Principle of drum granulator
The drum granulation method is a method of mixing and granulating powdered basic fertilizers with a drum granulator, and is widely used in the granulation of compound fertilizers. Principle: First, each basic fertilizer is screened separately, and the screened material is crushed by a crusher and then screened. The undersieve is sent to their respective hoppers. When the granulation system is in operation, the basic fertilizers are simultaneously sent from their respective hoppers to the feeding hopper via metering equipment, conveying equipment and lifting equipment according to the proportioning requirements. At the same time, the returned material enters the hopper together with the basic fertilizer through the lifting equipment.
The basic fertilizers and returned materials are mixed to a certain extent in the process of transportation and lifting, but it is more ideal if a mixing device can be added. The mixture in the hopper is fed to the drum granulator at a certain feeding speed. At the same time, properly pass saturated steam under the material layer, which not only increases the temperature of the material, but also humidifies the material, which is beneficial to granulation. If necessary, sprinkle a small amount of water or fertilizer solution on the material to maintain the proper humidity for the material granulation. The material forms a rolling material bed by the friction generated by the rotation of the drum granulator. The extrusion force generated by the rolling makes the material containing a certain liquid phase agglomerate into small particles. These small particles become the core and adhere to the surrounding powder Form larger particles. Since the fertilizer granulator machine is generally inclined 1°~2.5° to the discharge end, the granules slowly roll toward the discharge port while rotating with the cylinder body. Qualified pellets leave the drum granulator and then enter the dryer for drying, and then undergo screening, cooling, coating, packaging and storage. After being crushed, the on-screen material and the under-screen material are sent to the hopper as the return material and the basic fertilizer is simultaneously granulated.