The rotary drum granulator is a core piece of equipment for producing compound fertilizers, organic fertilizers, and NPK fertilizers. It transforms powdered raw materials into uniform granules through physical tumbling and chemical binding.

1.Raw Material Preparation
Powdered raw materials are crushed and screened to ensure uniform particle size. This improves granulation efficiency and granule strength. Nutrient ratios (nitrogen, phosphorus, potassium, etc.) are adjusted according to the formula to ensure balanced nutrition in the final product.
2.Mixing and Moistening
Materials enter the rotary drum granulator, where liquid (water, steam, or a binder) is sprayed in. This moistens the material surface, promoting granule formation. Liquid spraying must be precisely controlled—too much causes over-wetting and clumping, while too little reduces granulation rates.
3.Tumbling and Granule Formation
The drum rotates at a suitable speed (typically 10-20 rpm). Material rolls and agglomerates under centrifugal force and friction, forming initial granules. Internal baffles may be installed to improve mixing and granule uniformity.
4.Drying and Screening
Newly formed granules move to a dryer to remove excess moisture, improving hardness and storage stability. After vibrating screening, qualified granules proceed to coating or packaging. Fine powder is recycled back to the granulator, reducing waste.

Factors Affecting Granulation Efficiency
1.Drum Rotation Speed: Low speed slows granule formation; high speed risks breaking granules.
2.Liquid Spray Method: Atomized spray ensures even distribution and higher granulation rates.
3.Raw Material Ratio: Proper nutrient balance and binder selection impact granule strength and solubility.
4.Temperature Control: Moderate heating speeds up moisture removal and drying efficiency.

By adjusting parameters like rotation speed, liquid spray volume, and material ratios, the rotary drum granulator process can be optimized to produce uniform, strong granules with excellent slow-release properties.