BS 6783-8-1986 Sampling and analysis of nickel ferronickel and nickel alloys - Method for determination of sulphur in nickel ferronickel and nickel alloys by iodimetric titration a.pdf

1、BRITISH STANDARD BS 6783-8: 1986 EN 27527:1991 ISO 7527:1985 Incorporating Amendment No.1 Sampling and analysis of nickel, ferronickel and nickel alloys Part 8: Method for determination of sulphur in nickel, ferronickel and nickel alloys by iodimetric titration after induction furnace combustion ISO

2、 title: Nickel, ferronickel and nickel alloysDetermination of sulfur contentIodimetric titration method after induction furnace combustion The European Standard EN27527:1991 has the status of a British Standard UDC 669.24:669.1524-198:620.1:543.242.3:543.845BS6783-8:1986 This British Standard, havin

3、g been prepared under the directionof the Non-ferrous Metals Standards Committee, waspublished under the authorityof the Board of BSI andcomes into effect on 31 December1986 BSI 11-1999 The following BSI references relate to the work on this standard: Committee reference NFM/10 Draft for comment84/3

4、9890 DC ISBN 0 580 15527 7 Committees responsible for this British Standard The preparation of this British Standard was entrusted by the Non-ferrous Metals Standards Committee (NFM/-) to Technical Committee NFM/10, upon which the following bodies were represented: British Non-ferrous Metals Federat

5、ion British Steel Industry Engineering Equipment and Materials Users Association Ministry of Defence Process Plant Association Stainless Steel Fabricators Association of Great Britain Coopted members Amendments issued since publication Amd. No. Date of issue Comments 6994 February 1992 Indicated by

6、a sideline in the marginBS6783-8:1986 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii 1 Scope and field of application 3 2 References 3 3 Principle 3 4 Reagents and materials 3 5 Apparatus 3 6 Sampling and samples 4 7 Procedure 4 8 Expression of results 5 9

7、 Notes on procedure and equipment 5 10 Test report 6 Annex Examples of compositions of nickel, ferronickel and nickel alloys 7 Table 1 Calibration example 5 Table 2 Results of statistical analysis 6 Table 3 Examples of composition of nickel (%) 7 Table 4 Examples of composition of ferronickel (%) 7

8、Table 5 Examples of composition of nickel alloys (%) 7 Publications referred to Inside back coverBS6783-8:1986 ii BSI 11-1999 National foreword This Part of BS6783 has been prepared under the direction of the Non-ferrous Metals Standards Committee. It is identical with ISO7527:1985 “Nickel, ferronic

9、kel, and nickel alloysDetermination of sulfur contentIodimetric titration method after induction furnace combustion” published by the International Organization for Standardization (ISO). In1991 the European Committee for Standardization (CEN) accepted ISO7527:1985 as European Standard EN27527:1991

10、without any modifications. At present this British Standard consists of nine Parts all concerned with analysis of nickel, ferronickel and nickel alloys. Further International Standards are in preparation on sampling and analysis of nickel, ferronickel and nickel alloys and, when available, these wil

11、l be published as further Parts of this BritishStandard. Terminology and conventions. The text of the International Standard has been approved as suitable for publication as a British Standard without deviation. Some terminology and certain conventions are not identical with those used in British St

12、andards; attention is drawn especially to the following. The comma has been used as a decimal marker. In British Standards it is current practice to use a full point on the baseline as the decimal marker. Wherever the words “International Standard” appear, referring to this standard, they should be

13、read as “Part of BS6783”. In British Standards it is current practice to use the symbol “L” for litre (andinits submultiples) rather than “l” and to use the spelling “sulphur”, etc., instead of sulfur, etc. The Technical Committee has reviewed the provisions of ISO385-1 and ISO648, to which referenc

14、e is made in the text, and has decided that they are acceptable for use in conjunction with this standard. ISO385-1 is related to BS846:1985 “Specification for burettes” and ISO648 is related to BS1583:1986 “Specification for one-mark pipettes”. A British Standard does not purport to include all the

15、 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. Cross-references International Standards Corresponding British Standards ISO1042:1983 BS1792:19

16、82 Specification for one-mark volumetric flasks (Identical) ISO5725:1981 BS5497 Precision of test methods Part1:1979 Guide for the determination of repeatability and reproducibility for a standard test method (Technically equivalent) ISO7525:1985 BS6783 Sampling and analysis of nickel, ferronickel a

17、nd nickel alloys Part6:1986 Method for determination of sulphur in nickel by methylene blue molecular absorption spectrometry after generation of hydrogen sulphide (Identical) Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theENtitle page, pages2 to8, an

18、 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.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 27527 November 1991 UDC 669.24:669.1524-198:

19、620.1:543.242.3:543.845 Descriptors: Nickel, nickel alloys, ferronickel, chemical analysis, determination of content, sulphur, volumetric method, iodimetry, combustion analysis, induction furnaces English version Nickel, ferronickel and nickel alloysDetermination of sulfur contentIodimetric titratio

20、n method after induction furnace combustion (ISO7527:1985) Nickel, ferro-nickel et alliages de nickel Dosage du soufreMthode par titration iodomtrique aprs combustion dans un four induction (ISO7527:1985) Nickel, Ferronickel und Nickellegierung Bestimmung des Schwefelgehaltes Iodometrisches Titratio

21、nverfahren nach Verbrennung im Induktionsofen (ISO7527:1985) This European Standard was approved by CEN on1991-11-06. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without a

22、ny alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made b

23、y translation under the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Lu

24、xembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels CEN1991 Copyright reserved to all CEN members Ref.

25、 No. EN 27527:1991 E2 blankEN27527:1991 BSI 11-1999 3 1 Scope and field of application This International Standard specifies a titrimetric method after combustion for the determination of the sulfur content of nickel and ferronickel in the range0,001to0,3% (m/m), and of nickel alloys in the range0,0

26、02 to0,1% (m/m). Examples of compositions are given in the Annex. 2 References ISO385-1, Laboratory glasswareBurettes Part1: General requirements. ISO648, Laboratory glasswareOne-mark pipettes. ISO1042, Laboratory glasswareOne-mark volumetric flasks. ISO5725, Precision of test methods Determination

27、of repeatability and reproducibility by inter-laboratory tests. ISO7525, NickelDetermination of sulfur contentMethylene blue molecular absorption spectrometric method after generation of hydrogen sulfide. 3 Principle Combustion of a test portion in a flow of oxygen at a high temperature in a high fr

28、equency induction furnace in the presence of fluxes and accelerators. Absorption of the sulfur dioxide formed in an acidified starch-iodide solution and continuous titration with potassium iodate standard volumetric solution. 4 Reagents and materials During the analysis, unless otherwise stated, use

29、 only reagents of recognized analytical grade and only distilled water or water of equivalent purity. 4.1 Oxygen (O 2 ),99,5% (m/m) minimum. 4.2 Ascarite or soda lime,0,7 to1,2 mm(14 to22 mesh). 4.3 Magnesium perchlorate Mg(ClO 4 ) 2 ,0,7 to1,2mm (14 to22 mesh). 4.4 Glass-wool 4.5 Crucibles and lids

30、 4.5.1 Ceramic crucibles shall be of precise dimensions so that the sample is positioned correctly in the induction coil of the furnace (see9.1). 4.5.2 Pre-ignite the crucibles in air or oxygen in a furnace for not less than1h at1100 C and store in a desiccator or closed container. A resistance furn

31、ace with a combustion tube through which a flow of oxygen passes may be used. Crucible lids, used to help retain the solid oxidation products in the hot zone, are pre-ignited in a similar manner. 4.6 Fluxes: Low sulfur tin, copper plus tin, copper or vanadium pentoxide (see9.2). 4.7 Accelerators: Lo

32、w sulfur copper, iron, tungsten or nickel (see9.2). 4.8 Nickel, low sulfur of known value 0,001% (m/m). 4.9 Standard reference steel, containing0,1 to0,2%(m/m) sulfur. 4.10 Hydrochloric acid, 20 =1,19g/ml, diluted1+99. 4.11 Starch-iodide, solution. Transfer9g of soluble starch to a50ml beaker, add5

33、to10ml of water and stir until a smooth paste is obtained. Pour the mixture slowly into500ml of boiling water. Cool, add15g of potassium iodide and stir until it is dissolved. Dilute to1litre with water and mix. 4.12 Potassium iodate, standard volumetric solution. Dissolve exactly0,2225g of potassiu

34、m iodate in900ml of water containing1g of sodium hydroxide. Transfer to a1000ml one-mark volumetric flask. Make up to the mark with water and mix. 1ml of this standard volumetric solution is equivalent to0,1mg S. 4.13 Potassium iodate, standard volumetric solution. Transfer200ml of potassium iodate

35、solution(4.12) to a1000ml one-mark volumetric flask. Make up to the mark with water and mix. 1ml of this standard volumetric solution is equivalent to0,02mg S. NOTEThe sulfur equivalents of4.12 and4.13 are based on the complete conversion and recovery of sulfur as sulfur dioxide. Well-established st

36、andards of known sulfur content are used for solution standardization. 5 Apparatus 5.1 The apparatus required for combustion in a high frequency induction furnace and titration of the evolved sulfur dioxide may be obtained commercially from a number of manufacturers. Follow the manufacturers instruc

37、tions for the operation of the equipment (see9.3).EN27527:1991 4 BSI 11-1999 5.2 Burettes, of capacity50ml, graduated in divisions of0,1ml; and of capacity10ml, graduatedin divisions of0,02ml, in accordance with ISO385-1, class A. 5.3 Pipettes, in accordance with ISO648, class A. 5.4 Volumetric flas

38、ks, in accordance with ISO1042, class A. 6 Sampling and samples 6.1 Sampling and preparation of the laboratory sample shall be carried out by normal agreed procedures or, in case of dispute, by the relevant International Standard. 6.2 The laboratory sample normally is in the form of a powder, granul

39、es, millings or drillings and no further preparation of the sample is necessary. 6.3 If it is suspected that the laboratory sample is contaminated with oil or grease from the milling or drilling process, it shall be cleaned by washing with high purity acetone and drying in air. 6.4 If the laboratory

40、 sample contains particles or pieces of widely varying sizes, the test portion should be obtained by riffling. 7 Procedure WARNING The risks related to combustion analysis are mainly burns in pre-igniting the ceramic crucibles and in the fusions. Use crucible tongs at all times and suitable containe

41、rs for the used crucibles. Normal precautions for handling oxygen cylinders shall be taken. 7.1 Determination 7.1.1 Weigh, to the nearest0,001g,0,9 to1,1g of the test sample, and transfer to a pre-ignited crucible(4.5) containing a suitable amount of the preferred flux(4.6). Add the appropriate quan

42、tity of accelerator(4.7), if required. The flux and accelerator used will depend on the individual characteristics of the equipment and the type of material being analysed. Typical additions to a1,0g test portion are2g of copper,1g of copper plus1g of iron,2 to3g of tungsten, or1g of vanadium pentox

43、ide plus1g of iron powder. Place the crucible lid in position. 7.1.2 Place the crucible and contents on the pedestal post of the furnace and, with oxygen flowing, raise to the combustion position. 7.1.3 Add50 to70ml of hydrochloric acid(4.10) and2ml of starch-iodide solution(4.11) to the absorption

44、vessel. Add sufficient potassium iodate solution(4.13) from a burette to obtain the intensityof the blue colour which will be taken as the end-point of the final titration. Refill the burette to the zero mark. NOTEFor sulfur contents higher than0,02% (m/m) use the stronger iodate solution(4.12). 7.1

45、.4 Switch on the furnace and combust the sample while passing oxygen through the system. Titrate continuously with the potassium iodate solution(4.13) to maintain the blue starch-iodine colour chosen as the end-point. Do not allow the solution to become colourless at any time during the titration be

46、cause of possible loss of sulfur dioxide. After the contents of the crucible have combusted completely, as shown by no further decrease of the blue colour, usually after about5min, turn off the power supply to the induction coil. 7.1.5 Note the volume of titrant added. 7.1.6 Repeat7.1.1 to7.1.5. 7.2

47、 Blank test 7.2.1 Charge a pre-ignited crucible(4.5) with the quantity of flux and accelerator to be used in the determination(7.1) and add1,00g of pure nickel of known low sulfur content(4.8). 7.2.2 Proceed as directed in7.1.2 to7.1.5. NOTE 1The volume of titrant corresponds to the blank due to the

48、 crucible, flux, accelerator and sulfur in the pure nickel. NOTE 2The blank should not exceed0,001% (m/m) sulfur. NOTE 3If the blank reading is abnormally high, investigate and eliminate the source of contamination. 7.3 Calibration 7.3.1 Select a certified standard reference steel(4.9). NOTEFor ferr

49、onickel, reference materials with a higher sulfur content are used. 7.3.2 Use the certified standard reference steel in conjunction with pure nickel of low sulfur content 0,001% (m/m) which is known or has been determined by ISO7525. 7.3.3 Weigh appropriate proportions of the two materials (7.3.1 and7.3.2) into a pre-ignited crucible, to cover the high end of the calibration range. Add the preselected amounts of flux and accelerator and combust as directed in7.1.2 to7.1.5. 7.3.4 Repeat7.3.3 to check the repeatability of the