In the production line of compound fertilizers, granulation is a key process of processing powdered or fine granular fertilizer raw materials into particles of a certain size and shape, in order to improve the physical and chemical properties of fertilizers, facilitate transportation, storage, and use. The common granulation methods mainly include the following:
1. Wet granulation
pan granulation
Add an appropriate amount of liquid (usually water or solution) to the mixed raw materials through a disc granulator, so that the raw materials aggregate into clusters under the action of a rotating disc.
Features: Simple operation, compact equipment structure, strong adaptability, especially suitable for small to medium-sized production lines.
extrusion granulation
The raw materials are fed into the perforated die of the roller extrusion granulator, and are extruded into strip-shaped or specific shaped particles through high pressure, and then cut into shape.
Advantages: High particle hardness, uniform size, suitable for high-density fertilizer preparation.
Efficient mixing granulation
Combining the process of mixing and granulation, the special structure inside the high-speed rotating mixer is utilized to promote the rapid aggregation and shaping of raw materials.
Widely applicable, capable of handling various materials and achieving continuous production.
2. Dry granulation
Friction granulation
By utilizing the friction between materials to bond them together, particles can be formed without the need for adding water.
Mainly used for humidity sensitive raw materials, avoiding subsequent drying steps and saving energy.
Agglomeration granulation
Through the action of mechanical force, the powders collide and bond with each other in an air suspended state, forming particles.
Suitable for materials with low viscosity or not easily hygroscopic.
3. spray granulation
Raw materials are dissolved or suspended in liquid, and granulation is completed while spray drying.
Especially suitable for processing raw materials that are highly soluble in water or have high volatile components.
Considerations when choosing granulation methods
Raw material properties: including chemical stability, flowability, particle size, etc.
Product requirements: required particle size, shape, strength, etc.
Cost effectiveness: including initial investment, operating costs, and maintenance expenses.
Environmental protection: whether harmful by-products are generated, such as dust emissions and wastewater treatment.
Different granulation technologies have their own advantages, and choosing the most suitable method for one’s own compound fertilizers production line requires a comprehensive evaluation of the above factors to meet the requirements of production efficiency, product quality, and economic benefits. In practical applications, many manufacturers also innovate and improve existing technologies based on specific needs to adapt to the increasingly diverse fertilizer market.
