Process for granulating ammonium phosphate containing fertilizers

  • US 4,154,593 A
  • Filed: 02/16/1977
  • Issued: 05/15/1979
  • Est. Priority Date: 08/27/1976
  • Status: Expired due to Term
First Claim
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1. A process for granulating an ammonium phosphate containing composition for use as a fertilizer which comprises:

  • feeding a slurry or melt of ammonium phosphate containing less than 20 wt.% water, 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 at a recycle ratio of 2;

    1 to 4.5;

    1,wherein the said slurry or melt added to the mill is from 25 to 75% wt based on the total slurry or melt which is to be granulated,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 deposition 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 having a water content of less than 20 wt.% to said granulator in an amount of from 75 to 25% based on the total slurry or melt which is to be granulated,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 drier 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, andrecovering said dried particles of product size.

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