Taking a common drum granualtor as an example, during operation, the pre-treated (crushed, mixed) organic fertilizer raw materials enter an inclined rotating drum. As the drum rotates, the material continuously tumbles and collides under the action of gravity and centrifugal force. Simultaneously, water or natural binders (such as wood ash slurry, starch liquid) are added through a spray system to moisten the surface of the material, causing the fine particles to gradually agglomerate and form initial small granules. These small granules continue to roll inside the drum, constantly adsorbing surrounding powder, gradually growing larger like a snowball, eventually forming uniformly sized spherical granules.
Extrusion granulators, on the other hand, force materials into a die cavity through a screw conveyor or roller extrusion. High pressure binds the material particles tightly together, and the resulting granules are cut into columnar or block-shaped pieces. No additional moisture is needed, making them suitable for raw materials with low moisture content.
While different types of organic fertilizer granulators may have different structures, they all revolve around the core principle of "agglomeration and shaping," transforming dispersed organic fertilizer raw materials into granular products that are easy to store, transport, and apply, while retaining the nutrients and active ingredients of the organic fertilizer.
