ISO INTERNATIONAL STANDARD 10248 First edition 1996-12-15 FluidfertilizersDe-aerationof suspensionsamplesbyfilmdisentrainment Engrais liquides-Désaerationdeséchantillonsdesuspensionpar entrainementencouchemince ISO Referencenumber ISO10248:1996(E) ISO10248:1996(E) Foreword ISO(the International OrganizationforStandardization)is aworldwidefederationof national standardsbodies(lsO member bodies).The work of preparing International Standards is normally carried out through IsO technical committees.Each memberbody interested in a subjectforwhicha technical committeehas been established has the right toberepresented on that committee.International organizations,governmental and non-governmental,in Commission(lEC)onallmattersofelectrotechnicalstandardization Draft International Standards adopted by the technical committees are circulated to the memberbodies for voting. Publication asan International Standard requires approval byat least75%of the memberbodies castingavote. International Standard SO10248 waspreparedbyTechnicalCommitteeISO/TC134,Fertilizersand soil conditioners,SubcommitteeSC3,Physicalproperties. ISO1996 All rights reserved.Unlessothenwise specified,no partof this publicationmaybereproduced microfilm,without permission in writing from the publisher. International Organizationfor Standardization Casepostale56.CH-1211Geneve20.Switzerland Internet [email protected] X.400 C=ch; a=400net; p=iso; 0=isocs; s=central Printedin Switzerland i ISO10248:1996(E) INTERNATIONALSTANDARDISO Fluidfertilizers-De-aerationofsuspensionsamplesbyfilm disentrainment 1Scope This International Standardspecifies a procedure forthe de-aerationof suspension samplesforphysicaltesting The method is not suitable if the sample contains more than a trace of free ammonia, if there is permanent decompositioninthesuspension,orifthesampleistooviscous. 2 Principle Samples of suspensions may involve airbeing mixed in by stirring or shaking.Often this air diffuses out of the suspension very slowly because of the viscosity. To reduce the quantity of physically incorporated air,the fromthe fluid,provision is madeforthin-filmdisentrainment.Viscosity effects arereducedto a minimum whenthe fluid moves slowly. 3Apparatus Normal laboratoryapparatusand, inparticular,thefollowingitems. 3.1Rotaryevaporator,withaminimumcapacityof1litre,capableofevacuationtoapressureof2x10*Pa. I plleu 3.2 Waterbath,capableofbeingmaintainedat25C±2℃ 1IA11A 4Procedure nAAlll Transfer about 500 g of the sample to a clean and dry 1 litre evaporator flask and weigh the flask and contents to pipnr the nearesto,1 g. 1011 inn Place thebody of the flask in the water bath (3.2)set at 25°C, NOTE1 The cooling systemof theevaporatorshould not beused, so astoavoidloss ofwaterbytemperaturedifferences. nann) NOTE2 Higher temperatures should be avoided to prevent gas production by decomposition of fertilizer ingredients,for exampleurea /107 Reducethepressureinthesystemtoabout4x10*Pa. inn an ln Operatethesystemforapproximately15min. Gentlyallowthesystem tocometo atmosphericpressurebeforedisconnecting theflask. Dry the outside of the flask and reweigh the flask and contents to the nearest o,1 g. NOTE 3The loss in mass during the process should not exceed 0,1% Take samples forphysical testing with care. If thetest is not to beperformed immediately,closetheflaskand store underambient conditions forno longerthan 3 days. 1