BS EN 12441-1-2002 Zinc and zinc alloys - Chemical analysis - Determination of aluminium in zinc alloys - Titrimetric method《锌及锌合金 化学分析 锌合金中铝的测定 滴定法》.pdf

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1、BRITISH STANDARD BS EN 12441-1:2002 Incorporating Amendment No. 1 Zinc and zinc alloys Chemical analysis Part 1: Determination of aluminium in zinc alloys Titrimetric method The European Standard EN 12441-1:2001, with the incorporation of amendment A1:2004, has the status of a British Standard ICS 7

2、7.120.60; 77.040.30 BS EN 12441-1:2002 This British Standard, having been prepared under the direction of the Engineering Sector Policy and Strategy Committee, was published under the authority of the Standards Policy and Strategy Committee on 23 January 2002 BSI 26 August 2004 ISBN 0 580 38161 7 Na

3、tional foreword This British Standard is the official English language version of EN 12441-1:2001, including amendment A1:2004. It supersedes BS 3630-6:1965 which is withdrawn. The UK participation in its preparation was entrusted by Technical Committee NFE/8, Zinc and zinc alloys, to Subcommittee N

4、FE/8/4, Sampling and analysis of zinc and zinc alloys, which has the responsibility to: A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in t

5、his document may be found in the BSI Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Search” facility of the BSI Electronic Catalogue or of British Standards Online. This publication does not purport to include all the necessary provisions of a c

6、ontract. Users are responsible for its correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposal

7、s for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pages 2 to 10, an inside back cover and a back cover. The BSI cop

8、yright notice displayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date Comments 15354 26 August 2004 Changes to Table 1 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12441-1 October 2001 + A1 August 2004 ICS 77.040.30; 77.120.60

9、 English version Zinc and zinc alloys - Chemical analysis - Part 1: Determination of aluminium in zinc alloys - Titrimetric method (includes amendment A1:2004) Zinc et alliages de zinc - Analyse chimique - Partie 1: Dosage de laluminium dans les alliages de zinc - Mthode titrimtrique (inclut lamende

10、ment A1:2004) Zink und Zinklegierungen - Chemische Analyse - Teil 1: Bestimmung von Aluminium in Zinklegierungen - Titrimetrisches Verfahren (enthlt nderung A1:2004) This European Standard was approved by CEN on 11 August 2001, and amendment A1 was approved by CEN on 21 June 2004. CEN members are bo

11、und to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the

12、Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as

13、the official versions. CEN members are the national standards bodies of Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spa

14、in, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels 2001 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national

15、 Members. Ref. No. EN 12441-1:2001 + A1:2004 EEN 12441-1:2001 (E) 2 Contents page Foreword3 1 Scope5 2 Normative references5 3 Terms and definitions .5 4 Principle5 5 Reagents.5 6 Apparatus.6 7 Sampling.6 8 Procedure.6 9 Calculation and expression of results.7 10 Test report8 Annex A (informative) A

16、dditional information on round - Robin tests 9 Annex B (informative) Graphical representation of precision data .10 EN 12441-1:2001 (E) 3 Foreword This European Standard has been prepared by Technical Committee CEN/TC 209, “Zinc and zinc alloys“, the secretariat of which is held by AFNOR. This Europ

17、ean Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by April 2002, and conflicting national standards shall be withdrawn at the latest by April 2002. Within its programme of work, Technical Committee CEN/TC 209 en

18、trusted CEN/TC 209/WG 6 “Methods of analysis and testing” with the preparation of the following document: EN 12441-1, Zinc and zinc alloys - Chemical analysis - Part 1: Determination of aluminium in zinc alloys Titrimetric method. This standard is part of a series of eleven standards. The other stan

19、dards are: Part 2 : Determination of magnesium in zinc alloys Flame atomic absorption spectrometric method Part 3 : Determination of lead, cadmium and copper - Flame atomic absorption spectrometric method Part 4 : Determination of iron in zinc alloys - Spectrophotometric method Part 5 : Determinatio

20、n of iron in primary zinc - Spectrophotometric method Part 6 : Determination of aluminium and iron - Flame atomic absorption spectrometric method Part 7 : Determination of tin - Flame atomic absorption spectrometric method after extraction Part 8 : Determination of tin in secondary zinc - Flame atom

21、ic absorption spectrometric method Part 9 : Determination of nickel in zinc alloys - Flame atomic absorption spectrometric method Part 10 : Determination of chromium and titanium in zinc alloys Spectrophotometric method Part 11 : Determination of silicon in zinc alloys - Spectrophotometric method Th

22、e annexes A and B are informative. According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, L

23、uxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom. EN 12441-1:2001 (E) 4 Foreword to amendment A1 This document (EN 12441-1:2001/A1:2004) has been prepared by Technical Committee CEN/TC 209, “Zinc and zinc alloys“, the secretariat of which is held by AFNOR.

24、This Amendment to theEuropean Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by February 2005, and conflicting national standards shall be withdrawn at the latest by Februaryl 2005. According to the CEN/CENELEC I

25、nternal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Ne

26、therlands, Norway, Poland, Portugal, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 12441-1:2001 (E) 5 1 Scope This European Standard specifies a titrimetric method for the determination of aluminium in zinc alloys. It is applicable to the products specified in EN 1774 and EN

27、12844. It is suitable for the determination of aluminium contents (mass fractions) between 3 % and 30 %. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropriate places in the

28、 text, and the publications are listed hereafter. For dated references, subsequent amendments to or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references, the latest edition of the publication referred to

29、applies (including amendments).5 EN 1774, Zinc and zinc alloys - Alloys for foundry purposes - Ingot and liquid. EN 12060, Zinc and zinc alloys - Method of sampling - Specifications. EN 12844, Zinc and zinc alloys - Castings - Specifications. ISO 5725-1, Accuracy (trueness and precision) of measurem

30、ent methods and results - Part 1: General principles and definitions. 3 Terms and definitions For the purposes of this European Standard, the terms and definitions given in EN 12060 apply. 4 Principle An excess of EDTA is added to the hydrochloric solution of a test portion. This is followed by quan

31、titative complexing of the excess with a standard zinc solution. The aluminium-EDTA complex is decomposed with sodium fluoride and the liberated EDTA is titrated against a standard zinc solution. 5 Reagents 5.1 General During the test, use only reagents of known analytical grade and distilled or dem

32、ineralized water. 5.2 Hydrochloric acid, = 1,19 g/ml 5.3 Nitric acid, = 1,4 g/ml 5.4 Hydrochloric acid (1 + 1) Mix 1 volume of hydrochloric acid (5.2) with 1 volume of water. 5.5 Hydrogen peroxide, 30 % (mass fraction) 5.6 Hydroxylammonium chloride, 200 g/l solution 5.7 Ethylenediamine tetra-acetic

33、acid disodium salt (EDTA), 65 g/l solution EN 12441-1:2001 (E) 6 5.8 Ammonia solution, = 0,91 g/ml 5.9 Sodium fluoride, saturated solution Dissolve 60 g of sodium fluoride in 1 l of boiling water. Cool to room temperature and filter. 5.10 Sodium acetate, buffer solution Dissolve 135 g of sodium acet

34、ate (CH 3 COONa, 3H 2 O) in approximately 300 ml of water. Add 13 ml of glacial acetic acid (5.16). Check that the pH is within the range 5 to 5,5. Make up the volume to 500 ml with water. 5.11 Standard zinc solution, 0,05 M Dissolve 3,269 g of high purity zinc in 40 ml of hydrochloric acid (1 + 1)

35、(5.4) in a 250 ml beaker fitted with a watch-glass. Dilute with 100 ml of water. Add 2 drops of methyl red solution (5.12). Neutralize with ammonia solution (5.8). Add hydrochloric acid (1+1) (5.4) drop by drop until the colour changes to red. Transfer quantitatively to a 1 l volumetric flask. Add 5

36、 ml of hydrochloric acid (1 + 1) (5.4), dilute to the mark with water and mix. 1 ml of this solution corresponds to 1,349 mg of aluminium. 5.12 Methyl red, ethanolic solution Dissolve 0,02 g of methyl red in 100 ml of ethanol. 5.13 Xylenol orange, 10 g/l solution 5.14 Aqua regia Mix 3 volumes of hyd

37、rochloric acid (5.2) with 1 volume of nitric acid (5.3). 5.15 Xylene cyanol, 1 g/l solution. NOTE Use of this reagent is optional. 5.16 Glacial acetic acid, = 1,05 g/ml 6 Apparatus All glassware used for the preparation of the solutions and for the implementation of the method shall be cleaned with

38、boiling aqua regia (5.14) prior to use. 7 Sampling The test sample shall be selected and prepared in accordance with the procedure given in EN 12060. 8 Procedure 8.1 Test portion Weigh, 5 g of the test sample to the nearest 0,001 g. 8.2 Determination 8.2.1 Introduce the test portion (8.1) into a 500

39、 ml beaker fitted with a watch-glass and dissolve by carefully adding 50 ml of hydrochloric acid (1 + 1) (5.4). Oxidize and complete the dissolution by adding a few drops of hydrogen peroxide (5.5). EN 12441-1:2001 (E) 7 8.2.2 Add 5 ml of hydroxylammonium chloride solution (5.6) to decompose the exc

40、ess of hydrogen peroxide. Heat the beaker carefully. Dilute to 100 ml with water and cool to room temperature. Transfer quantitatively: a) for Al contents (mass fractions) 15 % : to a 250 ml volumetric flask ; b) for Al contents (mass fractions) 15 % : to a 1 000 ml volumetric flask. Dilute to the m

41、ark with water and mix. 8.2.3 Transfer a 25 ml aliquot to a 500 ml conical flask. 8.2.4 Add successively : a) approximately 100 ml of water; b) 1) for Al contents (mass fractions) 15 % : 55 ml of EDTA solution (5.7) ; 2) for Al contents (mass fractions) 15 % : 25 ml of EDTA solution (5.7). c) 5 drop

42、s of methyl red solution (5.12). 8.2.5 Neutralize exactly with ammonia solution (5.8) until the colour changes to yellow. Add 25 ml of buffer solution (5.10). 8.2.6 Boil for 2 to 3 min. Cool to room temperature. 8.2.7 Add 2 to 3 drops of xylenol orange solution (5.13). NOTE For some operators the en

43、d-point can be made even more readily detectable by the addition of not more than 1 ml of xylene cyanol solution (5.15). 8.2.8 Titrate the excess of EDTA with standard zinc solution (5.11) until the colour changes to purple. 8.2.9 Add 25 ml of sodium fluoride solution (5.9). Boil for 2 to 3 minutes.

44、 Cool to room temperature. 8.3 Volumetric measurement Titrate the liberated EDTA with the standard zinc solution (5.11) until the colour changes to purple. 9 Calculation and expression of results 9.1 Method of calculation The aluminium content shall be given, as a percentage by mass, a) for Al conte

45、nts (mass fractions) 15 % : by the formula V x 0,269 8 ; b) for Al contents (mass fractions) 15 % : by the formula V x 1,079 2, where V is the volume, in millilitres, of standard zinc solution used to titrate the liberated EDTA (see 8.3). If a number of determinations are carried out, then the mean

46、of all the results shall be calculated by adding the individual results and dividing by the number of individual results. The results shall be expressed as specified in EN 1774 and EN 12844. EN 12441-1:2001 (E) 8 9.2 Precision Repeatability and reproductibility limits are given in Table 1. NOTE Tabl

47、e 1 has been established according to annex A. Graphical representation of precision data is given in annex B. Table 1 Repeatability and reproducibility limits Aluminium content Repeatability limit Reproducibility limit % r R wR 2 0,028 0,025 0,050 5 0,050 0,050 0,102 10 0,078 0,085 0,175 20 0,120 0

48、,143 0,300 30 0,155 0,195 0,410 10 Test report The test report shall include the following: a) identification of the sample ; b) test method used, (i.e. reference to this standard) ; c) aluminium content, expressed as percentage by mass, giving where possible the results for the individual and mean

49、values ; d) any unusual occurrence during the determination ; e) any steps in the procedure beyond those specified in this standard, and any circumstances that may have affected the results ; f) date of testing ; g) name of laboratory or testing organization ; h) signature of the laboratory manager or other responsible person. EN 12441-1:2001 (E) 9 Annex A (informative) Additional information on round - Robin tests Table 1