Process for granulating ammonium phosphate containing fertilizers

Abstract

A process for granulating ammonium phosphate containing composition for use as a fertilizer which comprises feeding a slurry or melt of ammonium phosphate, wherein said slurry or melt is capable of further reaction with ammonia, into a kneading mill, feeding recycled particles from the subsequent classification and crushing procedure into said kneading mill, wherein the said slurry or melt added to the mill is from 5 to 95% wt. of the total slurry or melt, feeding ammonia into said mill to react with at least a portion of the reactable components of said slurry or melt, generating a heat of reaction, subjecting said mixture to a kneading action within said mill until the heat of reaction and the kneading action cause a repeated disposition of fertilizer material onto the solids and cause a repeated drying of said deposit, passing the product from said kneading mill into a rotary drum granulator, feeding additional ammonium phosphate containing slurry or melt to a said granulator in an amount of from 95% to 5% wt. based on the total slurry or melt, feeding additional amounts of ammonia to said granulator wherein at least a portion of the reactable components of said slurry or melt is reacted, giving off a heat of reaction, subjecting said mixture to a rotary action until said heat of reaction and tumbling action of the rotary granulator effects a further deposition of fertilizer material onto the solids, passing the product from said granulator into a dryer so as to remove excess water, subjecting said dried product to a classification apparatus so as to separate out particles which are outside the product size range, recycling at least a portion of said particle mixture to said kneading mill, and recovering said dried particles of product size. Commensurate apparatus is provided to perform said process.