The Role of Binders in the Production of Fertilizer by Fertilizer Granulators

Binder refers to a substance that promotes the agglomeration of raw material powder and particles during the granulation process, improves the granulation efficiency, increases the yield, and improves the physical properties of the granules (strength, surface morphology, disintegration resistance, etc.). In wet granulation such as rotary drum granulator, disc granulator, and stirring granulator, granulating liquid such as water is added to the raw material powder to make the surface of the powder wet and form solid-liquid crosslinks. Reunite into pellets. On the other hand, in dry granulation, such as briquetting granulation and melt granulation, since the granulation is completed by intermolecular forces, there is no need to add a granulation binder.

The principle of drum granulation is that materials rely on surface tension, an appropriate amount of liquid phase, extrusion force generated by rolling between materials, and small particles are taken as the core in the correct movement direction of materials in the granulator to absorb large particles and adhere to small particles and form balls during rolling. The higher the rolling frequency in a certain time, the higher the balling rate and the rounder the particles are after forming.
The organic fertilizer rotary drum granulator used in small and medium-sized fertilizer plants is a rotating circular granulator with a diameter of 1.2 - 2.4m and a length of 3 - 6m. A material retaining ring is arranged at the feeding end and the middle part of the simplified body, and the tail is smooth. The middle retaining ring of the organic fertilizer drum granulator divides the simplified body into two areas, the front area is the mixing granulation area, and the rear area is the particle polishing area.

The granulation binder used in the fertilizer granulation process should have the following functions:a. Certain adhesion
b. High surface tension
c. High solid crosslinking strength after drying
d. Low cost
e. When mixed with chemical fertilizers, it is harmless to crops
f. Biodegradability of synthetic organic materials