Understanding how fertilizers are made helps farmers, students, and industry teams make better choices about quality and safety. This guide maps the Top 10 Fertilizers Manufacturing Process Flows from Raw Materials to Finished Granules in simple language, while keeping important technical details. You will see how basic inputs like ammonia, acids, potash, and rock phosphate travel through reactors, granulators, dryers, coolers, and screens to become uniform granules ready for the field. Each flow highlights raw materials, key chemical steps, critical equipment, recycle streams, and quality controls. The goal is clear insight, from feed preparation to final packaging and storage.
#1 Urea granulation flow from ammonia and carbon dioxide
Urea starts with ammonia and carbon dioxide that react at high pressure to form ammonium carbamate, which dehydrates to urea solution. The solution is concentrated in vacuum evaporators to the prill or granulation melt. In fluidized bed or drum granulators, sprayed melt builds uniform granules around seed particles while recycled fines and crushed oversize close the size loop. Hot granules pass through a rotary dryer, then a cooler to stabilize hardness. Screens classify product, with offsize returned to the granulator. Anti caking agents or polymer coatings improve handling. Final steps include dust recovery, emissions scrubbing, and automated bagging.
#2 Ammonium nitrate prilling and high density granules
Ammonium nitrate forms when ammonia neutralizes nitric acid in a controlled neutralizer to reach target acidity and water content. The hot solution is concentrated to melt in vacuum concentrators with safety interlocks. Prilling towers create spherical prills by spraying melt downward through a rising air stream, or a drum granulator builds dense HDAN granules using seeds and recycle fines. Dryers remove residual moisture, and coolers prevent caking. Additives such as clay, dolomite, or coatings enhance stability. Multiple screens ensure tight size distribution. Dust is captured by cyclones and scrubbers. Product moves to silos or bags with temperature monitoring.
#3 Diammonium phosphate slurry to robust DAP granules
DAP production combines ammonia and phosphoric acid to form an ammoniated phosphate slurry in a pipe reactor or attacked in a granulator. Recycle fines and seed material help instant nucleation as fresh slurry sprays in. The tumbling bed grows granules to specification while steam helps maintain the right viscosity. Rotary dryers remove water, setting hardness and crush strength. Cooling protects against caking before screening trims the size band. Offsize material is milled and recycled. Online analyzers track nitrogen, P2O5, moisture, and granule size. Dust and fluoride emissions are scrubbed. Finished DAP is coated, stored, and bagged.
#4 NPK compound fertilizer via drum or spray granulation
NPK compounds integrate nitrogen, phosphate, and potash in one granule. Raw feeds can include urea or ammonium nitrate, phosphoric acid or monoammonium phosphate, and muriate of potash. In drum or pan granulation, liquid binders and chemical reactions create a cohesive matrix around recycle seeds. Pipe reactors may pre form ammoniated phosphate for stronger granules. After granulation, drying sets mechanical strength, cooling stabilizes, and screening fixes the size curve. Minor nutrients and conditioners can be sprayed for micronutrient enrichment. Process controls manage moisture, temperature, and recycle ratios. Coating reduces dust and caking. Final product goes to silos.
#5 Single superphosphate curing and granulation from rock
SSP begins with ground phosphate rock reacting with sulfuric acid to form monocalcium phosphate and gypsum. The pasty mass moves along a den to complete reaction, then cures in a storage hall to achieve plant available P and workable texture. The cured cake is milled and fed to a granulator with water or weak acid as binder, where recycle fines help build granules. Dryers reduce moisture, coolers prevent caking, and screens lock in particle size. Dust is recovered to the recycle loop. Quality checks verify available P2O5, free acid, and hardness. Product is coated, stored, and dispatched.
#6 Triple superphosphate from phosphoric acid to hard granules
TSP uses phosphate rock and concentrated phosphoric acid to produce a higher analysis monocalcium phosphate. In attack reactors, acid wets and reacts with rock under controlled temperature and residence time. The material discharges to a curing hall where conversion completes and crystal structure matures. After curing, the cake is crushed and fed to a drum granulator with water or dilute acid to form granules around seeds. Drying and cooling develop crush strength and stability. Screens trim size; fines and oversize return to the loop. Dust and fluoride gases are scrubbed. Granules are coated, stored, and bagged.
#7 Calcium ammonium nitrate densification and cooling sequence
CAN combines ammonium nitrate melt with finely ground limestone or dolomite. The neutralized and concentrated AN melt is sprayed into a granulator where mineral filler acts as seed and improves safety and storage properties. Controlled recycle maintains bed inventory and target size. Dryers remove moisture to reach set water and porosity levels. Coolers reduce temperature to below crystallization thresholds that cause caking. Multi deck screens select the product window, returning offsize to crushing and recycle. Anti caking or hydrophobic coatings improve flow in humid climates. Emission controls capture ammonium nitrate dust. Product moves to silos or bags.
#8 Potassium chloride compaction and dry granulation route
Muriate of potash often uses a dry route. Screened KCl is conditioned for moisture and particle size, then fed to a roll compactor that compresses powder into dense flakes without liquids. Flakes are milled to granules and classified by screens to achieve a consistent size. Fines recycle to the compactor feed, while oversize returns to the mill. A gentle cooler reduces temperature from compaction heat, improving storage behavior. Optional water or brine sprays can reduce dust, followed by drying if used sparingly. Final steps include dedusting, coating to reduce caking, mechanical sampling for size analysis, and bulk or bag loading.
#9 Sulfate of potash by Mannheim furnace and granulation
The Mannheim process reacts potassium chloride with sulfuric acid in a refractory lined furnace. First stage forms potassium bisulfate while releasing hydrogen chloride gas captured in absorbers. Second stage converts to potassium sulfate as temperature and residence time are controlled by paddle mixers. The hot SOP discharges to cooling and milling, then enters a granulator with water or solution binders to form strong granules. Dryers reduce moisture, coolers stabilize, and screens refine size. Recycle closes the mass balance. Offgases pass through acid resistant scrubbers. Product may be conditioned with anti caking agents before storage and shipment.
#10 Coated and controlled release urea granule finishing
Controlled release urea starts from standard urea prills or granules. For sulfur coated urea, molten sulfur sprays onto warm urea in a rotating drum, followed by a wax or polymer sealant to heal pores. For polymer coated urea, fluidized beds or drums apply successive thin polymer layers that govern nutrient release. Coating weight, uniformity, and defects are checked by dissolution and crush tests. Conditioners reduce dust and improve flow. Screens remove agglomerates, with rework routed to reclaim. Final handling uses gentle conveyors, temperature control, and lined bins to protect the coating. Product is packed with clear release labeling.