Ammonia → Ammonium dihydrogen phosphate

The FIGURE shows a schematic view of an embodiment of the present invention. Anhydrous ammonia 14 flows from holding tank 12 through conduit 16 and into reactor 18. Phosphoric acid 24 flows through conduit 22 from holding tank 26 and into reactor 18 where the anhydrous ammonia and phosphoric acid are partially reacted to form a reaction product slurry 30 comprising monoammonium phosphate and diammonium phosphate. The slurry 30 is pumped to a rotating drum granulator-reactor 32 where more anhydrous ammonia 34, from holding tank 33, is added in order to complete the production of diammonium phosphate from the monoammonium phosphate. The moisture containing diammonium phosphate 35 exists from the granulator-reactor 32 and is transferred to a rotating drum dryer 36. During the drying process, excess moisture is removed resulting in a dry and solid granulator diammonium phosphate product mixture. A portion 40 of the dried product mixture 38 is diverted without regard to particle size through conduit 42 back to the granulator-reactor 32. The portion of the dried product not diverted 44, is transferred through conduit 48 to the classifying means 50, such as a set of screens, to separate the oversize 52 and undersize or fines 56 from the desired product 54. The oversize 52 is transferred through conduit 58 to a mill 59 which reduces the oversize particle. The fines 56 are collected on tray 51 during the separation process. The milled oversize 60 is transferred along with the fines 56 back to the granulator-reactor 32. The desired product size 54 of 2 to 4 mm is collected and stored or packaged.