Working Principle and Core Structure
The disc granulator is widely used in fertilizer production, with its core working principle based on the mechanical effects generated by the rotation of an inclined disc. When the disc rotates at specific angles and speeds, materials undergo transformation from powdered raw materials to uniform granules under the combined action of centrifugal force, gravity, and friction. This “snowballing” granulation process makes disc granulators particularly important in small and medium-scale fertilizer production.
The core components of the disc granulator include the inclined disc, transmission system, spraying device, and discharge outlet. Among these, the adjustable inclined disc is the key component, with its angle changes directly affecting material residence time and particle growth rate.
Three Stages of Granulation Process
Nuclei Formation Stage
The granulation process begins with the formation of tiny nuclei. After spraying an appropriate amount of binder, powdered raw materials form approximately 0.5mm diameter micro-nuclei through mutual adsorption and agglomeration under the collision and compression effects generated by disc rotation. Binder control at this stage is crucial, as excessive amounts cause material clumping while insufficient amounts prevent effective nuclei formation.
Particle Growth Stage
During continuous rotation, nuclei continuously adsorb surrounding powder through the cyclic path of “spiral rise and fall,” gradually growing like rolling snowballs. By adjusting the disc’s inclination angle and rotation speed, particle growth rate and final particle size can be precisely controlled, achieving accurate control of the target particle size of 2-4mm.
Particle Shaping Stage
Particles that have reached the target size continue to roll within the disc. Through continuous collision and compression, the internal structure of particles becomes more compact, and surfaces become smoother. This process significantly enhances particle mechanical strength, ensuring fertilizer integrity during subsequent transportation and use.
Key Control Parameters
Inclination Angle Adjustment
The disc’s inclination angle is the most critical parameter affecting granulation effectiveness. An inclination range of 35-45 degrees typically provides optimal granulation results. Angles that are too small cause material accumulation, while angles that are too large shorten material residence time, affecting particle quality.
Rotation Speed Optimization
A rotation speed range of 15-25 rpm balances the relationship between centrifugal force and gravity, ensuring ideal material motion trajectory. Rotation speed needs to match the disc diameter, with larger diameter discs requiring relatively lower speeds.
Precise Humidity Control
Controlling material humidity within the 8%-15% range is essential for successful granulation. Appropriate humidity provides sufficient binding force without causing excessive material adhesion. Binder selection requires optimization based on raw material characteristics.
Application Advantages and Scope
Disc granulators play an important role in fertilizer manufacturing with their unique advantages. The produced particles feature high sphericity, smooth surfaces, and excellent strength, making them particularly suitable for organic fertilizer, compound fertilizer, and biofertilizer production. The equipment’s simple structure, easy operation, and convenient maintenance make it especially suitable for small and medium-sized fertilizer production enterprises.
Although disc granulators have capacity limitations in large-scale production, their excellent particle quality, flexible adjustment performance, and low investment costs make them ideal choices for granulation processes in small and medium-sized fertilizer plants. Through precise control of various parameters, disc granulators can stably produce high-quality fertilizer particles that meet various agricultural needs.
Integrating Disc Granulation into Modern Fertilizer Manufacturing
The disc granulator represents a crucial component in modern npk fertilizer production line configurations, offering unique advantages for specific production requirements. While the disc granulator machine excels in producing spherical, uniform particles through its unique fertilizer granulation mechanism, it operates alongside other technologies in complete manufacturing systems. The npk fertilizer manufacturing process often integrates multiple approaches, including npk blending machine operations for physical mixing and more advanced npk granulation machine technology for chemical granulation.
In comprehensive npk production process setups, the disc granulator typically follows initial material preparation using fertilizer mixer machine equipment. For operations focusing on manufacturing of npk fertilizer through blending rather than chemical granulation, npk bulk blending machine and bulk blending fertilizer machine units provide alternative solutions. The selection between these technologies depends on specific product requirements, with the npk fertilizer granulator machine offering chemical bonding while blending equipment provides physical mixture options.
Modern npk manufacturing continues to evolve, with the npk fertilizer production process incorporating increasingly sophisticated control systems. From basic npk fertilizer machine units to complete automated lines, the industry benefits from diverse technological approaches. While some facilities integrate fermentation composting technology for organic fertilizer for specialized products, the fundamental npk granulation machine principles remain essential knowledge for optimizing fertilizer production across different scales and product types.
