1、January 2017 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 65.080!%_)“2605906www.din.deDIN
2、EN 12945Liming materials Determination of neutralizing value Titrimetric methods;English version EN 12945:2014+A1:2016,English translation of DIN EN 12945:2017-01Kalkdnger Bestimmung des Neutralisationswertes Titrimetrische Verfahren;Englische Fassung EN 12945:2014+A1:2016,Englische bersetzung von D
3、IN EN 12945:2017-01Amendements minraux basiques Dtermination de la valeur neutralisante Mthodes par titrimtrie;Version anglaise EN 12945:2014+A1:2016,Traduction anglaise de DIN EN 12945:2017-01SupersedesDIN EN 12945:201407www.beuth.deDTranslation by DIN-Sprachendienst.In case of doubt, the German-la
4、nguage original shall be considered authoritative.Document comprises 16 pages 01.17 DIN EN 12945:2017-01 2 A comma is used as the decimal marker. National foreword This document (EN 12945:2014+A1:2016) has been prepared by Technical Committee CEN/TC 260 “Fertilizers and liming materials” (Secretaria
5、t: DIN, Germany) with the active participation of German experts. The responsible German body involved in its preparation was DIN-Normenausschuss Lebensmittel und landwirtschaftliche Produkte (DIN Standards Committee Food and Agricultural Products), Working Committee NA 057-03-02 AA Dngemittel. The
6、DIN Standards corresponding to the International Standards referred to in this document is as follows: ISO 3310-1 DIN ISO 3310-1 ISO 5725 DIN ISO 5725 Amendments This standard differs from DIN EN 12945:2014-07 as follows: a) Clause 9 has been amended so that the neutralizing value may be expressed a
7、s CaOequivalent or alternatively as HOequivalent; b) Annex B with corresponding conversion factors between CaOand HO has been added; c) the Bibliography has been revised; d) the standard has been editorially revised. Previous editions DIN EN 12945: 2003-01, 2008-05, 2009-09, 2014-07 National Annex N
8、A (informative) Bibliography DIN ISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth DIN ISO 5725 (all parts), Accuracy (trueness and precision) of measurement methods and results EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 12945:2014+A1 Octobe
9、r 2016 ICS 65.080 Supersedes EN 12945:2014English Version Liming materials - Determination of neutralizing value - Titrimetric methods Amendements minraux basiques - Dtermination de la valeur neutralisante - Mthode par trimtrie Kalkdnger - Bestimmung des Neutralisationswertes - Titrimetrische Verfah
10、ren This European Standard was approved by CEN on 8 February 2014 and includes Amendment 1 approved by CEN on 11 June 2016. 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 wit
11、hout 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 exists in three official versions (English, French, German). A version in any other
12、 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 standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, D
13、enmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey andUnited Kingdom. EUROPEAN COMMITT
14、EE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels 2016 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12945:2014+A1:2016 EtisEN 12
15、945:2014+A1:2016 (E) 2 Contents Page European foreword . 3 Introduction 4 1 Scope 5 2 Normative references 5 3 Terms and definitions . 5 4 Principle . 5 5 Reagents . 5 6 Apparatus . 6 7 Sampling . 6 8 Procedure. 6 9 Calculation and expression of results for method A and method B 8 10 Precision . 9 1
16、1 Test report . 9 Annex A (informative) Results of an inter-laboratory trial to determine the neutralizing value 10 Annex B (informative) !Conversion tables“ . 11 Bibliography . 14 DIN EN 12945:2017-01 EN 12945:2014+A1:2016 (E) 3 European foreword This document (EN 12945:2014+A1:2016) has been prepa
17、red by Technical Committee CEN/TC 260 “Fertilizers 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 April 2017 and conflicting nation
18、al standards shall be withdrawn at the latest by April 2017. 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 includes Am
19、endment 1 approved by CEN on 11 June 2016. This document supersedes !EN 12945:2014“. The start and finish of text introduced or altered by amendment is indicated in the text by tags !“. The following changes !had been made to the former edition EN 12945:2008“: a) scope modified taking into account t
20、hat method A is not applicable to liming materials with more than 3 % P2O5and that method B is applicable to all liming materials; b) reference to EN 14984 added to the scope and the Bibliography; c) 9.2 amended by addition of an instruction concerning the use of correction factors; d) optional requ
21、irement concerning correction factors added to Clause 11 Test report; e) corrigendum EN 12945:2008/AC:2009 included; f) editorially revised. !The following changes were made to the previous edition EN 12945:2014: g) Clause 9 modified taking into account that the neutralizing value may be expressed a
22、s CaO-equivalents or alternatively as HO-equivalents; h) Annex B with conversion factors between CaO and HO- added; i) Bibliography revised; j) document editorially revised.“ According to the CEN-CENELEC Internal Regulations, the national standards organisations of the following countries are bound
23、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, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,
24、Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. DIN EN 12945:2017-01 EN 12945:2014+A1:2016 (E) 4 Introduction Two different procedures are described (method A and method B) because the titration to pH 7,0 is not applicable to silicate liming materials due to t
25、he precipitation of compounds at this pH value. In method B the turning point at pH 4,8 on the titration curve is taken as the end-point of the titration. For carbonaceous liming materials the difference in the consumption of sodium hydroxide solution for back titration between the titration end-poi
26、nts of pH 4,8 and pH 7,0 is negligible. DIN EN 12945:2017-01 EN 12945:2014+A1:2016 (E) 5 1 Scope This European Standard specifies two methods for the determination of the neutralizing value (NV) of liming materials. Method A is applicable to all liming materials except silicate liming materials. Met
27、hod B is applicable to all liming materials. Both methods do not correctly take into account the potential neutralizing value of material containing more than 3 % P2O5. For a more accurate agronomic assessment of products containing more than 3 % P2O5determine the liming efficiency according to EN 1
28、4984. NOTE The methods described in ISO 6598 1 and ISO 7497 2 can be used for the determination of P2O5content. Further information on P analyses is given in 3 and 4. 2 Normative references The following documents, in whole or in part, are normatively referenced in this document and are indispensabl
29、e 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: Sample preparation EN 12944-3:200
30、1, Fertilizers and liming materials Vocabulary Part 3: Terms relating to liming materials EN ISO 3696, Water for analytical laboratory use Specification and test methods (ISO 3696) ISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire cloth 3 Terms and definiti
31、ons For the purposes of this document, the terms and definitions given in EN 12944-3:2001 apply. 4 Principle Dissolution of the sample in a specified quantity of hydrochloric acid standard solution. Determination of the excess acid by back titration with a sodium hydroxide standard solution. 5 Reage
32、nts During the analysis, unless otherwise stated, use only reagents of recognised analytical grade. NOTE Commercially available solutions can be used. 5.1 Water, according to EN ISO 3696, grade 3. 5.2 Hydrochloric acid standard solution, c(HCl) = 0,5 mol/l. Determine the exact concentration of the s
33、olution by titration with sodium hydroxide standard solution (5.3) using phenolphthalein solution (5.4) as indicator. Apply the appropriate correction factor in the calculation of the results (see Clause 9). DIN EN 12945:2017-01 EN 12945:2014+A1:2016 (E) 6 5.3 Sodium hydroxide standard solution, c(N
34、aOH) = 0,25 mol/l. Determine the exact concentration of the standard solution by titration against approximately 2 g of dried potassium hydrogen phthalate (KHC8H4O4), weighed to the nearest 0,001 g. The solution shall be stored in a polyethylene bottle and absorption of carbon dioxide during storage
35、 should be avoided. NOTE 1 ml of 0,25 mol/l sodium hydroxide solution is equivalent to 51,055 mg of potassium hydrogen phthalate. Apply the appropriate correction factor in the calculation of the results (see Clause 9). 5.4 Phenolphthalein indicator solution. Dissolve 0,25 g of phenolphthalein in 15
36、0 ml of ethanol with a mass fraction of 93 % and dilute with water to 250 ml. Use the phenolphthalein solution (5.4) as an indicator. 5.5 Hydrogen peroxide solution. Dilute one volume of hydrogen peroxide (H2O2) = 30 g/100 ml with four volumes of water. 6 Apparatus Usual laboratory apparatus and, in
37、 particular, the following: 6.1 Test sieve, conforming to the requirements of ISO 3310-1, of nominal aperture size 250 m. 6.2 pH meter, minimum sensitivity 0,05 pH units, with a suitable glass electrode and a calomel or other reference electrode or a combined electrode, calibrated using two buffer s
38、olutions whose pH values cover the range pH 4 to pH 7. 6.3 Mechanical stirrer, e.g. magnetic stirrer. 6.4 Desiccator. 7 Sampling Sampling is not part of the method specified in this European Standard. !Recommended sampling methods are described in EN 1482-1 5 and EN 1482-3 6.“ Prepare the sample of
39、the liming materials in accordance with EN 1482-2. 8 Procedure 8.1 Preparation of the test sample Dry the test sample at (105 2) C to constant mass. Record the as-received (mw) and dry (md) masses. Grind the sample so that it passes the 250 m test sieve (6.1). Mix thoroughly and store the sample in
40、a desiccator (6.4). DIN EN 12945:2017-01 EN 12945:2014+A1:2016 (E) 7 8.2 Determination 8.2.1 Method A 8.2.1.1 Test portion Weigh about 0,5 g, to the nearest 0,001 g, of burnt or hydrated lime or 1 g of ground limestone or ground marl (prepared according to 8.1) into a 250 ml conical flask. 8.2.1.2 T
41、itration Add 50 ml of the hydrochloric acid standard solution (5.2) with continuous shaking and boil gently for 10 min, using boiling granules. Cool to ambient temperature. Transfer quantitatively into a 250 ml beaker and insert the electrodes of the pH meter (6.2) and a stirrer (6.3). Titrate with
42、the sodium hydroxide standard solution (5.3) with moderate stirring (avoid splashing) until a pH of 7,0 is stable for 1 min whilst stirring is maintained. 8.2.2 Method B 8.2.2.1 Test portion Weigh about 0,5 g, to the nearest 0,001 g, of the prepared test sample (8.1) into a 250 ml conical flask. 8.2
43、.2.2 Titration Rinse the inside walls of the flask with 10 ml of water. Add 35 ml of the hydrochloric acid standard solution (5.2) with continuous shaking. Heat and boil gently for 10 min to dissolve the sample using boiling granules. Stir continuously. Cool to ambient temperature, then dilute with
44、water to about 100 ml and add 5 ml of hydrogen peroxide solution (5.5). NOTE Ferrous ions in silicate liming materials are oxidized by hydrogen peroxide to ferric ions before titration, because ferrous ions otherwise would consume hydrogen ions during titration. Transfer quantitatively into a 200 ml
45、 graduated flask; make up the volume with water and mix. Pass through a dry filter into a dry container, discarding the initial portion. Pipette an aliquot portion of 100 ml of the solution into a 250 ml beaker. Insert the electrodes of the pH meter (6.2) and a stirrer (6.3). Titrate with the sodium
46、 hydroxide standard solution (5.3) with moderate stirring (avoid splashing) until a pH of 4,8 is stable for 1 min (whilst stirring is maintained). DIN EN 12945:2017-01 EN 12945:2014+A1:2016 (E) 8 9 Calculation and expression of results for method A and method B 9.1 Calculate the neutralizing value o
47、f the dried product, Nd, according to Formula (1): ! ( ) =111 222dt100c V f A V fNmA(1) where c is the factor to convert hydrochloric acid standard solution consumption into CaO or HO-equivalent; c = 0,028 when neutralizing value should be expressed as CaO c = 0,017 when neutralizing value should be
48、 expressed as HO-1is the molarity of hydrochloric acid standard solution (5.2), in mol/l; V1is the total volume of hydrochloric acid standard solution (5.2), in millilitres; f1is the factor of hydrochloric acid standard solution (5.2); A is equal to 1 for method A, and the factor of the taken aliquo
49、t is 0,5 for method B; 2is the molarity of sodium hydroxide standard solution (5.3), in mol/l; V2is the volume of sodium hydroxide standard solution (5.3), in millilitres; f2is the factor of sodium hydroxide standard solution (5.3); mtis the mass of the test portion in the aliquot portion taken, in grams.“ 9.2 Calculate the neutralizing value of the “as-received” product, Nar, according to Formula (2) =ddarwNmNm(2) where
