1、BSI Standards PublicationBS ISO 17322:2015Fertilizers and soil conditioners Analytical methods forSulfur Coated Urea (SCU)BS ISO 17322:2015 BRITISH STANDARDNational forewordThis British Standard is the UK implementation of ISO 17322:2015. The UK participation in its preparation was entrusted to Tech
2、nicalCommittee CII/37, Fertilisers and related chemicals.A list of organizations represented on this committee can be obtained on request to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The B
3、ritish Standards Institution 2015.Published by BSI Standards Limited 2015ISBN 978 0 580 76662 6ICS 65.080Compliance with a British Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 June
4、2015.Amendments/corrigenda issued since publicationDate T e x t a f f e c t e dBS ISO 17322:2015 ISO 2015Fertilizers and soil conditioners Analytical methods for Sulfur Coated Urea (SCU)Matires fertilisantes Mthodes analytiques pour lure enrobe de soufre (SCU)INTERNATIONAL STANDARDISO17322First edit
5、ion2015-06-01Reference numberISO 17322:2015(E)BS ISO 17322:2015ISO 17322:2015(E)ii ISO 2015 All rights reservedCOPYRIGHT PROTECTED DOCUMENT ISO 2015, Published in SwitzerlandAll rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized otherwise in any fo
6、rm or by any means, electronic or mechanical, including photocopying, or posting on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address below or ISOs member body in the country of the requester.ISO copyright officeCh. de Blandonne
7、t 8 CP 401CH-1214 Vernier, Geneva, SwitzerlandTel. +41 22 749 01 11Fax +41 22 749 09 47copyrightiso.orgwww.iso.orgBS ISO 17322:2015ISO 17322:2015(E)Foreword vIntroduction vi1 Scope . 12 Normative references 13 Sampling and sample preparation 14 Determination of the appearance . 15 Determination of t
8、he mass fraction of total nitrogen 16 Determination of 1DDR and 7DDR 16.1 Titrimetric method after distillation 16.1.1 Principle 16.1.2 Reagents 16.1.3 Apparatus . 26.1.4 Procedure . 26.1.5 Calculation . 26.2 Refractometer method . 36.2.1 Principle 36.2.2 Reagents 36.2.3 Apparatus . 36.2.4 Procedure
9、 . 46.2.5 Calculation . 57 Determination of the mass fraction of sulfur . 67.1 Principle 67.2 Reagents 67.3 Apparatus 67.4 Procedure 67.4.1 Determination of the sulfur content . 67.4.2 Blank test 77.5 Calculation 78 Determination of the mass fraction of biuret . 78.1 Principle 78.2 Reagents 88.3 App
10、aratus 88.4 Procedure 88.4.1 Preparation of the calibration curve. 88.4.2 Preparation of the solution to be analysed . 98.5 Calculation 99 Determination of the water content 109.1 Principle . 109.2 Reagents. 109.3 Apparatus . 109.4 Installation and test of the Karl Fischer titrator .109.5 Procedure
11、. 119.5.1 Standardization of the Karl Fischer reagent .119.5.2 Determination .119.6 Calculation . 119.6.1 Water equivalent of the Karl Fischer reagent 119.6.2 Water content of the sample . 1210 Determination of particle size.1211 Precision 1211.1 Ring test . 12 ISO 2015 All rights reserved iiiConten
12、ts PageBS ISO 17322:2015ISO 17322:2015(E)11.2 Repeatability 1211.3 Reproducibility 1312 Test report 13Annex A (informative) Interlaboratory testing 14Bibliography .48iv ISO 2015 All rights reservedBS ISO 17322:2015ISO 17322:2015(E)ForewordISO (the International Organization for Standardization) is a
13、 worldwide federation of national standards bodies (ISO member bodies). The work of preparing International Standards is normally carried out through ISO technical committees. Each member body interested in a subject for which a technical committee has been established has the right to be represente
14、d on that committee. International organizations, governmental and non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.The procedures used to develop th
15、is document and those intended for its further maintenance are described in the ISO/IEC Directives, Part 1. In particular the different approval criteria needed for the different types of ISO documents should be noted. This document was drafted in accordance with the editorial rules of the ISO/IEC D
16、irectives, Part 2 (see www.iso.org/directives).Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights. ISO shall not be held responsible for identifying any or all such patent rights. Details of any patent rights identified during the dev
17、elopment of the document will be in the Introduction and/or on the ISO list of patent declarations received (see www.iso.org/patents).Any trade name used in this document is information given for the convenience of users and does not constitute an endorsement.For an explanation on the meaning of ISO
18、 specific terms and expressions related to conformity assessment, as well as information about ISOs adherence to the WTO principles in the Technical Barriers to Trade (TBT), see the following URL: Foreword Supplementary information .The committee responsible for this document is ISO/TC 134, Fertiliz
19、ers and soil conditioners. ISO 2015 All rights reserved vBS ISO 17322:2015ISO 17322:2015(E)IntroductionSulfur Coated Urea (SCU) is a coated, slow release fertilizer consisting of urea particles coated with sulfur, which was first developed by the Tennessee Valley Authoritys National Fertilizer Devel
20、opment Center (TVA/NFDC), Alabama in 1961, and produced commercially in 1967. SCU is made by coating urea with sulfur and sealant. It contains 30 % to 40 % nitrogen and 10 % to 30 % sulfur. The main coating material of SCU is sulfur. Sulfur is insoluble in water and its chemical properties are stabl
21、e, thus, it is an impermeable coating material. In addition, sulfur itself is a secondary nutrient and it does not pollute the soil.This International Standard specifies analytical methods, including mass fraction of total nitrogen, one-day dissolution rate (1DDR), seven-day dissolution rate (7DDR),
22、 mass fraction of sulfur, mass fraction of biuret, mass fraction of water (H2O), and SGN and UI of SCU. There are two methods for determining of one-day dissolution rate (1DDR) and seven-day dissolution rate (7DDR): one is titrimetric method after distillation, the other is refractometer method whic
23、h is a fast analytical method.NOTE Some countries or regions might have published other standards covering analytical methods for SCU.vi ISO 2015 All rights reservedBS ISO 17322:2015Fertilizers and soil conditioners Analytical methods for Sulfur Coated Urea (SCU)1 ScopeThis International Standard sp
24、ecifies analytical methods for the determination of mass fraction of total nitrogen, one-day dissolution rate (1DDR), seven-day dissolution rate (7DDR), mass fraction of sulfur, mass fraction of biuret, mass fraction of water (H2O), and particle size of SCU.These methods are applicable to SCU.2 Norm
25、ative referencesThe 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)
26、applies.ISO 760, Determination of water Karl Fischer method (General method)ISO 3310-1, Test sieves Technical requirements and testing Part 1: Test sieves of metal wire clothISO 5315, Fertilizers Determination of total nitrogen content Titrimetric method after distillationISO 17323, Fertilizers and
27、soil conditioners Sulfur Coated Urea General requirements3 Sampling and sample preparationSampling and sample preparation shall be carried out in accordance with ISO 17323.4 Determination of the appearanceIt shall be determined by visual method.5 Determination of the mass fraction of total nitrogenI
28、t shall be determined in accordance with ISO 5315.6 Determination of 1DDR and 7DDR6.1 Titrimetric method after distillation6.1.1 PrincipleDigest the testing sample in static water at a constant temperature (38,0 0,5) C. Within a certain period, the nitrogen component in the testing sample will disso
29、lve into the water through the coatings, and then the released nitrogen can be determined by titrimetric method after distillation. The percentage of released nitrogen to the total nitrogen is defined as 1DDR or 7DDR.6.1.2 ReagentsSee ISO 5315.INTERNATIONAL STANDARD ISO 17322:2015(E) ISO 2015 All ri
30、ghts reserved 1BS ISO 17322:2015ISO 17322:2015(E)6.1.3 Apparatus6.1.3.1 Common laboratory apparatus.6.1.3.2 The apparatus listed in ISO 5315.6.1.3.3 Balance, capable of weighing to the nearest 0, 01 g.6.1.3.4 Constant temperature incubator, capable of being controlled at (38,0 0,5) C.6.1.4 Procedure
31、The replicate experiments shall be done for the determination.6.1.4.1 Place 20 g uncrushed test sample (accurate to 0,01 g) into a small bag made of 100 meshes nylon yarn nets. Then, seal the bag and place it into a 250 ml Erlenmeyer flask with a plug.6.1.4.2 Add 200 ml of water into the flask preci
32、sely before the flask sealed with the plug.6.1.4.3 Shake the glass flask gently to disperse the particle of test portion. Then, place the glass flask into a constant temperature incubator with temperature set at (38,0 0,5) C and keep for 24 h and 7 d, respectively.6.1.4.4 After a set period, take ou
33、t the flask from the incubator and reverse it gently three times to ensure the uniformity of solution concentration throughout the flask.6.1.4.5 Then, cool the flask down to room temperature, and the solution should be filtrated with dry filter paper with a pore size of 30 m to 50 m.6.1.4.6 Pipette
34、5 ml of the as-prepared solution; the total released nitrogen during a 24 h and 7 d period should be determined in accordance with ISO 5315.NOTE 1 Nylon yarn nets were used herein for the convenience of filtration (large undissolved particles of SCU can be discarded together with the nylon yarn net)
35、.NOTE 2 Replicate tests during the actual operation can refer to two, three, or more tests.6.1.5 Calculation6.1.5.1 Calculate the total released nitrogen during 24 h period, w1, expressed in the mass fraction (%), according to Formula (1):wwVV110=/(1)wherew1is the total released nitrogen of the test
36、 solution pipetted during a 24 h period calculated according to ISO 5315, in the unit of mass fraction (%);V0is the volume value of the test solution pipetted during the test, in the unit of millilitre (ml);V is the total volume value of the test solution, in the unit of millilitre (ml).Express the
37、result to within two decimal places. The average value of the results of parallel tests shall be defined as the final result of the determination.2 ISO 2015 All rights reservedBS ISO 17322:2015ISO 17322:2015(E)6.1.5.2 Calculate the 1DDR, x1, as the mass fraction (%), according Formula (2)xww110100=
38、(2)wherew1is the value of the total released nitrogen during 24 h period, expressed in the mass fraction (%);w0is the value of the total nitrogen determined in accordance with the provision 5, expressed in the mass fraction (%).6.1.5.3 Calculate the total nitrogen release during 7 d, w2, expressed i
39、n the mass fraction (%), with Formula (1), prescribed in 6.1.5.1.Express the results to within two decimal places. The average value of the results of two parallel tests shall be defined as the result of the test.6.1.5.4 Calculate the 7DDR, x2, expressed in the mass fraction (%), according to Formul
40、a (3):xww220100= (3)wherew2is the value of the total released nitrogen during 7 d, expressed in mass fraction (%).6.2 Refractometer method6.2.1 PrincipleFirst, determine the solid contents in the sulfur coated urea product, and then calculate the mass of urea in the sample. Based on the feature that
41、 the mass fraction of urea (%) in a solution at a certain temperature is proportional to the refractive index of the solution, calculate the urea contents (g/l) in the solution by determining the refractive index of the solution.6.2.2 Reagents6.2.2.1 Urea solution, 200 g/l.Weigh 100 g urea, dissolve
42、 it in 250 ml water, and then dilute the solution to 500 ml and mix.6.2.3 Apparatus6.2.3.1 Ordinary laboratory apparatus.6.2.3.2 Balance, capable of weighing to the nearest 0,000 1 g.6.2.3.3 Magnetic stirring apparatus.6.2.3.4 Temperature-controlled refractometer, readability, 0,000 01RI, Accuracy:
43、0,000 05RI, temperature accuracy: 0,05 C at 20 C, thermometer resolution: 0,01 C.6.2.3.5 Constant temperature incubator, capable of being controlled at (38 0,5) C. ISO 2015 All rights reserved 3BS ISO 17322:2015ISO 17322:2015(E)6.2.3.6 Drying oven, capable of being controlled at (100 2) C.6.2.4 Proc
44、edure6.2.4.1 Preparation of calibration curve6.2.4.1.1 Preparation of the standard solutionAs shown in Table 1, pipette into a series of eight 100 ml volumetric flasks, 0,00 ml (as compensation solution), 2,50 ml, 5,00 ml, 10,00 ml, 20,00 ml, 30,00 ml, 40,00 ml, and 50,00 ml of the urea standard sol
45、ution. Make each flask up to the mark with water and mix thoroughly.Table 1 Amount of urea content per standard solution Volumes of urea standard solution/ml The corresponding urea contents/g/l0,00 0,002,50 5,005,00 10,010,00 20,020,00 40,030,00 60,040,00 80,050, 00 100,06.2.4.1.2 Preparation of the
46、 calibration curvePrior to the test, set the optimum parameters for the refractometer, following the instruction of the guidebook.Pipette 2 to 3 drops of the as-prepared urea standard solution and directly drop on the measuring disk of the refractometer, then wait for 3 min to 4 min until the temper
47、ature is stable at (30 0,1) C. Then, the refractive index of standard solutions with different concentrations can be measured and recorded.With the refractive indexes of the urea standard solutions as the ordinate, and the urea contents (g/l) in the corresponding standard solution as the abscissa, t
48、he calibration curve can be plotted, and determine the equation of linear regression.6.2.4.2 Determination of solid contents in samplesThe replicate experiments shall be done for the determination.Weigh 2 g (accurate to 0,000 2 g) of the as-prepared test sample (crushed) into a tall-type beaker, and
49、 add 100 ml of water; the system should be mixed up on a magnetic stirrer at least 2 min to form a slurry solution. Make sure that all the granules are completely crushed and the urea is dissolved completely.Place a piece of weighted filter paper into a Buchner funnel, the paper should be soaked with water and fitted to the shape of the Buchner funnel. Pour the sample containing slurry solution onto the filter paper in the Buchner funnel; the residue on the stirrer should be washed onto the filter p
