Double roller press granulators are efficient and energy-saving equipment widely used in producing granular fertilizers like organic fertilizer, compound fertilizer, and bio-fertilizer. However, not all raw materials are directly suitable for extrusion granulation. The physical and chemical properties of the material directly affect the granulation results.
Physical Property Requirements
1.Appropriate Particle Size
Raw materials must be crushed, generally to 80-200 mesh (0.074-0.2mm). Particles that are too coarse make forming difficult, while particles too fine can affect flowability and cause the material to stick to the rollers.
2.Moderate Moisture Content
Excessive moisture (>15%) causes material to stick to the rollers and affects demolding. Insufficient moisture (<8%) makes forming difficult, and the granules become brittle. The optimal moisture range is usually 8%-12%, though this may vary based on material characteristics.
3.Good Plasticity
Materials need some stickiness and plasticity (like humic acid, composted manure, bentonite) to help improve granule formation rate and hardness.
Chemical Property Requirements
1.Moderate Organic Matter Content
For organic fertilizer materials (like compost, humic acid), an organic matter content of 30%-70% is recommended. Too high can lead to loose granules; too low affects fertilizer efficiency.
2.No Corrosive Components
Strong acids, strong alkalis, or high-salt substances should be avoided in the raw materials to prevent equipment corrosion or harm to crops.
3.No Hard Impurities
Hard objects like stones or metal fragments can damage the double roller press granulator die. Screening or magnetic separation is needed before granulation.
Double roller press granulators have strict requirements for raw material particle size, moisture, and binding properties. Selecting suitable materials and optimizing process parameters are essential for producing high-strength, qualified granular fertilizer.