NPK fertilizers, the "nutritional cornerstone" of agricultural production, are produced through an industrial process that scientifically combines three core elements: nitrogen, phosphorus, and potassium. From natural raw materials to standardized finished products, the NPK fertilizer production process involves multiple precise steps to ensure balanced nutrients and stable fertilizer efficacy.

Raw material pretreatment is the foundation of production. Nitrogen sources typically use urea or ammonium nitrate, phosphorus sources come from monoammonium phosphate and diammonium phosphate processed from acid-digested phosphate rock, and potassium sources are derived from potassium salts such as potassium chloride or potassium sulfate. These raw materials are first stored in dedicated silos.  Agglomerated materials are crushed by a crusher, and then screened through a vibrating screen to obtain uniform particles.Simultaneously, magnetic separation equipment removes metal impurities, ensuring the purity of the raw materials. Before entering the mixing stage, an automatic batching system precisely proportions the materials according to a preset formula. The automated metering system controls the nutrient ratio error to within 0.5%, laying a solid foundation for subsequent mixing.
Mixing and granulation are key stages in nutrient integration. The pretreated raw materials are fed into a double axis mixer, where a small amount of binder such as bentonite is added and mixed at high speed.  Then, the mixture enters a rotary drum granulator. As the drum continuously rotates, a spray system evenly sprays atomized water or dilute phosphoric acid, and the materials gradually agglomerate into 2-4 mm particles. The particle size can be flexibly controlled by adjusting the drum speed and water spray volume.
Drying and cooling determine fertilizer stability. The newly formed wet granules have a high moisture content and must be immediately sent to a drum fertilizer dryer. Under the action of 120-150℃ hot air, the moisture is rapidly evaporated to below 2%. The dried granules, with a temperature exceeding 80℃, then enter a cooler, where they undergo countercurrent heat exchange with cold air, cooling to room temperature to prevent high-temperature moisture absorption and agglomeration, while also improving particle strength.
Screening and quality inspection are the final checks before shipment. After cooling, the granules are classified using a vibrating screen.  Qualified granules are sent to the finished product warehouse, while unqualified fine powder or large lumps are crushed and recycled for reprocessing, resulting in a raw material utilization rate exceeding 98%. The finished product also undergoes spectroscopic testing to verify nutrient content and ensure compliance with national standards.
From raw material selection to finished product warehousing, the precise control at every step of the NPK fertilizer production line ensures the scientific proportioning and efficient utilization of nutrients in NPK fertilizers, providing reliable nutritional support for crop growth.