1、Zinc and zinc alloys Chemical analysis Part 3: Determination of lead, cadmi rn and copper - Flame atomic absorption spectrometric method The European Standard EN 12441-3:2001 has the status of a British Standard ICs 77.120.60; 77.040.30 BS EN 1244 1 -3 12002 NO COPYING WITHOUT BSI PERMISSION EXCEPT
2、AS PERMITTED BY COPYRIGHT LAW BS EN 12441-312002 Amd. No. National foreword Date Comments This British Standard is the official English language version of EN 12441-3:2001. It supersedes BS 3630-7:1967, BS 3630-8:1971, BS 3630-9:1969, BS 3630-13:1972 and BS 3630-14:1972 which are withdrawn. The UKpa
3、rticipation in its preparation was entrusted by Technical Committee NFE/8, Zinc and zinc alloys, to Subcommittee NFE/8/4, Sampling and analysis of zinc and zinc alloys, which has the responsibility to: - - aid enquirers to understand the text; present to the responsible European committee any enquir
4、ies on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developments and promulgate them in the UK. - A list of organizations represented on this subcommittee can be obtained on request to its secretary. Cr oss-r e fer enc e
5、s The British Standards which implement international or European publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue
6、. 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 not of itself confer immunity from legal obligations. This British Standard. having - been pr
7、epared under the direction of the Engineering Summary Of pages Sector Policv and Stratew This document comprises a front cover, an inside front cover, the EN title page, -_ Committee, was published pages 2 to 12. an inside back cover and a back cover. under the authority of the Standards policy and
8、Strategy Committee on 23 January 2002 The BSI copyright date displayed in this document indicates when the document was last issued. O BSI 23 January 2002 ISBN0 580 38163 3 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12441-3 October 2001 ICs 77.040.30; 77.120.60 English version Zinc and zin
9、c alloys - Chemical analysis - Part 3: Determination of lead, cadmium and copper - Flame atomic absorption spectrometric method Zinc et alliages de zinc - Analyse chimique - Partie 3: Dosages du plomb, du cadmium et du cuivre - Mthode par spectromtrie dabsorption atomique dans la flamme Zink und Zin
10、klegierungen - Chemische Analyse - Teil 3: Bestimmung von Blei, Cadmium und Kupfer - FAAS- Verfahren This European Standard was approved by CEN on 11 August 2001. CEN members are bound to comply with the CENKENELEC Internal Regulations which stipulate the conditions for giving this European Standard
11、 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 Management Centre or to any CEN member. This European Standard exists in three official versions (English, French, Germa
12、n). 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 the official versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finla
13、nd, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION EUROPISCHES KOMITEE FR NORMUNG COMIT EUROPEN DE NORMALISATION Management Centre: rue de Stassart, 36 B-1050 Brussels
14、O 2001 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12441-3:2001 E EN 12441-3:2001 (E) Contents Page Foreword 3 10 Scope 4 Normative references 4 Terms and definitions 4 Principle 4 Reagents . 5 Apparatus . 7 Sampling . 7 Calcul
15、ation and expression of results . 11 Procedure . 7 Test report 11 2 EN 12441-3:2001 (E) 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 European Standard shall be given the status of a nation
16、al 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 program of work, Technical Committee CEN/TC 209 entrusted CEN/TC 209/WG 6 “Methods of analysis and tes
17、ting” with the preparation of the following document: prEN 12441-3, Zinc and zinc alloys - Chemical analysis - Part 3: Determination of lead, cadmium and copper - Flame atomic absorption spectrometric method. This standard is part of a series of eleven standards. The other standards are: - Part I :
18、Determination of aluminium in zinc alloys - Titrimetric method - Part 2 : Determination of magnesium in zinc alloys - Flame atomic absorption spectrometric method - Part 4 : Determination of iron in zinc alloys - Spectrophotometric method - Part 5 : Determination of iron in primary zinc - Spectropho
19、tometric method - Part 6 : Determination of aluminium and iron - Flamme atomic absorption spectrometry method - Part 7 : Determination of tin - Flame atomic absorption spectrometric method after extraction - Part 8 : Determination of tin in secondary zinc - Flame atomic absorption spectrometric meth
20、od - 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 I I : Determination of silicon in zinc alloys - Spectrophotometric method According to the CENKENEL
21、EC 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, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Swit
22、zerland and the United Kingdom. 3 EN 12441-3:2001 (E) 1 Scope This European Standard specifies a flame atomic absorption spectrometry method for the determination of lead, copper and cadmium in zinc and zinc alloys. It is applicable to the products specified in EN 988, EN 1179, EN 1774, EN 12844 and
23、 prEN 13283. It is suitable for the determination of lead contents (mass fractions) between 0,000 5 % and 2,5 %, cadmium contents (mass fractions) between 0,000 5 % and 0,3 %, and copper mass fractions between 0,000 5 % and 4 %. 2 Normative references This European Standard incorporates by dated or
24、undated reference, provisions from other publications. These normative references are cited at the appropriate places in the 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
25、when incorporated in it by amendment or revision. For undated references the latest edition of the publication referred to applies (including amendments). EN 988, Zinc and zinc alloys - Specifications for rolled flat products for building. EN 1 179, Zinc and zinc alloys - Primary zinc. EN 1774, Zinc
26、 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. prEN 13283, Zinc and zinc alloys - Secondary zinc. 3 Terms and definitions For the purposes of this sta
27、ndard, the terms and definitions given in EN 12060 and the following apply. 3.1 flame atomic absorption spectrometry measurement of the absorption of electromagnetic radiation, emitted by an element at a determined wavelength, by an absorbent medium (flame) formed of atoms of the same element that a
28、re in the ground state. Each element absorbs radiation of specific wavelengths and the intensity of the absorbed radiation is proportional to the concentration of said element 4 Principle A sample of the metal or alloy is dissolved in a mixture of hydrochloric acid and nitric acid and, after adequat
29、e dilution and atomization of the solution into an air-acetylene flame, the content of the particular element is determined by flame atomic absorption spectrometry. Sample(s) of secondary zinc containing tin are dissolved in hydrochloric acid/hydrogen peroxide. NOTE For lead contents (mass fractions
30、) between 0,000 5 % and 0,005 %, the determination could be preceded by an enrichment of the lead by simultaneous precipitation with copper sulphide as a trace impurity scavenger from ammoniacal solution in the presence of ammonium fluoride, a specified amount of thioacetamide being used as precipit
31、ating agent. 4 EN 12441-3:2001 (E) 5 Reagents 5.1 General During the test, use only reagents of known or analytical grade and distilled or demineralized water. 5.2 Hydrochloric acid, p = 1,19 g/ml 5.3 Nitric acid, p = 1,4 g/ml 5.4 Hydrochloric acid-nitric acid mixture Mix 180 volumes of hydrochloric
32、 acid (5.2) with 4 volumes of nitric acid (5.3). This mixture shall be freshly prepared just before use 5.5 Hydrochloric acid (1 + 6) Mix 1 volume of hydrochloric acid (5.2) with 6 volumes of water. 5.6 Zinc powder Zinc powder of particle size less than 60 pm, prepared from zinc having a purity of n
33、ot less than 99,995 %. 5.7 Zinc chloride solution, 200 g /I Introduce 200 g of zinc (minimum purity 99,995 %) into a 2 I beaker. Add 100 ml of water and 700 ml of hydrochloric acid (5.2) carefully in small amounts to control the rate of reaction. After dissolution evaporate carefully to a syrupy con
34、sistency. After cooling, take up with about 800 ml water and warm gently to dissolve any salts. Add 20 g of zinc powder (5.6) and shake from time to time for not less than 30 min. Transfer into a 1 I volumetric flask, dilute to the mark with water and mix. Allow to settle and filter the solution wit
35、hout washing the residue. Store in a polyethylene bottle. 1 ml of this solution contains approximately 200 mg of zinc. NOTE If zinc with a purity of not less than 99,9999 % is used, the treatment with zinc powder may be omitted. 5.8 Lead, cadmium or copper, 1 g/l solutions Introduce 0,500 g of lead,
36、 cadmium or copper (in all cases with a purity of not less than 99,9 %) into a 100 ml beaker fitted with a watch-glass, and add about 10 ml of water. Dissolve by carefully adding 5 ml of nitric acid (5.3). After dissolution, heat the solution until no further nitrous gas is evolved. Cool and transfe
37、r to a 500 ml volumetric flask, dilute to the mark with water and mix. 1 ml of this solution contains 1 mg of lead, cadmium or copper. 5.9 Standard solutions of lead, cadmium or copper Transfer 25,OO ml of each of the solutions, prepared as described in 5.8, into a series of 1 O00 ml volumetric flas
38、ks. Dilute to the mark with water and mix. 1 ml of each of these solutions contains 0,025 mg of lead, cadmium or copper. 5.10 Hydrochloric acid (1 + 1) Mix 1 volume of hydrochloric acid (5.2) with 1 volume of water 5 EN 12441-3:2001 (E) 5.1 1 Ammonia solution, p = 0,91 g/ml 5.12 Perchloric acid, 60
39、% (mass fraction) 5.1 3 Chloroform 5.14 Hydrogen peroxide, 30 % (mass fraction) 5.15 Copper, 5 g/l solution Dissolve 1 g of high purity copper containing not more than 5 pg/g of lead in 15 ml of hydrochloric acid solution (1 + 1) (5.10). Add hydrogen peroxide (5.14) dropwise and heat gently on a hot
40、plate until dissolution. Evaporate to a syrupy consistency. Take up in water and transfer quantitatively to a 200 ml volumetric flask. Dilute to the mark with water and mix. 1 ml of this solution contains 5 mg of copper 5.1 6 Thioacetamide solution Fresh solution, prepared immediately before use by
41、dissolving 300 mg of thioacetamide in water and made up to 100 ml. 5.17 Dithizone solution Dissolve 40 mg of dithizone in 1 I of chloroform (5.13). Protect this solution from light and keep it in a brown glass bottle. 5.18 Purified ammonium fluoride solution Dissolve 50 g of ammonium fluoride, NH4F,
42、 in about 300 ml of water in a plastic beaker. Adjust the pH of the solution to 73 f 0,l using ammonia solution (5.11), and transfer to a 500 ml shaking funnel. Now shake, while adding dithizone solution (5.17) in 15 ml portions, discarding the extract each time until the final extract retains the p
43、ure green colour of the dithizone solution. Remove residual dithizone by shaking several times with 15 ml of pure chloroform (5.13). Drain the purified ammonium fluoride solution into a plastic beaker and adjust its pH value to between 9,8 and 10,O with ammonia solution (5.1 1). Transfer the solutio
44、n to a 500 ml volumetric flask, and make up to the mark with water. Mix and transfer to a plastic bottle for storage. 5.19 Aqua regia Mix 3 volumes of hydrochloric acid (5.2) with 1 volume of nitric acid (5.3). 5.20 Aluminium, 50 g/l solution Introduce 50 g of aluminium, with a minimum purity of 99,
45、995 % and free of lead, cadmium and copper into a 1 I beaker. Add 200 ml of water and 200 ml of hydrochloric acid (5.2). After dissolution evaporate carefully to a syrupy consistency. After cooling, take up with about 800 ml of water and transfer to a 1 I volumetric flask. Add 20 g of aluminium-turn
46、ings and shake from time to time for not less than 60 minutes. Transfer to a 1 I volumetric flask, dilute to the mark with water and mix. Allow to settle and filter the solution without washing the residue. Store in a polyethylene bottle. 1 ml of this solution contains approximately 50 mg of alumini
47、um. 6 EN 12441-3:2001 (E) 6 Apparatus 6.1 General All glassware used for the preparation of the solutions and for the implementation of the method shall be cleaned with boiling aqua regia (5.19) prior to use. 6.2 Specific equipment In addition to standard laboratory apparatus, the following shall be
48、 used: a) atomic absorption spectrometer, equipped with a premix burner, with facilities for using the oxidizer-fuel combination of air-acetylene ; NOTE path length within the flame should be between 5 cm and 10 cm. The excitation source should be operated in accordance with the manufacturers recomm
49、endations. The optical b) pH meter; c) membrane filtration apparatus, with cellulose nitrate membrane filter having a diameter of 50 mm or 30 mm and a pore size of 0,45 pm or 0,6 pm. 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 10 g of the test sample to the nearest 0,Ol g. 8.2 Preparation of the test sample solution 8.2.1 Introduce the test portion (8.1) into a 250 ml beaker fitted with a watch-glass and dissolve by carefully adding 60 ml of the acid mixture (5.4). Evaporate carefully
