SIST EN 16357:2013
(Main)Carbonate liming materials - Determination of reactivity - Automatic titration method with citric acid
Carbonate liming materials - Determination of reactivity - Automatic titration method with citric acid
This European Standard specifies a method for the determination of the reactivity of calcium carbonate and calcium magnesium carbonate liming materials. It assesses the speed and effectiveness of their neutralising potential by automatic titration with citric acid. This method is applicable only to liming materials with a maximum particle size of 6,3 mm determined according to EN 12948.
Carbonatische Kalke - Bestimmung der Reaktivität - Automatisches Titrationsverfahren mit Citronensäure
Dieses Dokument legt ein Verfahren für die Bestimmung der Reaktivität von Calciumcarbonat sowie carbonatischen Calcium-/Magnesium-Bodenverbesserungsmitteln fest. Die Geschwindigkeit und Wirksamkeit deren Neutralisationspotentials werden durch automatische Titration mit Citronensäure beurteilt.
Dieses Verfahren ist nur für Calcium-/Magnesium-Bodenverbesserungsmittel mit einer Korngröße von höchstens 6,3 mm anwendbar. Die Korngröße ist nach EN 12948 zu bestimmen.
Amendements minéraux basiques carbonatés - Détermination de la réactivité - Méthode par titration automatique à l'acide citrique
La présente norme européenne spécifie une méthode de détermination de la réactivité des amendements minéraux basiques à base de carbonate de calcium ou à base de carbonate de calcium et de magnésium. Il évalue la rapidité et l'efficacité de leur potentiel de neutralisation par titration automatique à l'acide citrique.
Cette méthode s'applique uniquement aux amendements minéraux basiques ayant une taille de particules maximale de 6,3 mm déterminée selon l'EN 12948.
NOTE Pour les dolomies d’origine métamorphique (de type marbre) (Procédure BET selon l’ISO 9277 en-dessous de 500 m²/kg), voir EN 14984.
Karbonatna sredstva za apnjenje - Določevanje reaktivnosti - Metoda avtomatske titracije s citronsko kislino
Ta evropski standard določa metodo za določevanje reaktivnosti sredstev za apnenje s kalcijevim karbonatom in kalcijevim magnezijevim karbonatom. Ugotavlja hitrost in učinkovitost njihovega nevtralizacijskega potenciala z avtomatsko titracijo s citronsko kislino. Ta metoda se uporablja samo za sredstva za apnenje z največjo velikostjo delcev 6,3 mm, ki je v skladu s standardom EN 12948.
General Information
Standards Content (Sample)
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Carbonatische Kalke - Bestimmung der Reaktivität - Automatisches Titrationsverfahren mit CitronensäureAmendements minéraux basiques carbonatés - Détermination de la réactivité - Méthode par titration automatique à l'acide citriqueCarbonate liming materials - Determination of reactivity - Automatic titration method with citric acid65.080GnojilaFertilizersICS:Ta slovenski standard je istoveten z:EN 16357:2013SIST EN 16357:2013en,fr,de01-oktober-2013SIST EN 16357:2013SLOVENSKI
STANDARD
SIST EN 16357:2013
EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM
EN 16357
August 2013 ICS 65.080 English Version
Carbonate liming materials - Determination of reactivity - Automatic titration method with citric acid
Amendements minéraux basiques carbonatés - Détermination de la réactivité - Méthode par titration automatique à l'acide citrique
Carbonatische Kalke - Bestimmung der Reaktivität - Automatisches Titrationsverfahren mit Citronensäure This European Standard was approved by CEN on 29 June 2013.
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 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 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, 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, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG
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Avenue Marnix 17,
B-1000 Brussels © 2013 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 16357:2013: ESIST EN 16357:2013
EN 16357:2013 (E) 2 Contents Page Foreword . 3 Introduction . 4 1 Scope . 5 2 Normative references . 5 3 Principle. 5 4 Apparatus . 5 5 Reagents . 6 6 Sampling and sample preparation . 7 6.1 General . 7 6.2 Preparation of the test sample . 8 6.3 Preparation of the test portion . 8 7 Procedure . 8 7.1 General . 8 7.2 Calibrations . 8 7.3 Measurement . 10 7.4 Determination of neutralising value . 11 7.5 Determination of MgO content . 11 8 Calculation and expression of the results . 11 9 Precision . 12 9.1 Inter-laboratory tests . 12 9.2 Repeatability . 12 9.3 Reproducibility . 12 10 Test report . 13 Annex A (normative)
Preparation of the test portion of liming materials coarser than 1 mm . 14 A.1 General . 14 A.2 Calculation of mass fractions retained on the test sieves . 14 A.3 Calculation of the test portion to be weighed . 14 Annex B (normative)
Arrangement of the test apparatus . 15 Bibliography. 16
SIST EN 16357:2013
EN 16357:2013 (E) 3 Foreword This document (EN 16357:2013) 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 endorsement, at the latest by February 2014, and conflicting national standards shall be withdrawn at the latest by February 2014. 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. According to the CEN-CENELEC Internal Regulations, the national standards organizations 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, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. SIST EN 16357:2013
EN 16357:2013 (E) 4 Introduction This method has been prepared to improve existing agricultural reactivity methods (see [1], [2], [3], [4] and [5]) for carbonate liming materials: duration, accuracy, representativeness, closer from soil conditions, automation. Attention is drawn to the following critical steps: — identification of the liming material type (influence on precision data); — size distribution (influence on test portion preparation and amount); — calibration of pH electrode (influence on titrator’s pH adjustments); — pH stat programme setting (influence on accuracy of added amounts of citric acid solution); — suitability of PCC used to check calibration; — stirring device (provides homogeneousness without grinding); — additional uncertainty with neutralising value and MgO content determination. SIST EN 16357:2013
EN 16357:2013 (E) 5 1 Scope This European Standard specifies a method for the determination of the reactivity of calcium carbonate and calcium magnesium carbonate liming materials. It assesses the speed and effectiveness of their neutralising potential by automatic titration with citric acid. This method is applicable only to liming materials with a maximum particle size of 6,3 mm determined according to EN 12948. NOTE For marble dolomite (BET procedure according to ISO 9277 below 500 m2/kg), see EN 14984. 2 Normative 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 amendments) 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, modified) EN 12945, Liming materials — Determination of neutralizing value — Titrimetric methods EN 12948, Liming materials — Determination of size distribution by dry and wet sieving EN ISO 3696, Water for analytical laboratory use — Specification and test methods (ISO 3696) 3 Principle Limited decomposition of carbonates in a given time with acid according to the following reaction: 2223COOHMeH2MeCO++→+++ Titration under stable pH conditions (pH 4,5) with an automatic titration apparatus. The citric acid consumption during a given time (15 min) is a direct measure for the reaction of the liming materials being tested. 4 Apparatus Usual laboratory apparatus and, in particular, the following: 4.1 pH meter with electrode. This instrument is generally included in the automatic motor driven burette device. 4.2 Automatic motor driven burette, capacity 20 ml. This kind of burette is generally equipped with all necessary accessories such as pH regulation programme (pH stat), automatic refilling device, pH electrode, continuous pH measurement and propeller stirring device. Though a propeller stirring device is preferred, a magnetic stirring device (4.7) may be used, provided the central ring of the stirrer rod is thick enough and does not lead to grind the tested material. Make sure the rotation speed of the stirrer rod is fast enough to make homogeneous dispersion in the beaker. If not, increase the speed up to the necessary value. SIST EN 16357:2013
EN 16357:2013 (E) 6 The burette shall be able to deliver at least 0,05 ml of citric acid solution (5.3) per second. This is to ensure the first part of the reaction (pH dropping from initial pH value to target pH value (4,5) will not be a limiting factor for liming material dissolution speed). This figure is higher than the flow rate obtained with the fastest reaction observed in preliminary tests. The burette shall be able to deliver its whole content in at least 4 000 steps to ensure accuracy for low amount of citric acid solution (5.3). NOTE This condition is always fulfilled with modern titrators. All contemporary (less than 10 years old) titrators allow such accuracy: i.e. minimum step amount: 0,002 5 ml for a 10 ml burette, or 0,012 5 ml for a 50 ml burette. This is sufficient, even for low amounts. However, this accuracy is obtained only if correct (minimal) step volume in titrator setup is specified. If not, the precision of the method will be altered. Use the burette only for the citric acid solution (5.3). For liming materials coarser than 1 mm, use a 50 ml burette. For most of products, a 10 ml burette is sufficient. However, a 20 ml burette is necessary for highly reactive chalks and precipitated calcium carbonate. Because refilling takes a significant time, this can bias the results. If volumes higher than 10 ml are expected, do not use the automatic refilling possibility and use a 20 ml or a 50 ml burette. 4.3 Glass beaker, capacity 100 ml. For liming materials coarser than 1 mm, use a 200 ml beaker. Minimum diameter in case of magnetic stirring device (4.7): 50 mm. 4.4 Stop-watch. 4.5 Balance, capable of weighing 10 g to the nearest 0,01 g. 4.6 Sample changer, optional. If occurring, a beaker of water (5.1) shall be inserted between two samples. 4.7 Magnetic stirring device, optional, see 4.2. Capable of minimum 500 min−1 speed rotation. Stirrer rod minimum length: 40 mm. 5 Reagents All reagents shall be of recognised analytical grade. 5.1 Water, according to EN ISO 3696, grade 2. 5.2 Mono hydrated citric acid, C6H8O7 H2O, crystallised or powder, molar mass: 210,14 g. Do not use anhydrous citric acid having a different molar mass, which can partially hydrate when storing. 5.3 Citric acid solution,
= 457,17 g/l. Preferably, use a fresh home-made solution as described below. Under these conditions, the solution concentration is conventionally supposed to be equal to the necessary one, ca = 457,17 g pure citric acid per litre. SIST EN 16357:2013
EN 16357:2013 (E) 7 The solution may be used for up to, at most, one month stored in a closed, dark glass vessel. If the solution has been stored more than one week, check its concentration by any means, for example by titration with a strong base (NaOH) solution of known concentration and report the result in the formula given in Clause 8. Weigh 500 g of mono hydrated citric acid (5.2) to the nearest 0,1 g. Pour it quantitatively into a 1 l measuring vessel. Rinse the weighing material and pour the rinsing water into the vessel in a way that it takes any acid stuck on the edge or on the bottom. Add about 500 ml of water (5.1) to the measuring vessel. Heat the vessel until full dissolution (temperature about 80 °C). Let the vessel cool to ambient temperature. Make up to the volume with water to 1 l. Stir to get a homogeneous solution. The pure citric acid content, ca, (C6H8O7), in grams per litre of this solution is calculated according to Formula (1) as follows. 17,45714,21014,192500=×=caρ (1) where 500
is the added mass of mono hydrated citric acid (5.2), in grams; 192,14 is the molar mass of anhydrous citric acid, in grams; 210,14 is the molar mass of mono hydrated citric acid, in grams. 5.4 Calcium carbonate, precipitated (or PCC), mass fraction, w(CaCO3) at least 99 %. Commercial PCC for analysis is granted for its chemical characteristics. However, physical characteristics are not granted. As reactivity depends on fineness, even for PCC, it is essential to take as a reference a highly reactive PCC, such as commercial PCC from VWR / Prolabo / BDH, reference GPR, Rectapur, Ref 22296.294, Molar mass 100,09 1), which will consume 15 ml after 15 min. This PCC was used in the ring test before launching measurements. By experience, some PCC do not meet this requirement. See also the note in 7.2.6. 5.5 Silicone defoamer. 5.6 Standard buffer solution, pH 4 (commercial solution, pH 4,01). NOTE This solution has a limited lifetime. 5.7 Standard buffer solution, pH 7 (commercial solution, pH 6,98). NOTE This solution has a limited lifetime. 6 Sampling and sample preparation 6.1 General Sampling is not part of the methods specified in this document. A recommended sampling method is given in EN 1482-1. Sample preparation shall be carried out in accordance with EN 1482-2.
1) This substance 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. SIST EN 16357:2013
EN 16357:2013 (E) 8 This document specifies that samples are tested “as received” in order to allow immediate starting of all the necessary measurements (NV, MgO). No preliminary determination is required to calculate tested sample mass. However, make sure that sample moisture is the same in the reactivity test portion as in the neutralising value measurement. Correcting factors are to be applied later on in the expression of results: actual citric acid concentration, exact mass of sample, as received neutralising value, MgO content. Such a procedure shortens the total necessary time for analysis because required measurements are made simultaneously, instead of successively. However, additional uncertainty introduced by the correction factors is not described in this document. Precision data mentioned in Clause 9 do not take into account this additional uncertainty. All implemented correction factors should be evaluated to quantify the additional uncertainty they introduce to expression of the reactivity. NOTE This procedure is also better than drying the sample first and then titrate, because drying can perhaps modify fineness or physical presentation and consequently reactivity of some products. 6.2 Preparation of the test sample Measure the moisture content of the tested material in accordance with EN 12048 and record the result for information. Make sure there is no oxide or hydroxide in the material to be tested (pH with 1/10 dilution shall be below pH 10). An oxide or hydroxide fraction in the product will bias the result. Oxide or hydroxide chemical forms are not included in the scope of this method. Use the test sample without any further preparation, e.g. grinding or drying. NOTE The procedure (7.3.2) includes a standardized time of preliminary stirring. 6.3 Preparation of the test portion Weigh 5,0 g of the test sample as received to the nearest 0,01 g, between 4,8 g and 5,2 g and record it. For liming materials coarser than 1 mm, or presenting a presumable heterogeneousness, the test portion shall be prepared fraction wise in accordance with Annex A, and a test portion of 10 g shall be taken instead of 5 g. This can happen even if material particle size is finer than 1 mm. Keep in mind that representativeness of the product as delivered
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