1、BRITISH STANDARD BS EN 10212:1996 Chemical analysis of ferrous materials Determination of arsenic in steel and iron Spectrophotometric method The European Standard EN10212:1995 has the status of a BritishStandard ICS71.040.40BSEN10212:1996 This BritishStandard, having been prepared under the directi
2、onof the Engineering SectorBoard, was published underthe authority of the Standards Board and comes intoeffect on 15February1996 BSI11-1999 The following BSI references relate to the work on this standard: Committee reference ISE/18 Draft for comment91/38468DC ISBN 0 580 25440 2 Committees responsib
3、le for this BritishStandard The preparation of this BritishStandard was entrusted to Technical Committee ISE/18, Sampling and analysis of iron and steel, upon which the following bodies were represented: BCIRA British Iron and Steel Producers Association Ministry of Defence Welding Institute Amendme
4、nts issued since publication Amd. No. Date CommentsBSEN10212:1996 BSI 11-1999 i Contents Page Committees responsible Inside front cover National foreword ii Foreword 2 Text of EN10212 3 List of references Inside back coverBSEN10212:1996 ii BSI 11-1999 National foreword This BritishStandard has been
5、prepared by Technical Committee ISE/18 and is the English language version of EN10212:1995, Chemical analysis of ferrous materials Determination of arsenic in steel and iron Spectrophotometric method, published by the European Committee for Standardization (CEN). It was produced as a result of inter
6、national discussions in which the UnitedKingdom took an active part. 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 immun
7、ity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, pagesi andii, theEN title page, pages2 to8, an inside back cover and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be ind
8、icated in the amendment table on the inside front cover.EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN10212 March1995 ICS71.040.40 Descriptors: Iron and steel products, steels, cast iron, chemical analysis, determination of content, arsenic, spectrophotometric analysis English version Chemical
9、 analysis of ferrous materials Determinationofarsenic in steel and iron Spectrophotometric method Analyse chimique des matriaux sidrurgiques Dosage de larsenic dans les aciers et les fontes Mthode spectrophotomtrique Chemische Analyse von Eisenwerkstoffen Bestimmung von Arsen in Stahl und Eisen mitt
10、els Spektralphotometrie This European Standard was approved by CEN on 1995-02-06. 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 any alteration. Up-to-date lists and
11、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 by translation under the responsibili
12、ty 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, Luxembourg, Netherlands, Norway, Portu
13、gal, Spain, Sweden, Switzerland and UnitedKingdom. CEN European Committee for Standardization Comit Europen de Normalisation Europisches Komitee fr Normung Central Secretariat: rue de Stassart 36, B-1050 Brussels 1995 All rights of reproduction and communication in any form and by any means reserved
14、 in allcountries to CEN and its members. Ref. No. EN10212:1995 EEN10212:1995 BSI 11-1999 2 Foreword This European Standard was prepared by Technical Committee ECISS/TC20, Methods of chemical analysis, the secretariat of which is held by SIS. The European Standard shall be given the status of a natio
15、nal standard, either by publication of an identical text or by endorsement, at the latest by September1995, and conflicting national standards shall be withdrawn at the latest by September1995. According with the CEN/CENELEC Internal Regulations, the following countries are bound to implement this E
16、uropean Standard: Austria, Belgium, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland, UnitedKingdom. Contents Page Foreword 2 1 Scope 3 2 Normative references 3 3 Principle 3 4 Reagents 3 5 Apparatus 3 6 Samplin
17、g 4 7 Procedure 4 8 Expression of results 6 9 Test report 6 Annex A (informative) Precision data 7 Figure 1 Arsine evolution and absorption apparatus 4 Table 1 Calibration solutions 5 Table A.1 Certified reference materials tested 7EN10212:1995 BSI 11-1999 3 1 Scope This European Standard specifies
18、a spectrophotometric method for the determination of arsenic in steel and iron. The method is applicable toall types of steel and iron with arsenic contents from0,001% to0,08%(m/m). 2 Normative references This European Standard incorporates by dated or undated references, provisions from other publi
19、cations. 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 when incorporated in it by amendment or revisio
20、n. For undated references the latest edition of the publication referred to applies. EURONORM18:1979, Selection and preparation of samples and test pieces for steel and iron and steel products. 3 Principle Dissolution of a test portion in a mixture of nitric and hydrochloric acids followed by evapor
21、ation to dryness and prolonged heating of the dried residue. Extraction of the residue with acid, reduction of the arsenic (As V to As III) by addition of potassium iodide, ascorbic acid and tin (II) chloride. Conversion of the arsenic to arsenic hydride (arsine) with zinc. Absorption of the evolved
22、 arsine in a solution of silver diethyldithiocarbamate and1-ephedrin in trichloromethane. Spectrophotometric measurement of the reddish-violet coloured colloid at a wavelength between500nm and520nm. 4 Reagents During the analysis, use only reagents of recognized analytical quality and only distilled
23、 water or water of equivalent purity. 4.1 Iron, of high purity, free of arsenic or of known low arsenic content. 4.2 Zinc, of high purity, free of arsenic or of known low arsenic content. Zinc shot,0,5mm to2mm, and zinc pellets, approximately5mm in diameter. 4.3 Hydrochloric acid, approximately 1,19
24、g/ml. 4.4 Sulfuric acid, approximately 1,84g/ml, diluted1+1. 4.5 Hydrochloric-nitric acid mixture. Add65ml nitric acid, approximately 1,40g/ml, to100ml water; add the resulting diluted acid to60ml hydrochloric acid(4.3) and mix. 4.6 Absorption solution. Dissolve1,25g of silver diethyldithiocarbamate
25、 (C 5 H 10 AgNS 2 ) and0,825g of1-ephedrin in approximately400ml of trichloromethane (chloroform) in a500ml volumetric flask. Dilute to the mark with trichloromethane and mix. After preparation a small residue may develop. Filter the solution after at least20h and store the solution in an amber colo
26、ured bottle. The solution can be used after the filtration for at least3 months. NOTEThe peak wavelength of the silver colloid may vary with the quality of the reagent and should be determined with each new batch of reagent. 4.7 Ascorbic acid,100g/l solution. This solution shall be freshly prepared
27、each day. 4.8 Potassium iodide,150g/l solution. This solution shall be freshly prepared each day. 4.9 Tin (II) chloride,400g/l in hydrochloric acid solution. Dissolve20g of tin (II) chloride in approximately40ml of hydrochloric acid(4.3). Transfer to a50ml volumetric flask, dilute to the mark with h
28、ydrochloric acid(4.3) and mix. This solution shall be freshly prepared each day. 4.10 Lead acetate wool. Impregnate cotton wool with lead acetate trihydrate solution,(10g/l), squeeze out the excess solution and dry the wool at105 C for several hours. 4.11 Arsenic standard solution, corresponding to5
29、4g of arsenic per ml. Dissolve0,3301g of arsenic trioxide, dried at105 C, in20ml sodium hydroxide solution(8g/l). Transfer to a1000ml volumetric flask, dilute to the mark with water and mix. Transfer20,0ml of this solution to a1000ml volumetric flask, dilute to the mark with water andmix. 5 Apparatu
30、s Ordinary laboratory equipment and 5.1 A spectrophotometer, suitable for measuring the absorbance of the solution at a wavelength of500nm to520nm(see4.6), together with cells of40mm and10mm optical path length. 5.2 Apparatus for the evolution and absorption of arsine, as shown in Figure 1. NOTEAppr
31、oximate dimensions are shown in the figure. Important parameters are an adequate depth of immersion and sufficient free space around the capillary to allow the bubbles to rise without agglomeration. If these conditions are satisfied, variations in the apparatus should be permissible. It is essential
32、 that the arsine absorption is complete. This may be verified initially for a given piece of apparatus by coupling a second absorption vessel in series with the first.EN10212:1995 4 BSI 11-1999 6 Sampling Sampling shall be carried out in accordance with EURONORM18. 7 Procedure 7.1 Test portion Weigh
33、, to the nearest0,0001g, a test portion of0,1g 0,005g. NOTEFor coarse samples, where the weighing of0,1g may be inconvenient or where a more representative sample is required, a larger portion may be dissolved in the acid-mixture(4.5). After the prolonged heating period and the extraction of the res
34、idue in hydrochloric acid(4.3), an aliquot equivalent to0,1g shall be taken and treated with10ml of sulfuric acid(4.4) as specified in7.3.1. 7.2 Blank test With each analytical run, carry out the calibration procedure as specified in7.4. The zero member of the calibration series provides automatic c
35、ompensation for arsenic in the reagents see7.4.3 and the note. NOTEThe dimensions given are the approximate values only. Figure 1 Arsine evolution and absorption apparatusEN10212:1995 BSI 11-1999 5 7.3 Determination 7.3.1 Preparation of the test solution Transfer the test portion(7.1) to a100ml coni
36、cal beaker, add10ml of hydrochloric-nitric acid mixture(4.5), cover the beaker with a watch-glass and digest until solvent action ceases. Rinse and remove the watch-glass and heat carefully until all liquid has been evaporated. Continue to heat the dried residue at a temperature of300 C to350 C for
37、a period of about3h. Cool, add10ml of hydrochloric acid(4.3) and heat to dissolve the residue. Add10ml of sulfuric acid(4.4) and heat carefully to remove oxides of nitrogen. Continue heating until copious white fumes of sulfur trioxide are evolved. Cool, dilute with water to40ml, warming if necessar
38、y to dissolve the precipitated sulfates. 7.3.2 Reduction of arsenic (V) to arsenic (III) Cool and add in the following order,5ml of potassium iodide solution(4.8),5ml of ascorbic acid solution(4.7) and3ml of tin (II) chloride solution(4.9). Allow to stand for5min. NOTEIn the case of an unalloyed ste
39、el, the solution, at this stage should be virtually colourless. Coloration is indicative of incomplete removal of nitric acid. Optimum conditions for fuming are best decided in the individual laboratory, with due regard being taken of the temperature variations occurring across hot plate surfaces an
40、d to spurting if the temperature rises too fast. A final hot plate temperature of approximately200 C to240 C has been found to be satisfactory. 7.3.3 Evolution of arsine and development of the colour Transfer the solution to the evolution flask(5.2), rinsing with10ml to20ml of water. Dry the neck of
41、 the flask, add a mixture of3g of zinc shot and3g of zinc pellets(4.2) and immediately connect the flask to the delivery tube by means of the ground glass stopper. As evolution commences, immerse the delivery tube into20ml of the absorption solution(4.6) contained in an absorption tube with a20,0ml
42、mark.(Seethe figure.) NOTE 1It is important to avoid crystallization at the tip of the capillary with the danger of blockage and pressure build-up in the apparatus. Recommended practice is to lower the delivery tube slowly into the absorption solution (or conversely, if more convenient, to raise the
43、 absorption vessel) as evolution commences, so that the inside of the capillary remains dry. At the end of the experiment, the bore at the tip of the capillary should be cleaned immediately with a fine wire and rinsed with trichloromethane to prevent adhesion of dried salts. A multihole bubbler coul
44、d be advantageous in minimizing the risk of blocking, but being more difficult to standardize, may increase the risk of arsine carry over. NOTE 2During the experiment there is inevitably a small release of trichloromethane vapour. It is recommended that the apparatus is placed in a fume cupboard or
45、is otherwise adequately ventilated. Allow the evolution of arsine to proceed for30min. Remove the absorption tube from the evolution apparatus and dilute to the20ml mark on the tube with trichloromethane to make up for loss by evaporation. Mix the solution thoroughly. 7.3.4 Spectrophotometric measur
46、ement Carry out the spectrophotometric measurement at the peak wavelength(500nm to520nm,see4.6) after having set the spectrophotometer(5.1) to zero absorption in relation to water. Use40mm cells for arsenic contents up to0,02% and10mm cells for contents larger than0,02%. Control the solution tempera
47、ture at the time of measurement to be20 C 1 C. Convert the absorbance readings of the test solution to micrograms of arsenic by reference to the appropriate calibration graph(see7.4). 7.4 Establishment of the calibration graph NOTEIt is essential that the calibration graph is established for each se
48、ries of samples. 7.4.1 Preparation of the calibration solutions Weigh0,1g portions of iron(4.1) into a series of100ml beakers. From a burette make additions ofarsenic standard solution(4.11) as shown inTable 1. Table 1 Calibration solutions Continue as described in7.3.1, 7.3.2 and7.3.3. 7.4.2 Spectr
49、ophotometric measurements Carry out the spectrophotometric measurements according to the method described in7.3.4 after having adjusted the spectrophotometer(5.1) to zero absorbance in relation to water. 7.4.3 Plotting the calibration graph Prepare calibration graphs(10mm and40mm cells) by plotting the absorbance readings against micrograms of arsenic in the measuring solution. NOTEUsing the calibration graphs as described above results in an automatic correction of the arsenic in the blank. Arsenic standard solution(4.11)
