1、BRITISH STANDARD BS EN 12441-10:2004 Zinc and zinc alloys Chemical analysis Part 10: Determination of chromium and titanium in zinc alloys Spectrophotometric method The European Standard EN 12441-10:2004 has the status of a British Standard ICS 77.040.30; 77.120.60 BS EN 12441-10:2004 This British S
2、tandard was published under the authority of the Standards Policy and Strategy Committee on 20 January 2005 BSI 20 January 2005 ISBN 0 580 45287 5 National foreword This British Standard is the official English language version of EN 12441-10:2004. The UK participation in its preparation was entrust
3、ed to Technical Committee NFE/8, Zinc, which has the responsibility to: A list of organizations represented on this committee can be obtained on request to its secretary. Cross-references The British Standards which implement international or European publications referred to in this document may be
4、 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 contract. Users are
5、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 proposals for change, and k
6、eep 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 12, an inside back cover and a back cover. The BSI copyright notice displ
7、ayed in this document indicates when the document was last issued. Amendments issued since publication Amd. No. Date CommentsEUROPEANSTANDARD NORMEEUROPENNE EUROPISCHENORM EN1244110 December2004 ICS77.040.30;77.120.60 Englishversion ZincandzincalloysChemicalanalysisPart10:Determination ofchromiumand
8、titaniuminzincalloysSpectrophotometric method ZincetalliagesdezincAnalysechimiquePartie10: Dosageduchromeetdutitanedanslesalliagesdezinc Mthodespectrophotomtrique ZinkundZinklegierungenChemischeAnalyseTeil10: BestimmungvonChromundTitaninZinklegierungen SpektrophotometrischesVerfahren ThisEuropeanSta
9、ndardwasapprovedbyCENon4November2004. CENmembersareboundtocomplywiththeCEN/CENELECInternalRegulationswhichstipulatetheconditionsforgivingthisEurope an Standardthestatusofanationalstandardwithoutanyalteration.Uptodatelistsandbibliographicalreferencesconcernings uchnational standardsmaybeobtainedonapp
10、licationtotheCentralSecretariatortoanyCENmember. ThisEuropeanStandardexistsinthreeofficialversions(English,French,German).Aversioninanyotherlanguagemadebytra nslation undertheresponsibilityofaCENmemberintoitsownlanguageandnotifiedtotheCentralSecretariathasthesamestatusast heofficial versions. CENmem
11、bersarethenationalstandardsbodiesofAustria,Belgium,Cyprus,CzechRepublic,Denmark,Estonia,Finland,France, Germany,Greece,Hungary,Iceland,Ireland,Italy,Latvia,Lithuania,Luxembourg,Malta,Netherlands,Norway,Poland,Portugal, Slovakia, Slovenia,Spain,Sweden,SwitzerlandandUnitedKingdom. EUROPEANCOMMITTEEFOR
12、STANDARDIZATION COMITEUROPENDENORMALISATION EUROPISCHESKOMITEEFRNORMUNG ManagementCentre:ruedeStassart,36B1050Brussels 2004CEN Allrightsofexploitationinanyformandbyanymeansreserved worldwideforCENnationalMembers. Ref.No.EN1244110:2004:EEN 12441-10:2004 (E) 2 Contents Page Foreword3 1 Scope4 2 Normat
13、ive references4 3 Terms and definitions .4 4 Principle4 5 Reagents.4 6 Apparatus.6 7 Sampling.6 8 Procedure.6 9 Calculation and expression of results.8 10 Test report8 Annex A (informative) Additional information on international co-operative tests .9 Annex B (Informative) Graphical representation o
14、f precision data .10 Bibliography 12 EN 12441-10:2004 (E) 3 Foreword This document (EN 12441-10:2004) 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 national standard, either
15、 by publication of an identical text or by endorsement, at the latest by June 2005, and conflicting national standards shall be withdrawn at the latest by June 2005. Within its programme of work, Technical Committee CEN/TC 209 entrusted CEN/TC 209/WG6 “Methods of analysis and testing“ to prepare the
16、 following document: EN 12441-10, Zinc and zinc alloys Chemical analysis Part 10: Determination of chromium and titanium in zinc alloys Spectrophotometric method This document is a part of a series of eleven standards. The other documents are: Part 1: Determination of aluminium in zinc alloys Titrim
17、etric 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: Determination of i
18、ron 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 atomic absorption spe
19、ctrometric method Part 9: Determination of nickel in zinc alloys Flame atomic absorption spectrometric method Part 11: Determination of silicon in zinc alloys Spectrophotometric method According to the CEN/CENELEC Internal Regulations, the national standards organizations of the following countries
20、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, Slovakia, Slovenia, Spain, Sweden, Switzerland a
21、nd United Kingdom. EN 12441-10:2004 (E) 4 1 Scope This document specifies a spectrophotometric method for the determination of chromium and titanium in zinc alloys. It is applicable to the products specified in EN 988, EN 1774 and EN 12844. It is suitable for the determination of chromium and titani
22、um contents (mass fractions) between 0,05 % and 0,50 %. 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 document (inclu
23、ding 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 document, the terms a
24、nd definitions given in EN 12060:1997 apply. 4 Principle For both determinations the same dissolution and oxidation step is used. Chromium is determined by spectrophotometry of the violet chromium diphenylcarbazide complex. Titanium is determined by spectrophotometry of the red chromotropic acid tit
25、anium complex, formed in a solution buffered at pH 2,9. 5 Reagents 5.1 General During the test, use only reagents of known analytical grade and distilled or demineralised water. 5.2 Hydrochloric acid, = 1,19 g/ml 5.3 Nitric acid, = 1, 4 g/ml 5.4 Perchloric acid, = 1,6 g/ml 5.5 Sulphuric acid, = 1,83
26、 g/ml 5.6 Chloroacetic acid 5.7 Sodium hydroxide EN 12441-10:2004 (E) 5 5.8 Sulphuric acid, (1+1) Carefully add 1 part volume of sulphuric acid (5.5) to 1 part volume of water. 5.9 Sulphuric acid, 2M Carefully pour 110 ml of sulphuric acid (5.5) into water and dilute to a final volume of 1 litre. 5.
27、10 Aqua regia Mix 3 part volumes of hydrochloric acid (5.2) with 1 part volume of nitric acid (5.3). 5.11 Pure titanium 5.12 Titanium oxalate potassium, pure and dry K 2 TiO(COO) 4 2H 2 O 5.13 Chromotropic acid, 60 g/l (fresh solution) 5.14 Buffer solution, pH 2,9 (fresh solution) Dissolve separatel
28、y in 600 ml beakers, each with about 400 ml of water: 236 g of chloracetic acid (5.6); 50 g of sodium hydroxide (5.7). Transfer both solutions quantitatively to a 1 litre volumetric flask. Dilute to the mark with water and mix. 5.15 Ascorbic acid, 20 g/l (fresh solution) 5.16 Titanium, 1 g/l standar
29、d solution Introduce either 1,848 g of titanium oxalate potassium (5.12), either 0,250 g of pure titanium (5.11), weighted to the nearest 0,001 g, into a 400 ml beaker. Add 50 ml of sulphuric acid (5.8). Heat gently to complete dissolution. Cool to room temperature and transfer to a 250 ml volumetri
30、c flask. Dilute to the mark with water and mix. 1 ml of this solution contains 1 mg of titanium. 5.17 Titanium, 25 mg/l standard solution (fresh solution) Transfer 25 ml of the titanium standard solution (5.16) to a 1 litre volumetric flask. Dilute to the mark with water and mix. 1 ml of this soluti
31、on contains 0,025 mg of titanium. 5.18 Potassium dichromate, dried at 105 C. 5.19 Acetone 5.20 Diphenyl carbazide, 10 g/l (fresh solution) Dissolve 1 g of diphenyl carbazide in 100 ml of acetone (5.19). EN 12441-10:2004 (E) 6 5.21 Chromium, 500 mg/l standard solution Introduce 1,414 5 g of potassium
32、 dichromate (5.18) weighted to the nearest 0,000 5 g into a 400 ml beaker. Add 200 ml of water and 50 ml of sulphuric acid (5.8). Heat gently to complete dissolution. Cool to room temperature and transfer to a 1 litre volumetric flask. Dilute to the mark with water and mix. 1 ml of this solution con
33、tains 0,5 mg of chromium. 5.22 Chromium, 25 mg/l standard solution Transfer 25 ml of the chromium standard solution (5.21) to a 500 ml volumetric flask. Dilute to the mark with water and mix. 1 ml of this solution contains 0,025 mg of chromium. 6 Apparatus 6.1 General All glassware used for the prep
34、aration of the solutions and for the implementation of the method shall be cleaned with boiling aqua regia (5.10) prior to use. 6.2 Specific equipment In addition to standard laboratory apparatus, a spectrophotometer, set at a wavelength of 540 nm for chromium, 470 nm for titanium and using 1 cm opt
35、ical cells shall be used. NOTE The dilution and aliquot parts defined in this document 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
36、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. 8.3 Preparation of the test solut
37、ion 8.3.1 General Introduce the test portion (8.1) into a 250 ml beaker fitted with a watch-glass and carefully add 5 ml of hydrochloric acid (5.2). Complete the dissolution by adding 2 ml of nitric acid (5.3). Add 10 ml of perchloric acid (5.4) and heat by raising the temperature gradually in order
38、 to allow complete oxidation to Cr (VI), until strong white fumes are evolved. Cool to room temperature, add 50 ml of water and heat gradually to boiling to dissolve salts. Cool to room temperature and transfer quantitatively to a 200 ml volumetric flask. Dilute to the mark with water and mix. EN 12
39、441-10:2004 (E) 7 8.3.2 Chromium determination Transfer a 10 ml aliquot of the sample solution (8.3) to a 200 ml volumetric flask and add successively: 5 ml of sulphuric acid (5.9); 80 ml of water; 1 ml of diphenyl carbazide solution (5.20). Dilute to the mark with water and mix. Wait for 15 minutes
40、, then measure the absorbance of this solution against the blank test solution (8.2) in 1 cm cells using the spectrophotometer (6.2) set at a wavelength of 540 nm. 8.3.3 Titanium determination Transfer a 10 ml aliquot of the sample solution (8.3) to a 200 ml volumetric flask and add successively: 10
41、 ml of ascorbic acid (5.15); 2 ml of chromotropic acid (5.13); 20 ml of buffer solution (5.14). Dilute to the mark with water and mix. Wait for 15 minutes, then measure the absorbance of this solution against the blank test solution (8.2) in 1 cm cells using the spectrophotometer (6.2) set at a wave
42、length of 470 nm. 8.4 Calibration NOTE The following is valid for 1 cm cells and for 0 mg, 0,025 mg, 0,05 mg, 0,10 mg, 0,15 mg, 0,20 mg and 0,25 mg of chromium or titanium corresponding to contents (mass fractions) in the test portion of 0 %, 0,05 %, 0,1 %, 0,2 %, 0,3 %, 0,4 % and 0,5 %. It is neces
43、sary to apply the appropriate modifications in the case of cells of different lengths. 8.4.1 Chromium Introduce into a series of 200 ml volumetric flasks, 0,00 ml, 1,00 ml, 2,00 ml, 4,00 ml, 6,00 ml, 8,00 ml and 10,00 ml of the chromium standard solution (5.22) and proceed as specified in 8.3.2. Est
44、ablish a calibration graph by plotting the measured absorbances of the calibration solutions against their respective contents (mass fractions). 8.4.2 Titanium Introduce into a series of 200 ml volumetric flasks, 0,00 ml, 1,00 ml, 2,00 ml, 4,00 ml, 6,00 ml, 8,00 ml and 10,00 ml of the titanium stand
45、ard solution (5.17) and proceed as specified in 8.3.3. Establish a calibration graph by plotting the measured absorbances of the calibration solutions against their respective contents (mass fractions). EN 12441-10:2004 (E) 8 9 Calculation and expression of results 9.1 Method of calculation Determin
46、e from the measured absorbances of the test solutions the associated amount of chromium or titanium from the calibration graphs (8.4.1 or 8.4.2). If a number of determinations are carried out then a mean of all results shall be determined by adding the individual results together and by dividing by
47、the number of individual results. The results shall be expressed as specified in EN 1774 and EN 12844. 9.2 Precision A planned trial of this method was carried out by 10 laboratories, using 1 sample with 1 level of chromium content and 1 level of titanium content, each laboratory making three determ
48、inations of each element content in this sample (see Notes 1 and 2) NOTE 1 Two of the three determinations were carried out under repeatability conditions as defined in ISO 5725-1; 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 same operator as in Note 1, using the same apparatus and different cal
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