Common organic fertilizer granulation processes include: drum granulation, disc granulation, spray granulation and high tower granulation, while organic fertilizer granulation mainly adopts drum granulation, disc granulation and roller granulation, and the main measurement indicators are qualified granulation rate and large ball rate.

Double roll extrusion granulation integrates the processes of powder extrusion molding, crushing and finished product screening, with compact structure and convenient operation. The powder is continuously and evenly added from the hopper to the top of the two rolls. Under the continuous rotation of the extrusion roll, the powder is bitten between the two rolls and extruded into sheet metal, and then falls off under the centrifugal action and the gravity of the sheet metal itself, until the shaping wheel with toothed claws is separated into particles by striking, and then enters the sorting screen. The powder under the screen is sent back to the return material, and the particles on the screen are rolled by the drum, the acute angle of the particles is ground, and the particles flow out of the discharge port on the screen bucket into the packaging. The bearing support on the moving side of the roll is equipped with a spring. With the help of the deformation of the spring, the support moves in balance, and the distance between the two rolls is adjusted to maintain the required extrusion pressure. Extrusion granulation is suitable for high, medium and low concentration fertilizers without drying and normal temperature production.