NPK fertilizer refers to chemical fertilizers with nitrogen (N), phosphorus (P), and potassium (K) as the main nutrients. Small NPK fertilizer production lines typically involve multiple key steps aimed at mixing and processing these basic ingredients and other auxiliary materials into granular fertilizers that are easy to store and use. The following are the core granulation steps of a small-scale NPK fertilizer production line:

Raw material pretreatment: Firstly, the solid raw material is crushed into fine powder, and NPK and other additives (such as trace elements such as sulfur, magnesium, zinc, etc.) are accurately weighed according to the formula. The liquid composition needs to be measured and kept as a backup.

Mixing: Put powdered NPK components and other solid raw materials into a high-speed mixer to ensure uniform distribution of each component and form a homogeneous mixture.

Granulation: Use a fertilizer granulator to make granules. There are two common ways:

Disc granulation: Wet the mixture with water, pour it into a rotating disc granulator, and use centrifugal force to form spherical particles.

Squeezing granulation: using high pressure to squeeze the mixture through a mold, then cutting it into cylindrical or sheet-like particles of a certain size, and then crushing them into the desired size.

Drying: After granulation, the particles need to enter a dryer to reduce moisture content, prevent clumping, and maintain stable physical properties of the fertilizer.

Cooling: The dried particles will be sent to a cooling tower or cooler for rapid cooling, preventing the quality of fertilizers from being affected by high temperatures.

Screening: The cooled particles are passed through a vibrating screen to remove oversized or undersized non-conforming particles, ensuring the consistency of the product's particle size.

Coating treatment (optional): To extend the shelf life of fertilizers and enhance moisture resistance, a protective layer such as wax or resin can be applied to the surface of particles.

Packaging: The final step is to weigh, package, label, and prepare the finished product for shipment or storage.

Quality inspection: Strict quality testing should be conducted throughout the entire production process, including before the finished product, to ensure that every bag of NPK fertilizer meets the standards.

Although the small-scale NPK fertilizer production lines is small, each process is indispensable, and precise coordination is necessary to produce high-quality products. Proper operation and maintenance of equipment, optimization of process parameters, are key to ensuring efficient operation of production lines.