BS 7317-5-1990 Methods for analysis of high purity copper cathode Cu-CATH-1 - Method for determination of sulphur by hydrogen sulphide evolution and spectrophotometry《高纯度铜阴极Cu-CATH.pdf

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1、BRITISH STANDARD BS7317-5:1990Methods forAnalysis of high purity copper cathodeCu-CATH-1 Part 5: Method for determination of sulphur by hydrogen sulphide evolution and spectrophotometryUDC 669.3.015.4:543.422.062:546.22BS7317-5:1990This BritishStandard, having been prepared under the directionof the

2、 Non-ferrous Metals Standards Policy Committee, was published underthe authorityof the Board ofBSI and comesinto effect on31July1990 BSI01-2000The following BSI references relate to the work on this standard:Committee reference NFM/34Draft for Development DD95-5ISBN 0 580 18464 1Committees responsib

3、le for this BritishStandardThe preparation of this BritishStandard was entrusted by the Non-ferrous Metals Standards Policy Committee (NFM/-) to Technical Committee NFM/34, upon which the following bodies were represented:British Bathroom CouncilBritish Cable Makers ConfederationBritish Gas plcBriti

4、sh Malleable Tube Fittings AssociationBritish Non-ferrous Metals FederationBritish Valve and Actuator Manufacturers AssociationCopper Development AssociationLondon Metal ExchangeNon-ferrous Metal StockistsSociety of British Aerospace Companies Ltd.Transmission and Distribution Association (BEAMA Ltd

5、.)Coopted membersThe following bodies were also represented in the drafting of the standard, through subcommittees and panels:BNF Metals Technology CentreBritish Bronze and Brass Ingot Manufacturers AssociationBureau of Analysed Samples Ltd.Copper Smelters and Refiners AssociationMinistry of Defence

6、Amendments issued since publicationAmd. No. Date of issue CommentsBS7317-5:1990 BSI 01-2000 iContentsPageCommittees responsible Inside front coverForeword ii1 Scope 12 Principle 13 Reagents 14 Apparatus 15 Procedure 46 Calculation and expression of results 57 Repeatability and reproducibility 58 Tes

7、t report 5Figure 1 Reducing acid mixture purifying apparatus 2Figure 2 Reflux apparatus for evolving hydrogen sulphide 3Table 1 Repeatability and reproducibility of results 5Publications referred to Inside back coverBS7317-5:1990ii BSI 01-2000ForewordBS7317 has been prepared under the direction of t

8、he Non-ferrous Metals Standards Policy Committee. It describes methods for the determination of impurity elements in high purity copper cathode designated Cu-CATH-1, each method being published as a separate Part. The methods are based on those previously issued in the Draft for Development series D

9、D95-1 to DD95-7. The information and experience gained from the practical application of DD95 have been taken into account in the methods in BS7317.This Part of BS7317 supersedes DD95-5:1986, which is withdrawn. It is one of a series of methods in BS7317, the others being as follows: Part1: Method f

10、or determination of cadmium, manganese and silver (screening procedure for chromium, cobalt, iron, nickel and zinc) by atomic absorption spectrophotometry; Part2: Method for determination of chromium, cobalt, iron, nickel and zinc by discrete volume nebulization atomic absorption spectrophotometry;

11、Part3: Method for determination of antimony, arsenic, bismuth, selenium, tellurium and tin by hydride generation and atomic absorption spectrophotometry; Part4: Method for determination of antimony, arsenic, bismuth, lead, selenium, tellurium and tin by electrothermal atomization atomic absorption s

12、pectrophotometry; Part6: Method for determination of phosphorus and silicon by spectrophotometry; Part7: Method for determination of lead by lanthanum hydroxide separation and atomic absorption spectrophotometry.The atomic absorption spectrophotometric procedures in Parts1 and2 are complementary. A

13、sample solution concentration found to be satisfactory for nebulizers in standard atomic absorptiometers was20g/L. At this concentration the precision obtainable, using the method described in Part1, is only sufficient to allow the determination of cadmium, manganese and silver. Results would be obt

14、ained for chromium, cobalt, iron, nickel and zinc that would prove useful in detecting impurities grossly in excess of the requirements for chemical composition specified in BS6017 for Cu-CATH-1 and would give a guide to the levels to be determined by Part2.The discrete volume nebulization procedure

15、 in Part2 was developed to enable a higher equivalent sample solution concentration of100g/L to be used without nebulizer blockage. The method involves no chemical separation, which can give rise to contamination problems, and the extra sensitivity obtained enables the impurities to be determined to

16、 an adequate accuracy for the requirements for chemical composition specified in BS6017 for Cu-CATH-1.Parts1 and2 essentially cover the same impurities. Part4 covers the electrothermal atomization atomic absorption spectrophotometric method and is recommended where the facility is available. Parts1,

17、2,3 and7 are included for use where the electrothermal atomization equipment is not available.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 no

18、t of itself confer immunity from legal obligations.Summary of pagesThis document comprises a front cover, an inside front cover, pagesi andii, pages1 to6, 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

19、indicated in the amendment table on the inside front cover.BS7317-5:1990 BSI 01-2000 11 ScopeThis Part of BS7317 describes a method for the determination of the actual amount of the impurity element sulphur present in high purity copper cathode (designated Cu-CATH-1), by hydrogen sulphide evolution

20、and spectrophotometry. It is applicable to concentrations of sulphur within the range54g/g to304g/g(0.0005%m/m to0.0030%m/m).NOTEThe titles of the publications referred to in this Part of BS7317 are listed on the inside back cover.2 PrincipleAny sulphur present in the analysis sample is reduced to h

21、ydrogen sulphide by dissolution in a reducing acid mixture containing antimony. The hydrogen sulphide is transferred into a zinc acetate solution by a stream of either nitrogen or argon and the sulphur is precipitated as zinc sulphide. The zinc sulphide is reacted, in a sulphuric acid solution, with

22、4-amino-N, N-dimethylaniline in the presence of iron(III) to produce methylene blue. The colour is measured photometrically.3 ReagentsWARNING. There are toxicity risks associated with the acid mixture (solution3.2) used in the method described in this Part of BS7317 and it is essential that reasonab

23、le precautions are taken. Check the performance and leak-tightness of the assembled apparatus.3.1 GeneralDuring the analysis, use only reagents of recognized analytical quality or of higher purity and only distilled water that has no detectable level of sulphur. Do not use deionized water.NOTEUnless

24、 otherwise stated, all solutions are aqueous solutions.3.2 Acid mixture. Mix togetherTransfer the mixture to a1L distillation flask.Boil the mixture at a temperature of113C to115C in the distillation flask using a reflux condenser (seeFigure 1), for1.5h while passing a stream of either nitrogen or a

25、rgon(3.6) at approximately10L/h. Use30mL water and5mL absorption solution(3.3) in the hydrogen sulphide trap. Allow the mixture to cool under a stream of either nitrogen or argon and transfer it to a bottle fitted with a ground glass stopper.Repeat this purification procedure once a week to eliminat

26、e any sulphur contamination that may recur.3.3 Absorption solution. Dissolve25g of zinc acetate (CH3COO)2 Zn.2H2O and6.25g of sodium acetate (CH3COONa.3H2O) in water and dilute to500mL. Filter if necessary.3.4 4-amino-N, N-dimethylaniline reagent solution. Dissolve0.5g of4-amino-N,N-dimethylaniline-

27、dihydrochloride in300mL ofwater; add100mL of sulphuric acid, 1.84g/mL. Cool and make up to500mL with water. Filter if necessary.3.5 Ammonium iron(III) sulphate solution. Dissolve12.5 of ammonium iron(III) sulphate NH4Fe(SO4)2.12H2O in approximately80mL ofwater and add2.5mL of sulphuric acid, 1.84g/m

28、L. Warm gently. Cool and dilute to approximately100mL.3.6 High purity nitrogen (or argon). Pass the nitrogen (or argon) through a gas washing bottle containing water before it enters the distillation apparatus. Lower grade nitrogen may be used if gas washing solution(3.7) is used instead of water in

29、 the gas wash bottle.Use plastics tubes to connect the pressure cylinder to glass apparatus.3.7 Gas washing solution. Dissolve10g of sodium phosphinate (NaH2PO2.H2O) and10g of pyrogallol in10mL water.3.8 Sulphur stock solution (1mg sulphur permillilitre).Dissolve2.72g of potassium sulphate (K2SO4),

30、previously dried for2h at150C, in water and make up to500mL in a volumetric flask.3.9 Sulphur standard solution (104g sulphur per millilitre). Dilute10.00mL of sulphur stock solution(3.8) with water to1000mL in a volumetric flask. Prepare immediately before use.3.10 Hydrochloric acid, 1.18g/mL,20%V/

31、V solution.3.11 Hydrofluoric acid, 1.13g/mL,2%V/V solution.3.12 Methanol4 Apparatus4.1 Spectrophotometer, equipped with20mm and40mm glass cells, suitable for measuring the optical density (absorbance) of a solution at a wavelength of665nm.300mL hydriodic acid, 1.7g/mL;200mL formic acid, 1.22g/mL;50g

32、 sodium phosphinatea (NaH2PO2.H2O) and0.2g antimony trioxide.a Commonly known as “sodium hypophosphite”.BS7317-5:19902 BSI 01-2000NOTEConical ground glass joints comply with BS572.Figure 1 Reducing acid mixture purifying apparatusBS7317-5:1990 BSI 01-2000 3NOTE 1Conical ground glass joints comply wi

33、th BS572.NOTE 2Spherical ground joint complies with BS2761.Figure 2 Reflux apparatus for evolving hydrogen sulphideBS7317-5:19904 BSI 01-20004.2 Distillation apparatus, comprising:a) a reducing mixture purifying apparatus, as shown in Figure 1; andb) a reflux apparatus for evolving hydrogen sulphide

34、, as shown in Figure 2.Use apparatus with polytetrafluoroethylene (PTFE) sleeves on all conical joints.4.3 Flowmeter and gas washing bottle, for the nitrogen or argon gas(3.6).4.4 Ordinary laboratory equipment5 Procedure5.1 Preparation of apparatus5.1.1 Reflux condenser. Ensure that the reflux conde

35、nser is free from grease by cleaning with the following reagents in sequence:methanol(3.12)hydrochloric acid solution(3.10)watermethanol(3.12)The condenser is sufficiently clean when no drops of liquid adhere to the glass surfaces after this treatment. Whenever the cleaning operation is repeated, us

36、e hydrofluoric acid solution(3.11) before the reagents in the above sequence.5.1.2 Distillation apparatus. Clean the distillation apparatus by boiling out with25mL of the acid mixture(3.2) under the same conditions as are to be used during the actual sulphur determinations (see5.5). Continue the cle

37、aning operation until the blank value obtained is equal to that of the reagent blank (see5.2). Empty the apparatus.Clean the absorption tube (seeFigure 2) after each analysis by flushing with water three times, followed by methanol once.To avoid any contamination of the distillation apparatus, when

38、it is not to be used for a long time, thoroughly flush the apparatus with either nitrogen or argon and close the absorption tube with a cap. After a short break in the analytical work, it is sufficient to flush the apparatus with a gentle stream of either nitrogen or argon.5.1.3 Ground glass joint o

39、f the absorption tube. Lightly grease the spherical joint of the absorption tube with silicone grease.5.2 Verification of reagent purityTransfer30mL of water,5mL of absorption solution(3.3),5mL of4-amino-N,N-dimethylaniline reagent solution(3.4) and1mL of ammonium iron(III) sulphate solution(3.5) to

40、 a50mL volumetric flask.Make up to the mark with water, mix well, allow to stand out of direct sunlight for10min and measure the absorbance value at a wavelength of665nm using a40mm cell. If the absorbance value is greater than0.01, reject the reagents(3.3 to3.5) and reprepare fresh reagents.NOTEThe

41、 colour is stable for up to6h if stored out of direct sunlight.5.3 Test portionsTake sawings, millings or drillings from the analysis sample.NOTESawings are preferred but millings or drillings, provided that they are of similar fineness, are also suitable.5.4 Calibration5.4.1 Clean the distillation

42、apparatus as described in5.1.2. Pour30mL of the acid mixture(3.2) into the tap funnel in the side arm of the distillation flask (seeFigure 2). Flush out the apparatus with either nitrogen or argon for10min at a flow rate of10L/h and then reduce the flow rate to between1L/h and2L/h.5.4.2 Place30mL of

43、 water and5mL of absorption solution(3.3) in a50mL volumetric flask; fit the absorption tube and immerse its jet in the solution.Place3mL of hydrochloric acid solution(3.10) in the acid trap. Add the acid mixture from the tap funnel to the distillation flask.5.4.3 Increase the flow of nitrogen/argon

44、 to between3 L/h and4L/h and gently boil the solution in the distillation flask for20min.Remove the absorption tube and volumetric flask. Remove the tube from the flask, washing the outside of the tube with water into the flask. Add to the flask5mL of4-amino-N, N-dimethylaniline reagent solution(3.4

45、),1mL of ammonium iron(III) sulphate solution(3.5), make up to the mark with water and mix. Allow to stand for10min out of direct sunlight.Measure the absorbance value at a wavelength of665nm using a20mm cell.5.4.4 After performing the blank determination(5.4.1 to5.4.3), cool the solution in the dis

46、tillation flask until the temperature of the solution is no more than50C.Place30mL of water and5mL of absorption solution(3.3) into a clean50mL volumetric flask; fit the absorption tube and immerse its jet into the solution.Transfer, by pipette,0.5mL (equivalent to54g of sulphur) of the sulphur stan

47、dard solution(3.9) into the distillation flask. Bring to the boil and boil gently for20min whilst maintaining the flow of nitrogen/argon at between3L/h and4L/h.NOTEIt is during boiling of the solution in the distillation flask that hydrogen sulphide is expelled.BS7317-5:1990 BSI 01-2000 5Continue wi

48、th the rest of the procedure described in5.4.3.5.4.5 Repeat the procedure described in5.4.4, for successive aliquots of sulphur standard solution(3.9) of1.0mL and1.5mL (equivalent to104g and154g of sulphur respectively), added by pipette to the distillation flask.5.5 Determinations5.5.1 Clean the di

49、stillation apparatus as described in5.1.2. Weigh and transfer0.5g of the test portion(5.3) to the distillation flask. Pour30mL of the acid mixture(3.2) into the tap funnel in the side arm of the distillation flask (Figure 2). Flush out the apparatus with nitrogen or argon for10min at a flow rate of10L/h and then reduce the flow rate to between1L/h and2L/h.5.5.2 Place30mL of water and5mL of the absorption solution(3.3) in a50mL volumetric flask; fit the absorption tube and immerse its jet in the solution.Place3mL of hydrochloric acid solution(