Large Volume Inorganic Chemicals - Ammonia ... - ammk-rks.net

Chapter 77.2 Applied processes and techniques7.2.1 OverviewFigure 7.1 gives an overview of the production of NPK fertilisers. Compound fertilisers can beproduced in four, basically different, ways:• production by the mixed acid route, without phosphate rock digestion• production by the mixed acid route, with phosphate rock digestion• production by the nitrophosphate route (ODDA process)• mechanical blending or compactation of single or multi-nutrient components (not includedin the figure).M i x e d a c i d r o u t eNitrophosphate route(ODDA process)NH 3H 2SO 4/H 3PO 4and/or HNO 3HNO 3NH 3H 2SO 4, H 3PO 4, HNO 3Phosphate rockDirectneutralisation(pipe reactor)Preneutralisation(tank)Phosphaterock digestionPhosphaterock digestionSand removalSand removalMixed acidslurryCa(NO 3) 2crystallisationand filtrationVariousamounts of:• NH 3• urea/(NH 4 ) 2 SO 4• AN solution•H 2 SO 4•H 3 PO 4•HNO 3• SSP/TSP• MAP/DAP•H 2 O/steam•K salts• other nutrients• fillersNeutralisation,evaporation,adjustment ofcompositionParticle formationand conditioning“NP acid”NH 3 /CO 2Ca(NO 3) 2.4 H 2OConversionNH 4NO 3/CaCO 3NPK fertiliserTo NPK, AN, CAN orCN productionFigure 7.1: Overview of the production of NPK fertilisers from phosphate rock or SSP/TSP[154, TWG on LVIC-AAF, 2006]Large Volume Inorganic Chemicals – Ammonia, Acids and Fertilisers 285