B
45、S 5497, Precision of test methods. BS 5497-1, Guide for the determination of repeatability and reproducibility for a standard test method. BSI Handbook No. 19, Methods for the sampling and analysis of iron, steel and other ferrous metals1). 1) Referred to in the foreword only. Licensed Copy: sheffie
46、ldun sheffieldun, na, Wed Dec 06 14:59:03 GMT+00:00 2006, Uncontrolled Copy, (c) BSI BS 6200-3.12.4: 1986 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
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