Ball Shaping Machine

The spheronizer is a piece of equipment used in organic fertilizer production to round and polish cylindrical granules—which possess good plasticity—after they emerge from granulators such as extrusion granulators. Representing an improvement over older organic fertilizer machinery, this new type of spheronizer enables continuous feeding and discharging, thereby significantly boosting production efficiency. It is a crucial piece of auxiliary equipment for enhancing the quality of commercial organic fertilizer. Operating on the principle of high-speed rotation and material-on-material friction, the machine rapidly smooths away sharp edges and corners, resulting in granules that are round, plump, and uniform; this fundamentally resolves production issues related to deformed or irregular-looking granules.

Component Composition and Functional Zoning

From a production process perspective, the spheronizer can be categorized into the following functional units:

(I) Feeding unit: Comprising a feed hopper and a conveying device, this unit uniformly feeds granulated semi-finished pellets into the spheronizer.

(II) Spheronization and shaping unit: This is the core component of the equipment, consisting of multi-stage spheronization cylinders or inverted conical rotating discs. Common configurations include single-stage, dual-stage, and three-stage series arrangements. Cylinder diameters typically range from 800 mm to over 1,200 mm.

(III) Power transmission unit: Comprising the drive motor, pulleys, and transmission system. The main motor typically ranges from 5.5 kW to 15 kW.

(IV) Liquid spraying auxiliary unit: Includes atomizing nozzles used to facilitate the healing of the pellet surface during the spheronization process.

(V) Discharge and screening unit: Includes the discharge outlet and grading screens used to separate and collect compliant pellets.

(VI) Frame and cleaning unit: Includes the machine frame and internal scrapers. The scrapers prevent wet material from temporarily adhering to the walls.

Production Line Roles and Process Flow

The spheronizer serves as a pivotal post-processing unit in organic and compound fertilizer production lines, bridging the gap between the granulation and drying stages. The complete process flow is as follows: raw material pretreatment → granulation → spheronization/shaping → drying → cooling → screening → coating → packaging.

The spheronizer is compatible with virtually all upstream granulation technologies; it can be integrated into the line to perform post-shaping after flat-die, ring-die, double-roller extrusion, disc, or rotary drum granulation. Typically positioned between the granulator and the dryer—or upstream of the screening and material recycling stage—the equipment can operate in conjunction with one or multiple granulators. This setup resolves the drawbacks associated with the traditional "one-to-one" configuration (where each granulator required its own spheronizer), such as process complexity, high equipment investment costs, and inconsistent product quality across multiple units.

Description of the Circular Spinning Process and Stages

The spheronization process of the spheronizer can be divided into the following stages:

Feed distribution stage: Irregular granules from the granulation process are conveyed into the spheronizer hopper and distributed evenly onto the center of a high-speed rotating polishing disc.

Centrifugal projection stage: Driven by the transmission system, the polishing disc rotates at high speed, generating strong centrifugal force that propels the granules toward the inner wall of the spheronization chamber.

Rolling and smoothing stage: Under the combined action of centrifugal force, friction, and gravity, the granules continuously roll, collide, and rub against the chamber wall, gradually smoothing out their sharp edges. Driven by centrifugal force, the cylindrical material moves in a twisting, reciprocating motion along the edge of the polishing disc and the inner wall of the chamber.

Surface densification stage: Assisted by a liquid spraying system, the granule surfaces become smooth and dense, resulting in well-rounded, spherical particles.

Multi-stage fine spheronization stage: When the material accumulation height exceeds the overflow port, it automatically advances to the next stage for further fine spheronization. After undergoing the same motion across multiple spheronization discs, the cylindrical material gradually transforms into uniform, glossy, spherical particles.

Screening and discharge stage: The formed granules are sorted via a grading screen, and the qualified spherical particles are discharged through the final outlet. A very small number of oversized agglomerates can be screened out and returned for re-granulation, effectively eliminating waste material.

Pre-granulation and Material Requirements

The spheronizer imposes specific requirements on the feed granules. Initial strength: The feed granules must possess sufficient plasticity to maintain their structural integrity during the spheronization process. Moisture content: Ideally, the moisture content of the feed material should be maintained between 20% and 35%; excessive moisture causes sticking to the chamber walls, while insufficient moisture makes rounding difficult and increases the risk of powdering. If necessary, a small amount of atomized water can be sprayed at the inlet to facilitate surface healing. Granule morphology: The spheronizer processes cylindrical or irregularly shaped semi-finished granules produced by a granulator; it cannot replace the granulator for the initial formation of the granules.

Operational Guidelines and Key Control Points

Standardized operation of the spheronizer is crucial for ensuring product quality and equipment longevity:

Pre-start preparation: Ensure the interior is free of debris to prevent machine damage or compromised spheronization quality. Check that all bolts are tightened and transmission components are adequately lubricated. Verify that the liquid spraying system is unobstructed.

Operational control: Flexibly adjust the rotation speed (500–1500 rpm) based on material characteristics using the variable frequency drive to precisely control granule roundness and density. Monitor motor current stability and observe the granule formation quality. Strictly prohibit inserting hands or foreign objects into the equipment during operation.

Post-shutdown handling: Empty residual material after each shift to prevent crusting. Regularly clean components prone to material buildup—such as the spheronization disc and spray nozzles—to prevent clogging or corrosion.