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Drying and storage of npk granular fertilisers based on superphosphate and containing urea as a plant nutrient
Author(s) -
Jewell R. E.
Publication year - 1962
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.2740130803
Subject(s) - urea , chemistry , ammonium , nitrogen , granule (geology) , ammonium nitrate , moisture , agronomy , nitrate , organic chemistry , materials science , composite material , biology
In an investigation of the properties of NPK fertilisers which contain urea as a plant food, the effects of free moisture, free acidity, urea content and temperature on their stability during storage have been studied. It is concluded that to ensure complete stability of NPK fertilisers (N 10, P 2 O 5 , 10, K, 2 O 18%) containing superphosphate and urea (2‐15%). Other conclusions are that ( a ) losses of nitrogen during storage are negligible, and that ( b ) insoluble phosphates formed during storage are in ‚available’ forms as determined by the neutral ammonium citrate test. (1) a maximum granule temperature of 70°G is preferable during the drying process, although temperatures up to 90°G could be tolerated if the drying time is limited to about 15 min. (2) for incorporation with urea, ammonium sulphate is somewhat preferable to ammonium nitrate, as it gives a more stable product (3) the fertilisers should be stored at 35° or lower.