BS ISO 23381:2020 pdf free.Determination of salt out (crystallization)temperature of liquid fertilizers.
This document specifies the test procedure for the determination of the salt out temperature (SoT)also known as the crystallization temperature (CT) of liquid (fluid) fertilizers,using an inexpensiveand simple technique.
This method might not be applicable to the binary and ternary fertilizers, especially with regards to thelast crystal to disappear (LCTD).Some of these exceptions are discussed in the procedure (Clause 8).
The following referenced documents, in whole or in part, are normatively referenced in this documentand are indispensable for its application. For dated references,only the edition cited applies.Forundated references, the latest edition of the referenced document (including any amendments) applies.
An aliquot of the original liquid fertilizer sample is placed into a glass test tube and is then immersedinto an alcohol-dry ice bath until it crystallizes. The alcohol could be chosen from methanol, ethanol,or isopropanol (IPA).Acetone could also be used instead of alcohols; however,IPA (rubbing alcohol)is preferred due to its higher boiling point. If dry ice is not available, other lowering temperaturemixtures such as salt-ice could be used to achieve the proper cooling and crystallization of the fertilizertest sample.
Once the precipitation (formation of salt crystals) is complete, the cooling source is removed and theglass test tube and its contents are allowed to warm up to room temperature. The SOT in most casesis defined when the last crystal to dissolve (LCTD) dissolves (i.e. is no longer visible in the solution).Exceptions to the LCTD rule are covered below and in 8.11.
Affix the test tube containing the test sample with a three-pronged clamp and position such thatthe thermometer end containing the stainless steel wire is placed inside and centred on the test tube.Make sure the thermometer is almost to the bottom of the test tube, but not touching it; this is done toensure that almost all the forming crystal will mix and not settle on the test tube bottom.
Make sure the thermometer can rotate and adequately stir the sample in the test tube withouttouching the sides and the bottom of the test tube.
As the thermometer stirs the solution in the test tube, take the Dewar flask of alcohol/dry ice andplace it around the test tube.Make sure all of the tube containing the test sample is immersed fully intothe alcohol/dry ice solution to ensure even cooling.BS ISO 23381 pdf download.