The granulation process in the fertilizer industry is a crucial step in transforming raw materials into granular products. It relies heavily on fertilizer granulators and consists of three stages: pretreatment, molding, and post-treatment.

In the pretreatment stage, raw materials such as urea and monoammonium phosphate are crushed to 1-3mm, mixed according to the formula, and the moisture content is adjusted (10%-20%). A binder is added in some cases to lay the foundation for granulation.

The molding stage is the core. The fertilizer granualtor is selected based on the characteristics of the raw materials: rotary drum granualtors are suitable for large-scale production, agglomerating the raw materials into round granules; double roller press  granualtors do not require additional moisture, relying on high pressure to press the raw materials into molds, suitable for high-concentration fertilizers and heat-sensitive fertilizers (such as bio-organic fertilizers), producing high-strength granules; disc grnaualtors are flexible in operation and suitable for small- to medium-scale production and specialty fertilizers.

In the post-treatment stage, the wet granules are dried (moisture content reduced to 3%-5%), cooled, and then sieved to separate qualified granules of 2-6mm. The fine powder is returned for reprocessing. Some products also feature a coating to enhance performance.

The entire process is monitored by an intelligent system, with the precise operation of fertilizer granulators (especially specialized equipment such as roller extrusion granulators) ensuring that the granule strength and uniformity meet standards, making the fertilizer easier to store, transport, and apply, and adaptable to different agricultural needs.