Method and apparatus for producing diammonium phosphate with external circulation ammoniation reactor

A process for preparing diammonium phosphate with ammoniating reactor using external recirculating uses such apparatuses as ammoniating reactor using external recirculating, Venturi washer, material slurry tank and material slurry circulation system. The tail gas after reaction can be discharged after washed through Venturi washer where concentrated phosphoric acid is used as washing liquid. Saidwashing liquid is added to reactor from its top, where it takes part in neutralizing reaction with ammonia. The part of material slurry overflowed from reactor to material slurry tank is used to spray granulation and the rest is pumped back to reactor for increasing the flowability of materials. Its advantages include short technological route, high utilization rate of ammonia, stable running andnot being blocked easily.