1、 g49g50g3g38g50g51g60g44g49g42g3g58g44g55g43g50g56g55g3g37g54g44g3g51g40g53g48g44g54g54g44g50g49g3g40g59g38g40g51g55g3g36g54g3g51g40g53g48g44g55g55g40g39g3g37g60g3g38g50g51g60g53g44g42g43g55g3g47g36g58alloys Spectrophotometric methodThe European Standard EN 12441-11:2006 has the status of a British
2、StandardICS 77.120.60Zinc and zinc alloys Chemical analysis Part 11: Determination of silicon in zinc BRITISH STANDARDBS EN 12441-11:2006BS EN 12441-11:2006This British Standard was published under the authority of the Standards Policy and Strategy Committee on 29 September 2006 BSI 2006ISBN 0 580 4
3、9171 4Amendments issued since publicationAmd. No. Date Commentscontract. Users are responsible for its correct application.Compliance with a British Standard cannot confer immunity from legal obligations.National forewordThis British Standard was published by BSI. It is the UK implementation of EN 1
4、2441-11:2006.The UK participation in its preparation was entrusted to Technical Committee NFE/8, Zinc.A list of organizations represented on NFE/8 can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a EUROPEAN STANDARDNORME EUROPEN
5、NEEUROPISCHE NORMEN 12441-11August 2006ICS 77.120.60English VersionZinc and zinc alloys - Chemical analysis - Part 11: Determinationof silicon in zinc alloys - Spectrophotometric methodZinc et alliages de zinc - Analyse chimique - Partie 11 :Dosage du silicium dans les alliages de zinc - Mthodespect
6、rophotomtriqueZink und Zinklegierungen - Chemische Analyse - Teil 11:Bestimmung von Silicium in Zinklegierungen -Spektrophotometrisches VerfahrenThis European Standard was approved by CEN on 7 July 2006.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the con
7、ditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Central Secretariat or to any CEN member.This European Standard exists in three o
8、fficial versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Central Secretariat has the same status as the officialversions.CEN members are the national standards bodies of Austria,
9、Belgium, Cyprus, Czech Republic, Denmark, Estonia, Finland, France,Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania,Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARD
10、IZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue de Stassart, 36 B-1050 Brussels 2006 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12441-11:2006: EEN 12441-11:2006 (E) 2 Contents Page Forew
11、ord3 1 Scope 4 2 Normative references 4 3 Terms and definitions .4 4 Principle4 5 Reagents.4 6 Apparatus .5 7 Sampling.5 8 Procedure .5 9 Calculation and expression of results.6 10 Test report 7 Annex A (informative) Additional information on international co-operative tests8 Annex B (informative) G
12、raphical representation of precision data9 Bibliography 10 EN 12441-11:2006 (E) 3 Foreword This document (EN 12441-11:2006) has been prepared by Technical Committee CEN/TC 209 “Zinc and zinc alloys”, the secretariat of which is held by AFNOR. This European Standard shall be given the status of a nat
13、ional standard, either by publication of an identical text or by endorsement, at the latest by February 2007, and conflicting national standards shall be withdrawn at the latest by February 2007. Within its programme of work, Technical Committee CEN/TC 209 entrusted CEN/TC 209/WG6 “Methods of analys
14、is and testing“ to prepare the following document: EN 12441-11, Zinc and zinc alloys Chemical analysis Part 11: Determination of silicon in zinc alloys Spectrophotometric method. This standard is a part of a series of eleven standards. The other standards are: Part 1: Determination of aluminium in z
15、inc alloys Titrimetric method 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: D
16、etermination 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
17、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 According to the CEN/CENELEC Internal Regulations, the national standards organizati
18、ons 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, Netherlands, Norway, Poland, Portugal, Romania, Slovakia
19、, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EN 12441-11:2006 (E) 4 1 Scope This European Standard specifies a spectrophotometric method for the determination of silicon in zinc alloys. It is applicable to the products specified in EN 1774 and EN 12844. It is suitable for the determina
20、tion of silicon contents (mass fractions) between 0,01 % and 0,1 %. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced doc
21、ument (including any amendments) applies. EN 1774, Zinc and zinc alloys Alloys for foundry purposes Ingot and liquid EN 12060:1997, Zinc and zinc alloys Method of sampling Specifications EN 12844, Zinc and zinc alloys Castings Specifications 3 Terms and definitions For the purposes of this European
22、Standard, the terms and definitions given in EN 12060:1997 apply. 4 Principle Direct spectrophotometric determination of silicomolybdenum blue after dissolution of the sample in hydrochloric and hydrofluoric acid. 5 Reagents 5.1 General During the test, use only reagents of known analytical grade. 5
23、.2 Bidistilled water (for preparation and dilution of all solutions) 5.3 Hydrochloric acid, = 1,19 g/ml 5.4 Hydrofluoric acid, = 1,13 g/ml 5.5 Boric acid 5.6 Ammonium molybdate (NH4)6Mo7O24 . 4H2O 5.7 Sodium metabisulfite Na2S2O55.8 Sodium sulfite Na2SO35.9 1-amino-2-naphtol-4-sulfonic acid EN 12441
24、-11:2006 (E) 5 5.10 Molybdate solution Dissolve 100 g of boric acid (5.6) in 3 litres of water and dissolve 25 g of ammonium molybdate (NH4)6Mo7O24. 4H2O in 250 ml of water. Transfer both solutions into a 5 litre volumetric flask. Dilute to the mark with water and mix. 5.11 Reducing solution Dissolv
25、e 100 g of Na2S2O5(5.7) in 600 ml of tepid water (fraction 1) and 4 g of Na2SO3(5.8) in 40 ml of tepid water (fraction 2). Introduce 2 g of 1-amino-2-naphtol-4-sulfonic acid (5.9) in 40 ml of tepid water (fraction 3) and mix. Add fraction 2 to fraction 3 and mix until the solution is clear. Dilute w
26、ith fraction 1. Transfer to a 1 l volumetric flask. Dilute to the mark with water and mix. 5.12 Silicon standard solution In hot water dissolve, 0,6 342 g of ammonium hexafluoro-silicate (NH4)2SiF6, dried beforehand between 105 C and 110 C and cooled in a dessiccator. Let cool, then transfer in a 50
27、0 ml volumetric polyethylene flask. Dilute to the mark with water and mix. 1 ml of this solution contains 200 g of silicon. 6 Apparatus 6.1 Plastic bottles with screw cap, volumetric flasks, pipettes etc., made of polytetrafluoroethylene (PTFE), polypropylene (PP), polyethylene (PE), polymethylpente
28、ne or other equivalent polymers. New vessels have to be cleaned with warm hydrofluoric acid (5.4). 6.2 In addition to standard laboratory apparatus, the following shall be used: magnetic stirrer and stirring bars (magnetic core with PTFE jacket); spectrophotometer, set at a wavelength of 820 nm and
29、using 1 cm optical cells. NOTE The dilution and aliquot parts defined in this standard only apply if 1 cm cells are used. It is necessary to apply the appropriate modifications in the case of cells with other dimensions. 7 Sampling The test sample shall be selected and prepared in accordance with th
30、e procedure given in EN 12060. 8 Procedure 8.1 Test portion Weigh 1 g of the test sample to the nearest 0,001 g. 8.2 Blank test Simultaneously with each determination, carry out a blank test using the same quantities of each reagent and following the same procedure. EN 12441-11:2006 (E) 6 8.3 Prepar
31、ation of the test solution 8.3.1 Introduce the test portion (8.1) in a 50 ml plastic bottle, add 5 ml of water and then 12 ml of hydrochloric acid (5.3) in portions of 1 ml or 2 ml. Cool if the reaction is too violent. 8.3.2 After effervescence has stopped, add 2 ml of hydrofluoric acid (5.4). 8.3.3
32、 After effervescence has stopped, add a magnetic stirrer, close the bottle with a screw cap and stir until complete dissolution. Depending of the alloy this may take between 0,5 h and 3 h. 8.3.4 Transfer the solution quantitatively into a 50 ml plastic volumetric flask. Dilute to the mark with water
33、 and mix. 8.3.5 Transfer 1 ml of solution 8.3.4 into a 50 ml plastic volumetric flask, let stand for 1 h, then add 45 ml of molybdate solution (5.10). 8.3.6 After 15 minutes, add 2 ml of reducing solution (5.11). Dilute to the mark with water and mix. 8.3.7 After 15 minutes, measure the absorbance o
34、f this solution against the blank test solution (8.2) in 1 cm cells using the spectrophotometer (6.2) set at a wavelength of 820 nm, after first measuring the calibration solutions as in (8.4). 8.4 Calibration NOTE The following is valid for 1 cm cells and for 0 mg, 0,1 mg, 0,2 mg, 0,4 mg, 0,6 mg, 0
35、,8 mg, 1,0 mg and 1,2 mg of silicon corresponding to contents (mass fractions) in the test portion of 0 %, 0,01 %, 0,02 %, 0,04 %, 0,06 %, 0,08 %, 0,10 % and 0,12 %. It is necessary to apply the appropriate modifications in the case of cells of different lengths. 8.4.1 Introduce into a series of 50
36、ml plastic flasks, 0,00 ml, 0,50 ml, 1,00 ml, 2,00 ml, 3,00 ml, 4,00 ml, 5,00 ml and 6,00 ml respectively of the silicon standard solution (5.12). 8.4.2 Add 5 ml of water, 12 ml of hydrochloric acid (5.3) and 2 ml of hydrofluoric acid (5.4). Dilute to the mark with water and mix. 8.4.3 Transfer 1 ml
37、 of solution (8.4.2) into 50 ml plastic flasks and add 45 ml of Molybdate solution (5.10). 8.4.4 Wait for 15 minutes, then add 2 ml of reducing solution (5.11). Dilute to the mark with water and homogenise. 8.4.5 Wait for 15 minutes, then measure the absorbance of each solution against the zero stan
38、dard of the calibration range, in 1 cm cells, using the spectrophotometer (6.2), at a wavelength of 820 nm. 8.4.6 Establish a calibration graph by plotting the measured absorbances of the calibration solutions against their respective contents (mass fractions). 9 Calculation and expression of result
39、s 9.1 Method of calculation Determine from the measured absorbances of the test solution the associated amount of silicon from the calibration curve (8.4). If a number of determinations (n) are carried out then a mean of all results shall be determined. The results shall be expressed as specified in
40、 EN 1774 and EN 12844. EN 12441-11:2006 (E) 7 9.2 Precision A planned trial of this method was carried out by 10 laboratories using 6 samples with 6 levels of silicon contents, each laboratory making three determinations of silicon content in each sample (see Notes 1 and 2). NOTE 1 Two of the three
41、determinations were carried out under repeatability conditions as defined in ISO 5725 i.e., one operator, same apparatus, identical operating conditions, same calibrations and a minimum period of time. NOTE 2 The third determination was carried out at a different time (on a different day), by the sa
42、me operator as in note 1, using the same apparatus and different calibrations. The details of the samples used and the mean results obtained are given in the Tables A.1 and A.2. The results obtained were treated statistically in accordance with ISO 5725-1. The data obtained showed a logarithmic rela
43、tionship between the silicon content and the repeatability limit r and reproducibility limits Rwand R of the results (see note 3), as summarised in Table 1. The graphical representation of the data is shown in figure B.1. NOTE 3 From the two values obtained in day 1, the repeatability limit r and th
44、e reproducibility limit R were calculated using the procedure specified in ISO 5725. From the first value obtained in day 1 and the value obtained in day 2, the within-laboratory reproducibility limit Rw was calculated using the procedure specified in ISO 5725. Table 1 Results for repeatability limi
45、t and reproducibility limits Silicon content Repeatability limit Reproducibility limits % (mass fraction) r Rw R 0,01 0,0 013 0,0 013 0,0 020 0,02 0,0 017 0,0 019 0,0 031 0,05 0,0 024 0,0 034 0,0 054 0,1 0,0 030 0,0 051 0,0 082 0,2 0,0 038 0,0 078 0,0 126 10 Test report The test report shall include
46、 the following details: a) identification of sample; b) test method used (i.e. reference to this standard); c) silicon content, expressed as percentage by mass, giving where possible the results for the individual and the mean value; d) any unusual occurrence during the determination; e) any steps i
47、n the procedure beyond those specified in this standard, and any circumstances that may have affected the results; f) date of the test report; g) name of the laboratory or testing organisation; h) signature of the laboratory manager or other responsible person. EN 12441-11:2006 (E) 8 Annex A (inform
48、ative) Additional information on international co-operative tests Table 1 was derived from the results of European analytical trials carried out from 2001 to 2003 on 6 test samples in 6 countries involving 10 laboratories. The results of the trials were reported in the document CEN/TC 209/WG 6 N 149
49、 and are shown in Table A.1. The test samples used are listed in the Table A.2. Table A.1 Detailed results obtained in the inter-laboratory test Precision data Silicon content (mass fraction) (%) Repeatability Reproducibility SAMPLE Referee Found r Rw R ZL2-S 0,0 220 0,0 205 0,0 015 0,0 017 0,0 022 ZL3-S 0,0 100 0,0 083 0,0 019 0,0 019 0,0 032 ZL5-S 0,0 130 0,0 126 0,0 018 0,0 017 0,0 034 ZL8-S 0,0 510 0,0 494 0,0 018 0,0 035 0,0 040 ZL12-S 0,0 800 0,0 778
