Features of NPK Extrusion Granulation Technology

NPK extrusion granulation is a mainstream dry granulation technology in compound fertilizer production. With its advantages of simple process, low energy consumption, and no nutrient loss, it is widely used in the large-scale production of high-concentration compound fertilizers. This process eliminates the water addition and drying steps of traditional wet granulation, relying solely on mechanical pressure to complete powder forming. It is suitable for various nitrogen, phosphorus, and potassium powdered raw materials and is a highly efficient and environmentally friendly fertilizer production process.

The core principle of this process is dry extrusion molding. Precisely proportioned nitrogen, phosphorus, and potassium powdered raw materials are thoroughly mixed and fed into a double roller press granulator. Mechanical pressure is applied by a pair of opposing, equally rotating pressure rollers. The pressure of the extrusion rollers can be adjusted from 10-25 MPa according to the material characteristics, squeezing out air from the gaps between the materials, allowing the powder to tightly adhere and agglomerate, forming a dense and flat sheet-like material. The entire process requires no added water or binders, fundamentally preventing nutrient loss and material deterioration.

The complete production process consists of four steps, with simple and efficient procedures. First, the raw materials are precisely proportioned and mixed according to the fertilizer formula, ensuring homogeneity. Second, high-pressure extrusion molding transforms the powder into dense flakes. Next, the flakes are crushed and shaped into irregular granules. Finally, the granules are graded and sieved to separate those of acceptable size, while unqualified powder and crushed material are recycled for reprocessing, achieving raw material recycling with a molding rate exceeding 95%.

Compared to traditional processes, NPK extrusion granulation offers significant advantages. It eliminates the need for high-temperature drying, effectively protecting heat-sensitive nutrients and ensuring stable and precise fertilizer nutrient content. The process is short, equipment maintenance is simple, and energy consumption and production costs are significantly reduced. The finished granules have moderate hardness, are not prone to clumping, and have good water solubility, making them suitable for mechanized fertilization operations. Furthermore, this process generates no wastewater or exhaust gas emissions, making it environmentally friendly and meeting the low-carbon production requirements of modern agriculture.

Today, the NPK extrusion granulation process has been continuously optimized and upgraded, adapting to the production of multiple types and high-concentration compound fertilizers, taking into account yield, quality and environmental benefits. It has become the preferred production process for small and medium-sized fertilizer enterprises, helping the fertilizer industry to improve quality and efficiency and achieve green transformation and development.