There are several main methods for granulation of organic fertilizers:

1.Agglomeration method
Disc granulation： This is one of the common methods for granulation of organic fertilizers. Its working component is a tilted disk with adjustable angle and speed. During operation, the friction force generated by the bottom and inner wall of the disk drives the material to move in the circumferential direction. The particles are squeezed and rubbed against each other, and due to the difference in particle mass, different gravity and centrifugal forces are generated, causing the particles to automatically classify. Large particles float on the surface of the rolling inclined layer, while small particles sink below, forming their own motion trajectories. When the biological agent is sprayed and moistened on the surface of the core particles, the core particles converge and attach more and finer particles, gradually growing and increasing in mass. When the centrifugal force is sufficient to overcome the frictional force, the particles are thrown out of the disc to become the desired product. This method is intuitive and simple, with a high granulation rate, uniform particle size, automatic grading, low unit power consumption, and less material return. However, it requires high material mixing uniformity and fineness, and there is a small amount of dust overflow.
Drum granulation： Granulation is achieved through the rotation of a cylinder. Its single machine cost is high, but it has high productivity, no dust overflow, and low requirements for material mixing uniformity.

2.Extrusion method
Roll squeezing granulation: composed of two relatively rotating rolling rolls, the material is subjected to squeezing force between the two rolling rolls to form strip-shaped or sheet-like particles. This method is suitable for a variety of materials, especially those with low moisture content, and has the advantages of high production efficiency, regular particle shape, and high density. However, the equipment wears out significantly and requires regular maintenance and replacement of components.
Flat die extrusion granulation: using a flat die for extrusion granulation, the die has multiple holes, and the material is extruded into the holes to form particles. The particles produced by this method are generally cylindrical in shape, and the particle diameter can be adjusted according to the size of the mold holes. The particle density is high, making it suitable for producing organic fertilizers with small particles. However, the output of the flat die extrusion granulator is relatively low, and the mold is prone to wear and blockage, requiring timely cleaning and maintenance.


In summary, there are multiple methods to choose from for organic fertilizer granulation, each with its unique characteristics and applicable scenarios. In actual production, the appropriate granulation method should be selected based on factors such as raw material properties, production scale, product quality requirements, and economic benefits. At the same time, continuously optimizing process parameters and equipment performance to improve the production efficiency and product quality of organic fertilizers.