Extrusion granulation is a production method that two or more basic fertilizers are crushed and stirred uniformly to form granular compound fertilizer by extrusion machine with less water content. Extrusion fertilizer granulator machine usually has two types, one is double roller extrusion granulator, the other is flat die extrusion granulator. The two fertilizer granulators have different types because of their different structure.
Flat Die Extrusion Granulator
When materials enter the flat-die granulator, the water content is usually 5%-8%. Cylindrical particles are obtained after extrusion. NPK compound fertilizer products with water content less than 5% are obtained by drying and cooling. The granulation rate of the fertilizer granulator is usually about 85%.
The feed water content of the double roller granulator can be lower. The strip material obtained by extrusion can be screened by double-layer screening inside the machine to get bulk or angular compound fertilizer products. The crushed fine powder can be transported through NPK fertilizer production line and returned to the machine for granulation, and the large particles can be returned to the crusher for crushing. Because of the low moisture content of the product of the double roller fertilizer granulator, the drying process can be omitted. Extrusion granulator is widely used in NPK fertilizer production, with short process flow, low operation cost, no drying and other treatment of raw materials, low operation cost (if using traditional granulation technology such as disc or drum, drying cooling system is needed).
In the production process of NPK fertilizer, the materials to be crushed should be carefully screened to prevent copper, iron, stones and other hard objects from entering the crushing chamber and causing accidents.
When conveying materials, they should stand on the side of the crusher to prevent rebounding debris from injuring the face. During the working period of fertilizer machinery, we should pay attention to its operation at any time, uniform feeding, in order to prevent congestion, not long overload operation. If there are vibration, noise, high temperature of bearing and body, outward spraying and other phenomena, stop immediately to check, after troubleshooting can continue to work.