The formation of NPK granules by prilling using nitrophosphate-type processing is practiced quite widely in Europe. In this process the NPK mixture (solution) is concentrated to approximately 96%-98% solids before it is introduced to the top of the prilling tower through either a nozzle assembly or a perforated vessel referred to as a “prilling bucket.” The nozzle or prilling bucket assemblies are designed to produce droplets of the “molten” fertiliser mixture that, upon solidification, will yield the desired granule (prill) size. NPKs produced by the prillinq process are very homogeneous with respect to nutrient content. However, due to the practical limitations of the drop formation and solidification process, prilled NPK products usually exhibit a smaller particle (granule) size, typically 1.3 – 3.0 mm in diameter, than do NPKs produced by other granulation processes.

Links to related IFS Proceedings and presentation recordings

109, (1969), Prilling of Compound Fertilisers,
F E Steenwinkel, J W Hoogendonk.

136, (1973), Ammonium Nitrate Production,
G Drake.

285, (1989), Development and use of an On-Line Particle Analyser in a Prilling or Granulation Plant,
W Frydenberg.

768, (2015), Controlling Particulate Emissions from Ammonium Nitrate Prill Production, J H B Guimarães, S A Ziebold, J M Hanekom.

803, (2017), Changes, challenges, and opportunities in fertiliser-manufacturing processes: A personal review and outlook,
H Reuvers.