The double roller press granulator produciton technology relies on physical high-pressure molding. Particle hardness directly affects finished product quality, storage and transportation losses, and market reputation. To consistently improve particle hardness, a systematic optimization approach can be implemented from three aspects: raw materials, process, and equipment.

Controlling the moisture content of raw materials is crucial. Excessive moisture content leads to loose extrusion and soft particles. Generally, moisture content should be controlled at 8%–10%. If moisture content is too low, appropriate atomization humidification can be used to ensure the material has both fluidity and binding properties. The fineness of the raw materials should be uniform. Excessive coarseness can cause pressure dispersion and poor molding. A fineness of 80–100 mesh is recommended to increase extrusion density.

Properly matching material ratios enhances self-binding strength. High proportions of nitrogen and potassium fertilizers can lead to looseness; adding appropriate amounts of bentonite, calcium powder, humic acid, and other additives can enhance material binding. For easily loose materials, a small amount of safe and harmless binder can be added to significantly improve particle strength.

Optimizing the operating parameters of fertilizer production machines is a core approach. Increase the extrusion pressure appropriately, increasing the inter-roller pressure within the motor's load capacity to make the material denser. Ensure uniform and stable feeding, avoiding pressure fluctuations caused by inconsistent feeding. A screw feeder can be used to ensure continuous and uniform feeding.

Regularly maintain key components to ensure molding quality. Severe wear of the roller skin and die grooves will result in shallow molding and low density, requiring timely repair or replacement. Inspect bearings and the hydraulic system to ensure stable pressure, no pressure leakage, and no vibration.

Properly perform subsequent crushing and screening to avoid secondary loosening. Control the crushing speed to prevent over-crushing that causes particle cracking. Qualified particles should be screened directly, while unqualified material should be returned for re-extrusion.

Through these measures, particle density and hardness can be significantly improved, resulting in smooth, high-strength particles that are less prone to breakage, meeting the requirements for storage, transportation, and application.