Comparison of Different Granulation Processes in NPK Fertilizer Production Lines

The core of an NPK fertilizer production line lies in its granulation process. Different granulation methods directly affect fertilizer particle morphology, nutrient utilization rate, and production line configuration. Currently, the mainstream granulation processes include rotary drum granulation, disc granulation, extrusion granulation, and high-tower granulation, each suited to different production scenarios. Rotary drum granulation is the most widely used process. It relies on the internal rotational friction of the drum granulator to form materials into granules, featuring high output and rounded particles. The complete NPK fertilizer production line includes equipment such as fertilizer granulators, dryers, coolers, screening machines, mixers, and packaging machines. It has a mature structure, stable operation, and is suitable for most compound fertilizer enterprises. Disc granulation offers higher precision and better pelletizing rate, making it suitable for small to medium-sized production volumes. It also requires less floor space and has lower investment costs. Extrusion granulation is a room-temperature physical granulation process that does not require high-temperature drying, thus better preserving the nutrients in the raw materials. It is often used in conjunction with equipment such as crushers, mixers, roller extrusion granulators, and screening machines, and is suitable for the production of slow-release fertilizers and high-concentration NPK fertilizers. High-tower granulation produces uniform granules with high hardness and good solubility, but requires a larger investment in equipment. Regardless of the process chosen, the NPK fertilizer production line needs to be configured based on the characteristics of the raw materials, production volume requirements, and product positioning. A proper combination of the fertilizer granulator and upstream/downstream equipment is essential for the efficient and stable operation of the entire production line.