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An investigation into the caking of granular fertilizers
Author(s) -
Mitchell W. A.
Publication year - 1954
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740050912
Subject(s) - caking , sublimation (psychology) , potassium , ammonium chloride , chemistry , ammonium , recrystallization (geology) , chloride , materials science , inorganic chemistry , chemical engineering , organic chemistry , geology , psychology , paleontology , psychotherapist , engineering
Compound granular fertilizers frequently cake during storage, making even distribution difficult. An investigation into this problem by X‐ray crystallographic and optical methods showed that interaction occurred between the ingredients during manufacture, with the formation of ammonium chloride from ammonium sulphate and potassium chloride. During drying the ammonium chloride is concentrated at the surface of the granules by sublimation. Small needle‐shaped crystals of ammonium chloride grow outwards from the granules in the presence of moisture, and this recrystallization is the cause of caking. To prevent caking, thorough drying is necessary, but high temperatures should be avoided as they would increase the surface concentration of ammonium chloride by sublimation.