1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 13971:2012Carbonate and silicate limingmaterials Determination ofreactivity Potentiometrictitration method withhydrochloric acidBS EN 13971:2012 BRITISH STANDARDNational fo
2、rewordThis British Standard is the UK implementation of EN 13971:2012. Itsupersedes BS EN 13971:2008 which is withdrawn.BSI, as a member of CEN, is obliged to publish EN 13971:2012 as aBritish Standard. However, attention is drawn to the fact that duringthe development of this European Standard, the
3、 UK committee votedagainst its approval as a European Standard.The UK committee submitted a negative vote with respect to thisstandard due to concerns over reproducibility limits as described inTable 1. In two cases out of eight the reproducibility limit was 60 % andin all but three cases it exceede
4、d 30 %. The UK committee advises thatusers validate their performance.The UK participation in its preparation was entrusted to TechnicalCommittee CII/37, Fertilisers and related chemicals.A list of organizations represented on this committee can beobtained on request to its secretary.This publicatio
5、n does not purport to include all the necessaryprovisions of a contract. Users are responsible for its correctapplication. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 72251 6ICS 65.080; 91.100.10Compliance with a British Standard cannot confer immunit
6、y fromlegal obligations.This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 January 2013.Amendments issued since publicationDate Text affectedBS EN 13971:2012 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of EN
7、 13971:2012. Itsupersedes BS EN 13971:2008 which is withdrawn.BSI, as a member of CEN, is obliged to publish EN 13971:2012 as aBritish Standard. However, attention is drawn to the fact that duringthe development of this European Standard, the UK committee votedagainst its approval as a European Stan
8、dard.The UK committee submitted a negative vote with respect to thisstandard due to concerns over reproducibility limits as described inTable 1. In two cases out of eight the reproducibility limit was 60 % andin all but three cases it exceeded 30 %. The UK committee advises thatusers validate their
9、performance.The UK participation in its preparation was entrusted to TechnicalCommittee CII/37, Fertilisers and related chemicals.A list of organizations represented on this committee can beobtained on request to its secretary.This publication does not purport to include all the necessaryprovisions
10、of a contract. Users are responsible for its correctapplication. The British Standards Institution 2013. Published by BSI StandardsLimited 2013ISBN 978 0 580 72251 6ICS 65.080; 91.100.10Compliance with a British Standard cannot confer immunity fromlegal obligations.This British Standard was publishe
11、d under the authority of theStandards Policy and Strategy Committee on 31 January 2013.Amendments issued since publicationDate Text affectedBritish Standard. However, attention is drawn to the fact that during the development of this European Standard, the UK committee voted against its approval as
12、a European Standard.standard due to concerns over reproducibility limits as described in Table 1. In two cases out of eight the reproducibility limit was 60 % and in all but three cases it exceeded 30 %. The UK committee advises that users validate their performance.Amendments/corrigenda issued sinc
13、e publicationBS EN 13971:2012EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13971 December 2012 ICS 65.080 Supersedes EN 13971:2008English Version Carbonate and silicate liming materials - Determination of reactivity - Potentiometric titration method with hydrochloric acidAmendements minraux b
14、asiques carbonats et silicats -Dtermination de la ractivit - Mthode par titrage potentiomtrique lacide chlorhydrique Carbonatische und silikatische Kalke - Bestimmung der Reaktivitt - Potentiometrisches Titrationsverfahren mit Salzsure This European Standard was approved by CEN on 3 November 2012. C
15、EN 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 bibliographical references concerning such national standards may be obtained on ap
16、plication 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 language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
17、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, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, L
18、atvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, 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-
19、1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13971:2012: EBS EN 13971:2012EN 13971:2012 (E) 2 Contents Page Foreword 3Introduction .41 Scope 52 Normative references 53 Principle 54 Apparatus .55 Reagents .66 P
20、reparation of the test sample .67 Procedure .78 Expression of results 99 Precision 1010 Test report . 12Annex A (normative) Preparation of the test portion of liming materials coarser than 1 mm . 13Annex B (normative) Arrangement of the test apparatus 14Bibliography . 16BS EN 13971:2012EN 13971:2012
21、 (E) 3 Foreword This document (EN 13971:2012) has been prepared 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 end
22、orsement, at the latest by June 2013, and conflicting national standards shall be withdrawn at the latest 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 identifyi
23、ng any or all such patent rights. This document supersedes EN 13971:2008. The following has been added to 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 fo
24、rmula for silicates added; d) subclauses 7.1.2 and 7.2.2 enlarged concerning determination of silicate liming 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
25、 materials added; g) Bibliography revised. 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
26、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 and the United Kingdom. BS EN 13971:2012EN 13971:2012 (E) 4 Introduc
27、tion The results obtained by this method can be used to estimate the behaviour of the liming material 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 valu
28、e, but to classify the different product groups. BS EN 13971:2012EN 13971:2012 (E) 5 1 Scope This 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 l
29、iming materials by potentiometric titration with hydrochloric acid. This method is applicable only 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 No
30、rmative references The following documents, in whole or in part, are 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 amendment
31、s) applies. EN 1482-2, Fertilizers and liming materials Sampling and sample preparation Part 2: 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 Determin
32、ation of neutralizing value Titrimetric methods EN 12947, Liming materials Determination of magnesium 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 Oxalat
33、e method 3 Principle Decomposition of carbonates and silicates with acids according to the following 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 giv
34、en time is a direct measure of the reaction rate of the liming materials being tested. 4 Apparatus Usual laboratory apparatus and, in particular, the following: 4.1 pH meter, with electrode. BS EN 13971:2012EN 13971:2012 (E) 6 4.2 Burette. NOTE Used only for 5,0 mol/l hydrochloric acid solution (5.2
35、). 4.2.1 50 ml motor driven burette (for automatic titration),a pH stat function is recommended, 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
36、beaker. 4.5 Magnetic stirrer rod, (9 1) mm diameter times (50 1) mm length, with central ring. 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 s
37、olution, mass fraction, w(HCl) = 25 %. 5.2 Hydrochloric acid, standard volumetric solution, 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 c
38、hemical characteristics. However, physical characteristics are not granted. The use of a highly 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
39、Standard buffer solution, pH = 2,0 (commercial solution). NOTE This has a limited life. 5.6 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
40、 716 DMS Titrino is an example of a suitable product available commercially. This information 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 result
41、s. 2) This substance is an example of a suitable product available commercially. This information is given for the convenience of users of this document and does not constitute an endorsement by CEN of this product.BS EN 13971:2012EN 13971:2012 (E) 7 6.2 Dry the test sample in accordance with EN 120
42、48. Record the result for information only. 6.3 Use the dried test sample without further 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 Pro
43、cedure 7.1 Automatic titration 7.1.1 Calibration 7.1.1.1 Calibrate the pH meter (4.1) 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
44、 re-calibrate with the standard buffer solutions. Checking and cleaning is more frequently 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 positi
45、on “continuous working” and a standard flow rate of 35 ml/min to 38 ml/min. NOTE Wide 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 apparat
46、us shall be arranged according to Figure B.1. 7.1.1.4 Set the magnetic stirrer speed 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. Fo
47、r apparatus with a step length adjustment, set the adjustment at the middle position. 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
48、before reaching the electrode (4.1). Avoid contact with the walls of the glass beaker. 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 b
49、e stirred for 30 s. Start the stop-watch (4.6) and commence the titration, adding the 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 the acid consumption is (20,0 0,2) ml of 5,0 mol/l hydrochloric acid (5.2). During the proc
