Characteristics and granulation of slow controlled release compound fertilizer granules
After pelletizing and coating in NPK fertilizer production process, the compound fertilizer has the advantages of slow release and controlled release, at the same time, it also avoids fertilizer caking and is more convenient for storage and use.
A complete NPK fertilizer production line includes batching, mixing, granulation, drying, cooling, coating, screening and other processing. Fertilizer granulator machine is an important equipment to produce NPK compound fertilizer, which is the key to turning fertilizer into particles. NPK fertilizer production line can usually use rotary drum granulator or disk granulator, both of which are formed by agglomeration. However, in order to smoothly become a spherical particle, the disc granulator must be added with an adhesive material or a slurry. Once the limit is exceeded, the drum granulator can only be used. Other fertilizer granulator machine can only be used. The output of the drum granulator is larger.
A fertilizer coating machine is added in the final processing stage of NPK fertilizer production line, so that the fertilizer particles have controlled-release characteristics. The coating machine processes the granules, which greatly improves the controlled release properties of the fertilizer. The release process of coated controlled release fertilizer nutrients is as follows:
1.In the first step, water permeates into the membrane, and the membrane is expanded by water to produce micropores, including fine structures at the molecular level.
2.In the second step, water enters the membrane and nutrients are dissolved.
3.In the third step, water permeates into the membrane, and under the effect of the water vapor pressure difference, nutrients diffuse to the outside of the membrane through microporous channels. With the decrease of the concentration of nutrient solution in the membrane, the vapor pressure inside and outside the membrane gradually decreased, and the release rate gradually decreased.
Advantages of Slow and Controlled Release Compound Fertilizer Particles
1. The controlled-release fertilizer can basically eliminate the loss of nutrients in the soil, such as leaching, degradation, volatilization, etc., and can largely avoid the biological, physical and chemical fixation of nutrients in the soil.
2. The controlled-release fertilizer can basically meet the needs of large-scale production of modern agriculture, saving labor, time and labor. A large amount of application at a time will not cause damage to crop roots; the nutrient utilization rate is high, and the environmental pollution is small.