1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 10071:2012Chemical analysis of ferrousmaterials Determinationof manganese in steels andirons Electrometric titrationmethodBS EN 10071:2012 BRITISH STANDARDNational foreword
2、This British Standard is the UK implementation of EN 10071:2012. Itsupersedes BS EN 10071:1991 which is withdrawn.The UK participation in its preparation was entrusted to TechnicalCommittee ISE/102, Methods of Chemical Analysis for Iron and Steel.A list of organizations represented on this committee
3、 can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2012. Published by BSI StandardsLimited 2012ISBN 978 0 580 77391 4ICS 77.040.30; 77.
4、080.01Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 October 2012.Amendments issued since publicationDate Text affectedBS EN 10071:2012EUROPEAN STANDARD NORME
5、EUROPENNE EUROPISCHE NORM EN 10071 October 2012 ICS 77.040.30 Supersedes EN 10071:1989English Version Chemical analysis of ferrous materials - Determination of manganese in steels and irons - Electrometric titration method Analyse chimique des matriaux ferreux - Dtermination du manganse dans les aci
6、ers et les fontes - Mthode par titrage lectromtrique Chemische Analyse von Eisenwerkstoffen - Bestimmung von Mangan in Stahl und Eisen - Elektrometrisches Titrierverfahren This European Standard was approved by CEN on 17 August 2012. CEN members are bound to comply with the CEN/CENELEC Internal Regu
7、lations 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 CEN-CENELEC Management Centre or to any CEN memb
8、er. 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 CEN-CENELEC Management Centre has the same status as the official versions. C
9、EN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland,
10、 Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and
11、 by any means reserved worldwide for CEN national Members. Ref. No. EN 10071:2012: EBS EN 10071:2012EN 10071:2012 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Principle 44 Reagents .45 Apparatus .66 Sampling .67 Procedure .68 Expression of results 79 Test report 8BS EN 10071:2012
12、EN 10071:2012 (E) 3 Foreword This document (EN 10071:2012) has been prepared by Technical Committee ECISS/TC 102 “Methods of analysis for iron and steel”, the secretariat of which is held by SIS. This European Standard shall be given the status of a national standard, either by publication of an ide
13、ntical text or by endorsement, at the latest by April 2013, and conflicting national standards shall be withdrawn at the latest by April 2013. Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. CEN and/or CENELEC shall not be held re
14、sponsible for identifying any or all such patent rights. This document supersedes EN 10071:1989. In comparison with EN 10071:1989, the following significant technical change was made: Clause 3, Principle, rewording of the third sentence in order to correct the erroneous mention of “pyrophosphoric ir
15、ons”. According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, Franc
16、e, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 10071:2012EN 10071:2012 (E) 4 1 Scope This European Standard specifies an e
17、lectrometric titration method for the determination of manganese in steels and irons. The method is applicable to unalloyed, low alloy or alloyed steels and to irons with manganese contents greater than or equal to 0,5 % (m/m). 2 Normative references The following documents, in whole or in part, are
18、 normatively referenced in this document and are indispensable for its application. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 648, Laboratory glassware Single-volume pipettes
19、(ISO 648) EN ISO 1042, Laboratory glassware One-mark volumetric flasks (ISO 1042) EN ISO 14284, Steel and iron Sampling and preparation of samples for the determination of chemical composition (ISO 14284) 3 Principle Dissolution of the test portion with appropriate acids, followed by a partial neutr
20、alisation of the acids with sodium hydrogen carbonate. Precipitation of the interfering cations with zinc oxide. Titration of Mn (II) with a potassium permanganate solution, in a pyrophosphoric medium at a pH of about 6,5. The oxidation-reduction reaction oxidation of Mn (II) to Mn (III) is controll
21、ed by an electrometric measurement. 4 Reagents During the analysis, use only reagents of recognised analytical grade. 4.1 Water, free from reducing compounds. For each 1 000 ml of water add 6 ml of sulphuric acid (20= 1,84 g/ml) and boil. Add a few crystals of sodium periodate and maintain the boili
22、ng for about 10 min. Cool and transfer into an appropriate vessel. 4.2 Zinc oxide, free from compounds which can reduce the permanganate ions. 4.3 Nitric acid solution, 1 + 1. Add 500 ml of nitric acid (20= 1,40 g/ml) to 500 ml of water (4.1). 4.4 Hydrochloric acid solution, 1 + 1. Add 500 ml of hyd
23、rochloric acid (20= 1,19 g/ml) to 500 ml of water (4.1). BS EN 10071:2012EN 10071:2012 (E) 5 4.5 Aqua regia. Mix three volumes of hydrochloric acid (20= 1,19 g/ml) with one volume of nitric acid (20= 1,40 g/ml). 4.6 Sodium hydrogen carbonate, saturated solution at room temperature. NOTE The concentr
24、ation of the saturated solution corresponds to about 100 g/l NaHCO3, in water (4.1). 4.7 Sodium pyrophosphate solution, 120 g/l. Dissolve 120 g of hydrated sodium pyrophosphate (Na4P2O7. 10 H2O) in a one-litre beaker with hot water (4.1). After cooling, transfer this solution into a 1 000 ml one-mar
25、k volumetric flask. Dilute to the mark with water (4.1) and mix. NOTE The temperature shall not exceed 70 C. 4.8 Manganese standard solution, 0,500 g/l Mn. Weigh (1,4385 0,001) g of potassium permanganate (KMnO4) and transfer it into a 500 ml conical flask. Dissolve with 40 ml of hydrochloric acid (
26、4.4) and then heat the solution until dryness. Add 5 ml of hydrochloric acid (4.4), 100 ml of water (4.1) and mix. Transfer the solution quantitatively into a 1 000 ml one-mark volumetric flask, cool, dilute to the mark with water (4.1) and mix. 1 ml of this solution contains 0,500 mg of Mn. 4.9 Pot
27、assium permanganate standard solution, about 0,002 2 mol/l. 4.9.1 Preparation of the solution. Dissolve approximately 0,36 g of potassium permanganate with 1 000 ml of water (4.1) and allow the solution to stand out of the light, for at least two weeks. Filter through a glass wool or a sintered glas
28、s filter, transfer the filtrate into a brown glass bottle and mix. 4.9.2 Standardization of the solution. Transfer 350 ml of the sodium pyrophosphate solution (4.7) into a 600 ml beaker. With calibrated pipettes or a burette, add 30 ml of the manganese standard solution (4.8). Mix carefully and then
29、 add small amounts of nitric acid (4.3) in order to set up the pH to about 6,5. NOTE The pH setting up can be controlled either by means of a pH-meter (5.2) or by means of a pH indicator paper (4.10). Titrate with the potassium permanganate standard solution (4.9) and determine the end point by mean
30、s of an electrometric measurement. 4.9.3 Calculation of the titre of the solution. The manganese concentration, 1C , of the potassium permanganate standard solution (4.9), expressed in mg/ml is given by the Formula (1): 1130 x 0,5000CV= (1) where BS EN 10071:2012EN 10071:2012 (E) 6 1V is the volume,
31、 expressed in millilitres, of the potassium permanganate standard solution (4.9) used for the titration. 4.10 pH indicator paper, range 5 to 7. 5 Apparatus All volumetric glassware shall be Class A and calibrated, in accordance with EN ISO 648 or EN ISO 1042 as appropriate. 5.1 Magnetic stirrer. 5.2
32、 pH-meter, fitted with glass electrode and a calomel electrode. 5.3 Potentiometer, fitted with platinum electrode and a calomel electrode. 6 Sampling Sampling shall be carried out in accordance with EN ISO 14284 or an appropriate national standard for steel and iron. 7 Procedure 7.1 Test portion Wei
33、gh, to the nearest 0,001 g, 1,25 g of the test sample. 7.2 Determination 7.2.1 Dissolution of the test portion 7.2.1.1 Unalloyed and low alloyed steels and irons Transfer the test portion (7.1) into a 500 ml conical flask and dissolve it with 30 ml of nitric acid solution (4.3). 7.2.1.2 Alloyed stee
34、ls Transfer the test portion (7.1) into a 500 ml conical flask and start the dissolution by adding 20 ml of hydrochloric acid solution (4.4). NOTE Larger volumes of hydrochloric acid solution (4.4) can be necessary. Oxidise with 10 ml of nitric acid solution (4.3) or with 15 ml of aqua regia (4.5).
35、7.2.2 Preparation of the test solution Heat the test solution (7.2.1) until boiling, in order to expel nitrogen oxides. Cool and add water until about 80 ml. Whilst stirring slowly add, 80 ml of the sodium hydrogen carbonate solution (4.6). NOTE 1 The addition of the sodium hydrogen carbonate soluti
36、on (4.6) will partially neutralise the acids added for the sample dissolution. This will minimise the zinc amount that can be dissolved during the hydroxides precipitation with zinc oxide. BS EN 10071:2012EN 10071:2012 (E) 7 NOTE 2 Before the zinc oxide addition, the solution needs to be perfectly l
37、impid. The precipitate that can appear during the addition of the sodium hydrogen carbonate solution (4.6) will lead to a manganese loss. Consequently, if the test solution is not perfectly limpid, the precipitate needs to be dissolved by adding a minimum amount of nitric acid solution (4.3) and the
38、n boiling until the nitrogen oxides have been expelled. In all cases, boil the solution once again and add about 5 g of zinc oxide (4.2), whilst stirring vigorously. Transfer the solution and the precipitate into a 250 ml volumetric flask, cool, dilute to the mark with water (4.1) and mix. Filter th
39、e solution through a dry, fluted filter paper and collect the filtrate in an appropriate dry vessel, after having rejected the first fractions of the filtrate (a few millilitres). 7.2.3 Titration Transfer 350 ml of the sodium pyrophosphate solution (4.7) into a 600 ml beaker. According to the expect
40、ed manganese content of the sample, add the aliquot portion of the filtrate (7.2.2) specified in Table 1, whilst continuously and vigorously stirring by means of a magnetic stirrer (5.1), in order to avoid the precipitation of zinc phosphate. Table 1 Aliquot portion of the filtrate Expected manganes
41、e content of sample % Aliquot portion of the filtrate (7.2.2) ml Dilution ratio (D) 0,5 Mn 4 100,0 2,54 Mn 8 50,0 5,0 8 Mn 20,0 12,5 Adjust the pH to approximately 6,5 by adding nitric acid solution (4.3). This setting up is controlled either by means of a pH-meter (5.2) or by means of a pH indicato
42、r paper (4.10). Titrate with the potassium permanganate standard solution (4.9). Follow the progress of the titration by an electrometric measurement as for example, by means of a potentiometer (5.3). Let 2V be the volume, expressed in millilitres, of the potassium permanganate standard solution (4.
43、9) used for the titration. NOTE In presence of an excess of pyrophosphate, the pH of the test solution after the addition of the aliquot portion of the filtrate (7.2.2) is greater than 6,5. The adjustment of the pH value is therefore carried out by addition of an acid solution: this will avoid the f
44、ormation of precipitates difficult to redissolve, which can happen when the pH value has to be increased by addition of an alkaline solution. 8 Expression of results The manganese mass fraction (wMn), in percent (%), is given by the Formula (2): wMnm x 10D x C x 12V= (2) where BS EN 10071:2012EN 100
45、71:2012 (E) 8 2V is the volume in millilitres, of the potassium permanganate standard solution (4.9) used for the titration; 1C is the manganese concentration of the potassium permanganate standard solution (4.9), expressed in mg/ml; D is the dilution ratio (see Table 1); m is the mass, in grams, of
46、 the test portion (7.1). 9 Test report The test report shall contain the following information: a) identification of the test sample; b) method used; c) results; d) any unusual characteristics noted during the determination; e) any operation not included in this European Standard or in the document
47、to which reference is made or regarded as optional; f) date of the test and/or date of preparation or signature of the test report; g) signature of the responsible person. This page deliberately left blankBSI is the independent national body responsible for preparing British Standards and other stan
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