Fertilizer production defines an area of industrial activity to produce compounds of nitrogen, phosphorus and potassium (N/P/K), in different proportions, depending on their use and the numerous processes for their production.
Among these are the family of ammonium phosphate based fertilizer such as MAP and DAP. To meet the demand for this type of products are used manufacturing facilities, where the main process is the digestion of phosphate rock using a combination of HNO3, H2SO4 and/or H3PO4 and with the addition of NH3 during the process.
Main areas of gas emission are the reactor and the granulator. The main pollutants are NH3, VOC’s and dust. The solution adopted consists of an initial stage of venturi–cyclon for dust removal, followed by an acidic scrubber to remove NH3 and a final alkaline scrubber step to remove HF (if present). Also in the case of DAP, due to the strong presence of NH3, it is removed by the recirculation of a H3PO4 solution to obtain (NH4)3PO4 which, once crystallized, can be used as fertilizer.