How to Improve the Hardness of Pelletize Produced by Organic Fertilizer Ball Shaping Machines?
Adjusting process parameters during the forming process directly affects the initial density. The core is precisely controlling the material moisture content, typically maintaining it within the optimal plastic range of 25% to 35%. Too low a moisture content prevents bonding, while too high a moisture content results in soft, mushy pellets. Inside the rounding machine, appropriately increasing the cylinder speed increases the centrifugal extrusion force. Combined with adjusting the baffles to extend the material residence time, this allows the "raw pellets" to undergo more tossing and rolling, effectively expelling internal air and making the structure more compact.
However, the rounding machine only produces "wet blanks," and the final hardness largely depends on subsequent drying and aging. High-temperature rapid drying is strictly prohibited, as it will cause the surface to harden and form a crust while the interior remains soft and moist, resulting in a "sugar core" defect. A low-temperature, slow drying process should be used to allow moisture to evaporate evenly from the inside out, enabling the binder to fully solidify. The subsequent 24 to 48 hours of static aging after drying is also crucial. This process balances internal stress and residual moisture, typically resulting in a natural hardness increase of over 15%. In summary, improving hardness is a delicate task that requires coordinating the plasticity of the formulation, mechanical force, and drying kinetics.

