1、BRITISH STANDARD Liming materials Determination of calcium content Oxalate method The European Standard EN 13475:2001 has the status ofa British Standard ICs 65.080 BS EN 13475:2002 Wk present to the responsible European committee any enquiries on the interpretation, or proposals for change, and kee
2、p the UK interests informed; monitor related international and European developments and promulgate them in the UK. - A list of organizations represented on this committee can be obtained on request to its secretary. Cr oss-r e fer enc e s The British Standards which implement international or Europ
3、ean publications referred to in this document may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electronic Catalogue. A British Standard does not purport to include all the neces
4、sary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This document comprises a front cover, an inside front cover, the EN title page, pag
5、es 2 to 9 and a back cover. The BSI copyright date displayed in this document indicates when the document was last issued. O BSI 29 January 2002 ISBN O 580 38978 2 EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 13475 November 2001 ICs 65.080 English version Liming materials - Determination of
6、calcium content - Oxalate method Amendements minraux basiques - Dtermination de la teneur en calcium - Mthode Ioxalate Calcium-/Magnesium-Bodenverbesserungsmittel - Bestimmung des Calciumgehaltes - Oxalatvetfahren This European Standard was approved by CEN on 29 September 2001 CEN members are bound
7、to comply with the CENKENELEC 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 Manag
8、ement 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 Management Centre has the same status as the o
9、fficial versions. CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION EU
10、ROPISCHES KOMITEE FR NORMUNG COMIT EUROPEN DE NORMALISATION Management Centre: rue de Stassart, 36 B-1050 Brussels O 2001 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13475:2001 E EN 13475:2001 (E) Contents Page . 3 . 4 Foreword
11、 1 Scope . 2 Normative references .4 .4 .4 4 Reagents . . 5 5 Apparatus . 6 6 . 6 7 . 8 8 8 9 3 Sam pl i ng . . Precis i on . 10 Test report . . 9 2 EN 13475:2001 (E) Foreword This European Standard has been prepared by Technical Committee CEN/TC 260, Fertilizers and liming materials, the Secretaria
12、t 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 May 2002, and conflicting national standards shall be withdrawn at the latest by May 2002. According to the CENKENELEC In
13、ternal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerla
14、nd and the United Kingdom. 3 EN 13475:2001 (E) 1 Scope This European Standard specifies a method for the determination of the calcium content of silicate liming materials including slags. NOTE 1 The method has been shown to be suitable for other liming materials too, but there are no precision data
15、available yet. NOTE 2 The method is also applicable for the determination of the calcium content of mineral fertilizers. 2 Normative references This European Standard incorporates by dated or undated reference, provisions from other publications. These normative references are cited at the appropria
16、te places in the text, and the publications are listed hereafter. For dated references, subsequent amendments to, or revisions of any of these publications apply to this European Standard only when incorporated in it by amendment or revision. For undated references the latest edition of the publicat
17、ion referred to applies (including amendments). EN 1482, Sampling of solid fertilizers and liming maferials. IS0 331 0-1, Tesf sieves - Technical requiremenfs and fesfing - Part 1: Tesf sieves of mefal wire clofh. 3 Principle After dissolution of the sample in a mixture of hydrochloric acid and nitr
18、ic acid, calcium is precipitated in the form of calcium oxalate at a pH between 4,4 and 4,6. The supernatant solution is removed by means of an immersion filter. The calcium oxalate precipitate is dissolved in sulfuric acid and the calcium content is determined by titration with potassium permangana
19、te. 4 Reagents 4.1 General Commercially available standard solutions may be used instead of standard solutions produced in the laboratory. Variations in concentration shall be taken into account for the calculation of the results. 4.2 Hydrochloric acid, mo(HCI) = 1 ,I9 g/mI, c(HCI) = 12,5 mol/l. 4.3
20、 Nitric acid, m0(HN03) = 1,40 g/ml, c(HN03) = 14,9 mol/l. 4.4 Citric acid solution Dissolve 300 g of citric acid monohydrate in water and make up to 1 I. 4.5 Ammonium chloride solution Dissolve 1 O0 g of ammonium chloride in water and make up to 1 I. Mix well. 4.6 Bromocresol green Dissolve 5 g of b
21、romocresol green in ethanol with a volume concentration of ethanol of 96 % and make up to 1 I. 4 EN 13475:2001 (E) 4.7 Ammonium oxalate solution, saturated Dissolve sufficient ammonium oxalate monohydrate (approximately 70 g) in 1 I of water to produce a saturated solution. After reaching saturation
22、, filter the solution. 4.8 Ammonia solution Dilute 400 ml of ammonia solution containing a mass fraction of NH3 of 25 % m0(“3) = 0,91 g/mI with water to 1 I. 4.9 Ammonium oxalate solution Dissolve 10 g of ammonium oxalate monohydrate in water and make up to 1 I. 4.10 Sulfuric acid, nO(HzSO4) = 1,84
23、g/ml, c(H2S04) = 15,2 mol/l. 4.11 Sulfuric acid solution Dilute one volume of sulfuric acid (4.10) with one volume of water 4.12 Potassium permanganate solution, c(KMn04) ! 0,02 mol/l. Dissolve 3,18 g of potassium permanganate in 100 ml of water by boiling for 20 min. Subsequently filter the solutio
24、n through a glass filter crucible (5.3) and transfer the filtrate into a Iight-protected 1 I volumetric flask. Rinse the filter crucible. Transfer the washing water into the 1 I volumetric flask likewise and dilute to the mark. After a standing time of several days filter the solution through a filt
25、er crucible (5.3). Determine the exact amount-of-substance concentration (F) of the potassium permanganate solution using the sodium oxalate (4.1 3). 4.13 Sodium oxalate Weigh, to the nearest 1 mg, 250 mg to 300 mg of sodium oxalate into a 300 ml conical flask. Dissolve the salt in approximately 100
26、 ml of water and mix with 30 ml of sulfuric acid (4.10). Heat the solution in a boiling water bath and titrate immediately with the potassium permanganate solution until it turns to a weak pink colour. NOTE any moisture. Subsequently, the dried salt is cooled to ambient temperature in a desiccator f
27、or at least 30 min. Although sodium oxalate is not very hygroscopic it is expedient to dry the salt at 130 “C for 1 h prior to use to remove 5 Apparatus Usual laboratory equipment and in particular the following: 5.1 Water bath 5.2 Immersion filter, diameter 35 mm, porosity grade P 16 (IO pm to 16 p
28、m). 5.3 Glass filter crucible, porosity grade P 40 (16 pm to 40 pm). 5.4 Electric hot plate 5.5 Pipette filler, with a rubber expansion bulb. 5.6 Vacuum pump or water jet filter pump 5.7 Test sieve with nominal aperture size of 250 vm, according to IS0 3310-1. 5 EN 13475:2001 (E) 6 Sampling Sampling
29、 shall be carried out in accordance with EN 1482. 7 Procedure 7.1 Preparation 7.1.1 Preparation of the test sample Dry the test sample at (105 f 2) “C to constant mass. Record the as-received and dry masses and calculate the moisture content. Grind the sample so that it passes the 250 pm sieve (5.7)
30、. Mix thoroughly and store the sample in an airtight container. 7.1.2 Preparation of the test solution Weigh to the nearest 0,001 g about 1,0 g of the test sample (prepared in accordance with 7.1.1) into a 600 ml beaker. NOTE portion taken may be increased. In the case of materials of low silicic ac
31、id content with low amounts of Ca0 (less than 5 % Cao), the mass of the test Suspend the sample with 100 ml of water and add 25 ml of hydrochloric acid (4.2) and 5 ml of nitric acid (4.3). Cover the beaker with a watch glass. Boil gently for 30 min shaking several times and replacing evaporated wate
32、r. Subsequently cool and transfer the contents of the beaker to a 500 ml volumetric flask. Dilute to the mark with water and mix. Filter through a dry filter, discarding the initial portion. Store this test solution in a stoppered flask if the determination is not to be carried out immediately. 6 EN
33、 13475:2001 (E) 7.2 Determination 7.2.1 Aliquot portion Take an aliquot portion according to Table 1 Table 1 -Aliquot portions Expected Ca0 content % Aliquot ml 200 1 O0 1 O0 1 O0 Volume of burette ml 10 10 25 50 7.2.2 Titration Place the aliquot portion (7.2.1) into a 400 ml beaker, add 10 ml of ci
34、tric acid solution (4.4) and 5 ml of ammonium chloride solution (4.5). Heat the solution to boiling, add 10 drops of bromocresol green (4.6) and 30 ml of hot ammonium oxalate solution (4.7), stirring slowly and continuously. Then neutralize with ammonia solution (4.8) under constant stirring until t
35、he colour of the indicator changes from yellow to blue-green (pH 4,4 to pH 4,6). Allow the beaker to stand on a boiling water bath (5.1) for at least 30 min. Cool and remove the supernatant solution through an immersion filter (5.2). Wash the precipitate with 50 ml of cold ammonium oxalate solution
36、(4.9) and subsequently, three times with 50 ml of cold water, sucking off the wash solution each time. Add to the precipitate, without removing the immersion filter, 100 ml of water and subsequently approximately 4 ml of sulfuric acid solution (4.11) and dissolve under heating while blowing twice th
37、rough the immersion filter by means of a pipette filler (5.5). Titrate the hot solution (min. 60 OC) with potassium permanganate solution (4.12) while blowing air through the immersion filter several times by means of the pipette filler until a lasting pink colour is obtained. 7.2.3 Blank titration
38、Titrate the same amount of water as used in the above titration (see 7.2.2) with the addition of 4 ml of sulfuric acid solution (4.1 1) but omitting the test solution. 7 EN 13475:2001 (E) 8 Expression of results 1 ml of 0,02 mol/l potassium permanganate solution (4.12) corresponds to 2,002 mg Ca. Th
39、e calcium content w(CaO), expressed as mass fraction calcium oxide (Cao) in percent, is given by equation (1): (Vi - VO) * F * 14,02 w(Ca0) = m where vo is the volume of the potassium permanganate solution (4.12), in millilitres, used in the blank titration (7.2.3) ; VI is the volume of the potassiu
40、m permanganate solution (4.12), in millilitres, used in the titration of the test solution (7.2.2); F is the amount-of-substance concentration of the potassium permanganate solution (4.12) in moles per litre; m is the mass of the test portion, in grams, contained in the aliquot portion (7.2.1); 14,0
41、2 is % of the molar mass of calcium oxide. The calcium content of the product as received w(CaO), is given by equation (2): w(Ca0). (100 - w,) 1 O0 w(CaO), = where w(Ca0) is the calcium content, given as mass fraction calcium oxide (Cao) in percent, of dry material see equation (I); WM is the moistu
42、re content of the test sample (7.1 .I), given as mass fraction in percent. To express the results in % Ca use equation (3): w(Ca) = w(Ca0). 0,7147 (3) 9 Precision 9.1 General The values derived from interlaboratory tests with eight participating laboratories are shown in 9.2 and 9.3. 8 EN 13475:2001
43、 (E) 9.2 Repeatability The absolute difference between two single test results obtained with the same method on identical test material in the same laboratory by the same operator using the same equipment within the shortest feasible time interval will exceed the repeatability limit r in not more th
44、an 5 % of cases. The values are - r = 0,64 % (mass fraction) for blast furnace slags with w (Cao) = 42,O %; - r = 1 ,O1 % (mass fraction) for converter slags with w(Ca0) = 48,6 %. - NOTE w (Cao) is the mean mass fraction of calcium oxide. 9.3 Reproducibility The absolute difference between two singl
45、e test results, obtained with the same method on identical test material in different laboratories with different operators using different equipment, will exceed the reproducibility limit R in not more than 5 % of cases. The values are - R = 1,516 % (mass fraction) for blast furnace slags with w (C
46、ao) = 42,O %; - R = 1,516 % (mass fraction) for converter slags with w (Cao) = 48,6 %. - NOTE w (Cao) is the mean mass fraction of calcium oxide. 10 Test report The test report shall contain at least the following information: a) all information necessary for the complete identification of the sampl
47、e; b) a reference to this European Standard; c) the results and the units in which the results have been expressed; d) any particular points observed in the course of the test; e) any operations not specified in the method or regarded as optional which may have affected the results. 9 BS EN 13475:20
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