Production of NPK Fertilizers with a Spouted Bed Granulator-Dryer

Agrimont set up a technology producing NPK fertilizers based on granulation_drying of ammoniated slurry from nitric attack of phosphate or sulphurric-phosphoric acid mixture carrying out a research work on a micro-pilot and pilot plant. The commercial plant based on said technology has been operating for 5 years in the Priolo factory (Sicily), producing DAP, NP frtilizers by nbitirc attack of phosphate rock (15-30-0), NPK fertilizers with potassium sulphate (20-10-10, 12-24-12, 15-15-12) and with potassium chloride (15-15-15). The production capacity of the Priolo plant, based on a single spouted bed, ranges from 500 to 700 t/D according to the product grade and water balance. The performances obtained with the spouted bed process are compared with the drum granulation process here below. The main features of the spouted bed process are the simple flowsheet involving lower investment and production costs, ease to run and control by automatic devices. The total investment cost for a plant based on the spouted bed process and with a capacity of 180,000 to 200,000 tons/year of NPK fertilizers is estimated at US $ 10.5 million (about 20% less than an equivalent plant based on the rotary drum process). The yearly economic advantage for the spouted bed process is about US $ 900,000, mainly due to the lower investment and direct costs.