NPK compound fertilizers, characterized by balanced nutrients and broad applicability, serve as a cornerstone of modern agricultural production. A standardized, automated NPK compound fertilizer production line requires a complete process flow—encompassing pretreatment, batching and mixing, granulation, drying and cooling, screening and packaging, and environmental treatment—supported by specialized, synchronized equipment to ensure consistent quality and efficient, compliant production. The entire equipment suite comprises six core systems covering the full production cycle.

The raw material pretreatment and batching system forms the foundation of the production line, determining the precision of the fertilizer formula. Key equipment includes uniform feeders, chain crushers, and automatic batching systems. Raw materials such as urea, ammonium phosphate, and potash are prone to caking; chain crushers pulverize these lumps into fine powder (finer than 80 mesh) to ensure uniform mixing in subsequent stages. The automatic batching system features multi-bin batchers and electronic scales, enabling precise proportioning of raw and auxiliary materials with a metering accuracy of ±0.5%. This ensures strict control over NPK nutrient ratios, making it suitable for producing standard formulas like 15-15-15.
The mixing and granulation system is the core stage for fertilizer shaping, directly influencing the granule formation rate. Batched materials are fed into a double shaft paddle mixer or a horizontal ribbon mixer; high-speed agitation ensures the uniform blending of nutrients, achieving a mixing uniformity of over 95%. Granulation equipment is selected based on production scale: small-to-medium lines utilize double-roller press granulators for dry granulation (requiring no water), while large-scale lines typically employ rotary drum granulators. The latter rely on the principle of rolling agglomeration to produce round, full granules with a qualification rate exceeding 90%, making them ideal for continuous, large-scale production.
The drying, cooling, and screening system is responsible for optimizing granule quality. Freshly formed granules have high moisture content and must be fed into a drum dryer, where hot air circulation reduces moisture to prevent caking or deterioration. Since the dried granules are hot, a drum cooler is used to rapidly lower the temperature to below 50°C, preventing high temperatures from compromising storage stability. The material then enters a drum screening machine to separate out standard finished granules (2–6 mm); the screened-out powder and oversized waste particles can be recycled for re-pulverizing and re-granulation, achieving zero raw material waste.
The finished product handling and packaging system ensures standardized product output. Qualified granules can undergo an optional anti-caking coating process to extend shelf life. Finally, a fully automatic quantitative packaging machine integrates weighing, sealing, and bundling operations; compatible with various bag specifications and featuring a high degree of automation, it effectively enhances packaging efficiency and precision.
In addition, the production line is equipped with auxiliary environmental protection and central control systems. A pulse bag dust collector captures dust generated during production, minimizing material loss and ensuring compliance with dust emission standards, while exhaust treatment equipment purifies waste gases to meet environmental regulations. A PLC central control system enables centralized monitoring of equipment operating parameters and fully automated regulation, ensuring stable, efficient, and continuous production line operation.
The entire NPK compound fertilizer production line features clearly defined roles and seamless integration, forming a closed-loop process from raw material handling to finished product dispatch. Balancing production efficiency, product quality, and environmental compliance, it serves as the core foundation for the industrial-scale production of high-quality compound fertilizers. To meet the full-cycle needs of establishing and launching a compound fertilizer plant, Huaqiang Heavy Industry offers professional, reliable, one-stop services. Leveraging mature equipment R&D and manufacturing technologies alongside extensive project experience, the company provides comprehensive solutions—including site planning, customized process design, full-set equipment manufacturing, on-site installation and commissioning, technical training, and after-sales maintenance. These services cater to diverse production capacity and formulation requirements, empowering enterprises to achieve efficient startups and stable production while eliminating the complexities of coordinating with multiple vendors, thereby safeguarding the success of compound fertilizer manufacturers.