| 摘要 |
There is disclosed a process to produce fertilizer granules containing urea and ammonium sulfate with a high ammonium sulfate concentration of <=60 wt. % in a fluidized bed granulator, which process comprises the steps of: a) a molten urea suspension consisting of ammonium sulfate having an average particle size of 30 to 300 mum and urea having a temperature range of 120 to 155° C. is produced, b) the molten urea suspension produced at the stage a) is then injected from below on the fine particles of urea/ammonium sulfate in a fluidized bed granulator by means of at least a nozzle, while the fluidized bed is loosened by a spouting air flow in the injection area, and subsequently, c) the fertilizer granules generated in the fluidized bed are separated and, if necessary, treated. Homogeneous urea/ammonium sulfate granules of an ammonium sulfate content between 30 and 60 wt. % can be produced this way without any problems, while the particle size of granules can be adjusted selectively and dust emissions by granulation can be reduced to a minimum.
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