1、March 2013 Translation by DIN-Sprachendienst.English price group 11No part of this translation may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS
2、65.080!$ou“1957682www.din.deDDIN EN 13971Carbonate and silicate liming materials Determination of reactivity Potentiometric titration method with hydrochloric acid;English version EN 13971:2012,English translation of DIN EN 13971:2013-03Carbonatische und silikatische Kalke Bestimmung der Reaktivitt
3、Potentiometrisches Titrationsverfahren mit Salzsure;Englische Fassung EN 13971:2012,Englische bersetzung von DIN EN 13971:2013-03Amendements minraux basiques carbonats et silicats Dtermination de la ractivit Mthode par titrage potentiomtrique lacide chlorhydrique;Version anglaise EN 13971:2012,Tradu
4、ction anglaise de DIN EN 13971:2013-03SupersedesDIN EN 13971:2008-05www.beuth.deDocument comprises 18 pagesIn case of doubt, the German-language original shall be considered authoritative.02.13DIN EN 13971:2013-03 2 A comma is used as the decimal marker. National foreword This document (EN 13971:201
5、2) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials” (Secretariat: DIN, Germany). The responsible German body involved in its preparation was the Normenausschuss Lebensmittel und landwirtschaftliche Produkte (Food and Agricultural Products Standards Committee), W
6、orking Committee NA 057-03-02 AA Dngemittel. The DIN Standard corresponding to the International Standard referred to in this document is as follows: ISO 5725 DIN ISO 5725 Amendments This standard differs from DIN 13971:2008-05 as follows: a) silicate liming materials have been included in the title
7、 and in the scope; b) EN 12947 and EN 13475 have been added to the normative references; c) a reaction formula for silicates has been included in Clause 3; d) the determination of silicate liming materials has been added to Subclauses 7.1.2 and 7.2.2; e) Subclause 8.2 and Formulas (2), (3) and (4) h
8、ave been added for the expression of results for silicate liming materials; f) Subclause 9.2 and Table 2 have been added to the precision data for silicate liming materials; g) the Bibliography has been revised. Previous editions DIN EN 13971: 2003-04, 2008-05 National Annex NA (informative) Bibliog
9、raphy DIN ISO 5725, Precision of test methods Determination of repeatability and reproducibility for a standard test method by inter-laboratory tests (identical with ISO 5725:1086 (now withdrawn) was used to obtain the precision data. EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13971 Decemb
10、er 2012 ICS 65.080 Supersedes EN 13971:2008English Version Carbonate and silicate liming materials - Determination of reactivity - Potentiometric titration method with hydrochloric acidAmendements minraux basiques carbonats et silicats -Dtermination de la ractivit - Mthode par titrage potentiomtriqu
11、e lacide chlorhydrique Carbonatische und silikatische Kalke - Bestimmung der Reaktivitt - Potentiometrisches Titrationsverfahren mit Salzsure This European Standard was approved by CEN on 3 November 2012. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the c
12、onditions 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 member. This European Standard ex
13、ists 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. CEN members are the national s
14、tandards 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, Portugal, Romania, Slovakia,
15、 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 by any means reserved worldw
16、ide for CEN national Members. Ref. No. EN 13971:2012: EEN 13971:2012 (E) 2 Contents Page Foreword 3Introduction .41 Scope 52 Normative references 53 Principle 54 Apparatus .55 Reagents .66 Preparation of the test sample .67 Procedure .78 Expression of results 99 Precision 1010 Test report . 12Annex
17、A (normative) Preparation of the test portion of liming materials coarser than 1 mm . 13Annex B (normative) Arrangement of the test apparatus 14Bibliography . 16DIN EN 13971:2013-03 EN 13971:2012 (E) 3 Foreword This document (EN 13971:2012) has been prepared by Technical Committee CEN/TC 260 “Fertil
18、izers and liming materials”, the secretariat of which is held by DIN. This European Standard shall be given the status of a national standard, either by publication of an identical text or by endorsement, at the latest by June 2013, and conflicting national standards shall be withdrawn at the latest
19、 by June 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 responsible for identifying any or all such patent rights. This document supersedes EN 13971:2008. The following has been added to
20、 the former edition of the European Standard: a) silicate liming materials added to the scope and to the title; b) EN 12947 and EN 13475 added to the normative references; c) Clause 3 reaction formula for silicates added; d) subclauses 7.1.2 and 7.2.2 enlarged concerning determination of silicate li
21、ming materials; e) subclause 8.2 and formulas (2), (3) and (4) on expression of results for silicate liming materials added; f) subclause 9.2 and Table 2 on the precision data for silicate liming materials added; g) Bibliography revised. According to the CEN/CENELEC Internal Regulations, the nationa
22、l 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, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithua
23、nia, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. DIN EN 13971:2013-03 EN 13971:2012 (E) 4 Introduction The results obtained by this method can be used to estimate the behaviour of the liming materia
24、l in the soil. The results show a good correlation with the results obtained by a soil incubation method (see 1 to 5). Regarding the precision of the method, the results are not used to declare a value, but to classify the different product groups. DIN EN 13971:2013-03 EN 13971:2012 (E) 5 1 Scope Th
25、is European Standard specifies a method for the determination of the speed and effectiveness of the neutralising potential of calcium carbonate, calcium magnesium carbonate and calcium magnesium silicate liming materials by potentiometric titration with hydrochloric acid. This method is applicable o
26、nly to liming materials with a maximum particle size of 6,3 mm. The type of liming material should be identified according to EN 14069 and the particle size should be determined according to EN 12948. 2 Normative references The following documents, in whole or in part, are normatively referenced in
27、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 1482-2, Fertilizers and liming materials Sampling and sample preparation Part 2:
28、 Sample preparation EN 12048, Solid fertilizers and liming materials Determination of moisture content Gravimetric method by drying at (105 2) C (ISO 8190:1992 modified) EN 12945, Liming materials Determination of neutralizing value Titrimetric methods EN 12947, Liming materials Determination of mag
29、nesium content Atomic absorption spectrometric method EN 12948, Liming materials Determination of size distribution by dry and wet sieving EN 13475, Liming materials Determination of calcium content Oxalate method 3 Principle Decomposition of carbonates and silicates with acids according to the foll
30、owing reactions: MeCO3+ 2 H+ Me2+ H2O + CO2 MeSiO4+ 2 H+ Me(OH)2+ SiO2Titration under stable pH conditions either with an automatic titration apparatus or a manual method. The acid consumption during a given time is a direct measure of the reaction rate of the liming materials being tested. 4 Appara
31、tus Usual laboratory apparatus and, in particular, the following: 4.1 pH meter, with electrode. DIN EN 13971:2013-03 EN 13971:2012 (E) 6 4.2 Burette. NOTE Used only for 5,0 mol/l hydrochloric acid solution (5.2). 4.2.1 50 ml motor driven burette (for automatic titration),a pH stat function is recomm
32、ended, for example Metrohm 716 DMS Titrino1). 4.2.2 50 ml burette (for manual titration). 4.3 250 ml glass beaker, with an inner diameter of 65 mm. 4.4 Magnetic stirrer, with centring mark for the 250 ml glass beaker. 4.5 Magnetic stirrer rod, (9 1) mm diameter times (50 1) mm length, with central r
33、ing. 4.6 Stop-watch. 4.7 Filter paper, acid-proof, medium filtration speed, average retention capacity about 5 m to 12 m. 5 Reagents All reagents shall be of recognised analytical grade. 5.1 Hydrochloric acid solution, mass fraction, w(HCl) = 25 %. 5.2 Hydrochloric acid, standard volumetric solution
34、, c(HCl) = 5,0 mol/l. 5.3 Calcium carbonate, precipitated, mass fraction, w(CaCO3) = of at least 99 %. Precipitated calcium carbonate is from crystalline origin. Commercial PCC for analysis is granted for its chemical characteristics. However, physical characteristics are not granted. The use of a h
35、ighly reactive PCC, such as commercial PCC from VWR / Prolabo / BDH, reference GPR, Rectapur, Ref 22296.294, Molar mass 100,092)which will consume 15 ml after 15 min, is recommended. 5.4 Silicone defoamer. 5.5 Standard buffer solution, pH = 2,0 (commercial solution). NOTE This has a limited life. 5.
36、6 Standard buffer solution, pH = 4,0, (commercial solution). NOTE This has a limited life. 6 Preparation of the test sample 6.1 Prepare the sample of the liming material in accordance with EN 1482-2. 1) Metrohm 716 DMS Titrino is an example of a suitable product available commercially. This informat
37、ion is given for the convenience of users of this European Standard and does not constitute an endorsement by CEN of this product. Equivalent products may be used if they can be shown to lead to the same results. 2) This substance is an example of a suitable product available commercially. This info
38、rmation is given for the convenience of users of this document and does not constitute an endorsement by CEN of this product.DIN EN 13971:2013-03 EN 13971:2012 (E) 7 6.2 Dry the test sample in accordance with EN 12048. Record the result for information only. 6.3 Use the dried test sample without fur
39、ther preparation, e.g. grinding. 6.4 Weigh a 5,0 g test portion of the dried sample to the nearest 0,01 g. For liming materials coarser than 1 mm, the test portion shall be prepared in accordance with Annex A. 7 Procedure 7.1 Automatic titration 7.1.1 Calibration 7.1.1.1 Calibrate the pH meter (4.1)
40、 with two standard buffer solutions, pH 2,0 (5.5) and pH 4,0 (5.6). The pH electrode shall react quickly. Check the sluggishness of the electrode and if necessary, clean it carefully with hydrochloric acid (5.1) and re-calibrate with the standard buffer solutions. Checking and cleaning is more frequ
41、ently required for liming materials containing clay. It is recommended to flush the acid introduction pipe between each sample for slow reacting samples. 7.1.1.2 Adjust the motor driven burette (4.2.1) to the position “continuous working” and a standard flow rate of 35 ml/min to 38 ml/min. NOTE Wide
42、 deviations in the flow rate adversely affect the results obtained. 7.1.1.3 Place the glass beaker (4.3) centrally on the magnetic stirrer (4.4). Add 100 ml water and the magnetic stirrer rod (4.5). The test apparatus shall be arranged according to Figure B.1. 7.1.1.4 Set the magnetic stirrer speed
43、control to between 500 min-1and 600 min-1. Fill the burette (4.2.1) with 5,0 mol/l hydrochloric acid (5.2). 7.1.1.5 Adjust the titration control so that the stepwise run of the titration only starts below pH 2,5. For apparatus with a step length adjustment, set the adjustment at the middle position.
44、 7.1.1.6 Set up the electrode (4.1) and the burette (4.2.1) in the glass beaker (4.3) according to Figure B.1. This is to ensure that the added hydrochloric acid (5.2) is mixed with the contents of the glass beaker before reaching the electrode (4.1). Avoid contact with the walls of the glass beaker
45、. 7.1.1.7 For the exact adjustment of the operating conditions, start the magnetic stirrer (4.4) and add (5,00 0,01) g of calcium carbonate (5.3) to the stirred water in the glass beaker (4.3). The solution should be stirred for 30 s. Start the stop-watch (4.6) and commence the titration, adding the
46、 hydrochloric acid (5.2) in a fast sequence of drops, aiming at a pH value of 2,0. When pH 2,5 is reached, add the hydrochloric acid more slowly. Use (16 0,2) ml of hydrochloric acid in the first 30 s and then continue with stepwise additions to dissolve the remaining carbonate within 60 s. Check th
47、e acid consumption is (20,0 0,2) ml of 5,0 mol/l hydrochloric acid (5.2). During the procedure the solution shall not be allowed to fall below pH 2,0 by more than 0,2 pH units, even for a short time. If the material being tested foams very strongly, one drop of silicon defoamer (5.4) should be added
48、 to the solution. When operating conditions are correctly adjusted, about 80 % of the mass of calcium carbonate is dissolved by the first 16 ml of hydrochloric acid (5.2) which should run almost uninterrupted. The remaining amount of calcium carbonate should be dissolved by a further 4 ml of hydroch
49、loric acid, added stepwise, within the next DIN EN 13971:2013-03 EN 13971:2012 (E) 8 60 s. Any fine adjustment that might be necessary can be carried out by a slight alteration to the start of the stepwise titration or by changing the length of the titration. A pH stat function is recommended for the titration. 7.1.2 Determination 7.1.2.1 Set up the apparatus as described in 7.1.1.1 to 7.1.1.6. 7.1.2.2 Add the weighed test portion (6.4) to the stirr
