In organic fertilizer production, the granulator is the core equipment that determines the product's shape, quality, and production capacity. Different granulators are suitable for different raw material characteristics and production needs. Currently, the mainstream equipment is mainly divided into four categories.

Disc granulators are the "main force" in small and medium-sized organic fertilizer plants. They rely on a tilting rotating disc to roll and granulate wet-based fermented materials (such as livestock manure and straw mixtures) with a moisture content of 25%-40%. Their advantages include simple structure, low cost, convenient operation and maintenance, and high sphericity and good appearance of the produced granules; however, the single-unit capacity is relatively low, suitable only for production scales of less than 1 ton per hour, and strict control of raw material moisture is required, otherwise, sticking to the disc is likely to occur.
Rotary drum granulators are the first choice for medium to large-scale production. When the long cylindrical drum rotates, the raw material fully tumbles and agglomerates inside the drum. A single unit can achieve an hourly output of 1-10 tons, meeting the needs of continuous production lines. It is suitable for various fermented organic fertilizer and compound fertilizer raw materials, producing uniform and stable granules. However, the equipment is large in size, occupies a large area, and has a higher investment cost than disc granulators. It also requires complete pre- and post-processing procedures.
Extrusion granulators are designed specifically for low-moisture raw materials and come in two types: roller and ring die. For dry powder raw materials with a moisture content below 15% (such as dried organic fertilizer powder and peat moss), it directly extrudes the material into granules using mechanical pressure, eliminating the need for extensive drying and resulting in low energy consumption. The produced granules are hard, not easily broken, and easy to store and transport. However, the granules are mostly flat round or cylindrical, with lower roundness, and require a raw material fineness of at least 80 mesh.
In addition, new granulation equipment can meet special needs. Flat die pellet mills are suitable for small-scale production and high-fiber raw materials (such as sawdust), with adjustable granule length.
Choosing a granulator requires considering production capacity, raw materials, and pellet requirements: small plants should choose disc granulators, while medium and large plants should choose drum granulators; wet materials should be selected from disc or drum granulators, while dry materials should be selected from extrusion granulators; if appearance is important, choose disc or drum granulators, and if hardness is important, choose extrusion granulators. Reasonable selection can improve production efficiency.