Disc Granulation Process
Npk Fertilizer Dryer Machine
Working Principle: Materials roll on a rotating disc and gradually form granules by spraying binders and other means. The rotation of the disc makes the materials continuously tumble and agglomerate. During this process, the binder bonds the fine raw material powders together, and the granules are continuously compacted and become more solid during the rolling process.
Characteristics: The equipment has a simple structure, is easy to operate, and has a relatively low investment cost. It can produce granules with relatively uniform particle size and is suitable for granulating a variety of raw materials. However, the production efficiency is relatively low, and the strength of the granules may not be as high as that produced by some other granulation processes.
Rotary Drum Granulation Process
Working Principle: Materials move inside a rotating rotary drum. As the drum rotates, the raw materials are lifted and tumbled within the cylinder. During this process, by spraying binders or adding certain liquid-phase raw materials to the raw materials, the raw materials gradually agglomerate into granules. Factors such as the rotation speed and filling rate of the drum have a great impact on the granulation effect.
Characteristics: It has a strong production capacity, good roundness of granules, and stable product quality. It can handle a wide range of raw materials and is suitable for large-scale production. However, the equipment is relatively complex, occupies a large area, and requires high control of operating parameters.
Extrusion Granulation Process
Working Principle: Using pressure to extrude pretreated powdered raw materials through a specially designed mold into strip shapes, and then cutting the strip materials into granules of a certain length. During the extrusion process, the frictional force and extrusion force between the raw materials make them closely combined.
Characteristics: The granules produced by this process have high hardness, regular shapes, and are not easily broken. It can well control the size and shape of the granules and is especially suitable for some raw materials that are not easy to agglomerate. However, the molds of the extrusion equipment are prone to wear, and the production efficiency may be limited by the molds.
Slurry Spraying Granulation Process
Working Principle: The slurry containing fertilizer nutrients is sprayed into the granulation equipment (such as a rotary drum or slurry spraying granulation tower) through a spray head. Inside the equipment, the slurry comes into contact with the return materials (previously unqualified granules) or other solid raw materials. Under the action of hot air or other drying media, the water in the slurry evaporates, the solute crystallizes and wraps around the surface of the solid granules, gradually forming granules.
Characteristics: It can produce high-concentration compound fertilizers. The granules have good strength and wear resistance. The product quality is excellent, and the nutrient distribution is uniform. However, the equipment investment of this process is large, the energy consumption is high, and strict requirements are imposed on the operation technology and process control.
High Tower Granulation Process
Working Principle: The high-temperature molten slurry is sprayed down from the spray head at the top of the high tower. During the free fall process inside the tower, the slurry meets the rising cold air. Through air cooling, the slurry solidifies and forms granules. During this process, due to factors such as the surface tension of the slurry and the air resistance, the granules will form relatively regular spherical shapes.
Characteristics: The granules produced have a round and beautiful appearance, uniform particle size, high strength, and good solubility. This process can produce quickly with high production efficiency. However, the high tower equipment is expensive to build, and extremely high requirements are imposed on the production stability.
