Patent ID: 6179893
Filing Date: 2001-01-30
Classification: C05C

Abstract:
A process for producing fertilizer granules containing urea and ammonium sulfate and having an ammonium sulfate concentration .ltoreq.60 wt. %, comprising the steps of: forming a molten urea suspension consisting of ammonium sulfate having an average particle size of 30 to 300 .mu.m and urea having a temperature range of 120 to 155.degree. C.; forming a fluidized bed of fine urea/ammonium sulfate particles in a fluidized bed reactor; injecting the molten urea suspension upwardly into the fluidized bed in an injection area while maintaining air flow into the injection area to loosen the fluidized bed, performing granulation and forming fertilizer granules and inadvertent dust; dividing the dust by dry separation into a fine ammonium sulfate lean fraction and a coarse ammonium sulfate rich fraction and returning the coarse ammonium sulfate rich fraction to the fluidized bed and/or uniting the coarse ammonium sulfate rich fraction with the molten urea suspension after wet-milling the coarse ammonium sulfate particles prior to granulation; separating the fertilizer granules generated in the fluidized bed; and, if necessary, treating the separated fertilizer granules.