Nitrogen, phosphorus, and potassium (NPK) granular fertilizers are the "nutritional cornerstone" for crop growth. NPK  production lines require specialized equipment across multiple stages to achieve efficient operation from raw material processing and precise proportioning to shaping, processing, and final packaging. This ensures stable fertilizer quality and suitability for large-scale production.

Raw material pretreatment equipment is the basic guarantee of production. NPK raw materials are mostly in block or crystalline form.  Crushers are used to pulverize hard raw materials such as potassium chloride to the specified particle size, and vibrating screens are used for coarse and fine grading. Unqualified materials are returned for reprocessing to prevent damage to subsequent equipment. Closed silos are used to store various single fertilizers and auxiliary materials, with screw conveyors for automated transfer, preventing raw materials from absorbing moisture and clumping.
Precise batching and mixing equipment determine the balance of nutrients in the fertilizer. The automatic batching system precisely delivers nitrogen, phosphorus, and potassium raw materials and trace elements according to the preset formula. Powdered and granular raw materials are adapted to screw and belt conveyors respectively, and small-proportion auxiliary materials use loss-in-weight feeders, with a metering accuracy of up to ±0.3%. Double axis mixers are suitable for small and medium-sized production lines, while gravity-free mixers are suitable for large-scale production, enabling thorough mixing of multi-component raw materials. In some cases, a pre-mixer is needed to ensure uniform dispersion of trace elements.
Granulation and drying/cooling equipment are the core components of the NPK fertilizer production line's molding process. Granulation methods commonly use rotary drum granulators and disc granulators, while extrusion methods use roller extrusion granulators, which do not require a drying step and are suitable for heat-sensitive raw materials. After granulation, a rotary dryer is needed to remove moisture. Three-pass dryers have a thermal efficiency increase of more than 30% compared to single-drum models.  Then, a drum cooler reduces the granule temperature to below 40℃ to ensure storage stability.
Finished product processing and environmental protection equipment complete the production cycle. A double-layer vibrating screen separates unqualified granules for recycling, and high-end products can be coated with anti-caking agents using a coating machine. Fully automatic packaging machines complete quantitative filling, and palletizing equipment improves efficiency. Environmental protection equipment such as scrubbers and desulfurization devices are also required to treat dust and waste gas generated during production, meeting green production requirements.
In summary, a granular NPK fertilizer production line requires the appropriate combination of specialized equipment for each stage, taking into account raw material purity, nutrient balance, and granule formation quality.  Simultaneously, the inclusion of environmentally friendly equipment ensures compliance with green production requirements, fully supporting the efficient advancement of the NPK fertilizer production process. A rationally matched equipment combination with appropriate production capacity can effectively improve production efficiency, guarantee product standardization, and facilitate the large-scale supply of granular fertilizers.