Rotary Drum Granulator:How Are Fertilizer Granules Born?

Have you ever wondered how those round, uniform fertilizer granules are transformed from powder-like raw materials? On the fertilizer production line, there is one piece of equipment specifically responsible for this magical powder-to-granule transformation: the rotary drum granulator. If the double roller press granulator represents the king of dry granulation, then the rotary drum granulator reigns supreme in wet granulation. By spraying steam, water, or binders, it causes powdered materials to gradually agglomerate into balls as they tumble, eventually becoming full, hard fertilizer granules after drying and cooling. How the Rotary Drum Granulator Works The structure of a rotary drum granulator may appear simple, but it embodies a sophisticated granulation mechanism: Drum Rotation: A slightly inclined cylinder rotates slowly, driven by a power unit. Material enters from the higher end and continuously tumbles inside the drum. Agglomeration: Nozzles spray steam or binder solution onto the material surface, wetting the fine powder particles. These particles then stick together during rolling and gradually grow into granules. Compaction: The material not only rolls but also compresses under its own weight, making the granules denser and more rounded. Self-Cleaning: The inner wall is equipped with rubber liners or scrapers to prevent material adhesion, ensuring continuous and stable operation. As the drum tilts and rotates, the growing granules gradually move toward the lower end and finally discharge from the outlet, entering the next process step. Core Advantages of Rotary Drum Granulators Why has the rotary drum granulator become standard equipment in compound fertilizer production lines? It offers numerous advantages that are difficult to replace: Large Processing Capacity: Single-unit output can range from several tons to tens of tons per hour, making it suitable for large-scale industrial production. High Granulation Rate: Under reasonable formulation and operating conditions, granulation rates can reach 70 to 90 percent, resulting in less return material and higher efficiency. Good Granule Strength: Granules formed through rolling and compaction have a dense structure, high strength, and resist powdering during handling and storage. Wide Application Range: Suitable for producing compound fertilizers, organic-inorganic compound fertilizers, specialty fertilizers, and more. Operational Flexibility: Parameters such as rotation speed, inclination angle, and spray volume can be adjusted according to raw material characteristics and product requirements. Core Role in the Production Line In a complete compound fertilizer production line, the rotary drum granulator occupies a central position, connecting upstream and downstream processes: Upstream Equipment: Includes chain crusher, mixers, and dosing systems that accurately proportion and thoroughly mix various raw materials. Granulation Process: The mixed powder enters the rotary drum granulator and agglomerates into granules under the action of steam and binders. Downstream Equipment: Wet granules enter the dryer to remove moisture, then pass through a cooler for temperature reduction, and finally through a screener for classification. Qualified granules proceed to packaging, while unqualified material returns to the granulator for reprocessing. The entire production line operates as an integrated system, and the rotary drum granulator is the key component that transforms powder into finished product. From Fertilizer Plants to Farmlands Rotary drum granulators are widely used across the fertilizer industry: Large Compound Fertilizer Plants: They serve as the core granulation equipment in production lines with annual capacities ranging from tens of thousands to hundreds of thousands of tons. Organic-Inorganic Compound Fertilizer Plants: They effectively combine organic materials with inorganic nutrients to produce functional fertilizers. Specialty Fertilizer Production: They enable custom formulation according to specific crop and soil requirements. Whether in modern industrial parks or fertilizer workshops near agricultural areas, rotary drum granulators work steadily, transforming nutrients into granules that eventually nourish crops and contribute to harvests. Every Granule Tells a Story From powder to granule, from raw material to finished product, the rotary drum granulator performs the most transformative step in fertilizer production through its rotating and tumbling action. Behind every round, uniform fertilizer granule lies the engineering design of the equipment, the careful adjustments of operators, and the seamless coordination of the entire production line.