During the organic fertilizer production process, granule shape directly affects product appearance, transportation performance, and market competitiveness. Many manufacturers frequently face problems such as irregular granules and rough surfaces. These issues can be effectively resolved by precisely addressing three core aspects: materials, equipment, and process, thereby upgrading granule quality.
Material pretreatment is fundamental. Uneven moisture content in raw materials can easily lead to granule clumping or loosening. The moisture content needs to be precisely controlled between 12% and 18%, using a spray humidification system for even water distribution, followed by thorough turning and mixing after composting. If there are significant differences in raw material particle size, pre-screening should be performed to ensure particle size is within the range of 1-5mm, preventing uneven mixing of coarse and fine particles from affecting granulation. For raw materials with high fiber content, such as straw and cow dung, pretreatment with a double-shaft mixer is necessary. If needed, 3%-8% bentonite or other binders should be added to improve material viscosity and granulation stability.
Equipment parameter optimization is crucial. The rotary drum granulator's inclination should be adjusted to 2°-3° to ensure sufficient material rolling; the rotation speed should be matched to the material characteristics, controlling fine powder materials at 8-12 r/min and coarse particles at 12-18 r/min, with dynamic optimization using variable frequency speed control. If wear on the inner wall of the equipment causes poor material rolling, the rubber or stainless steel lining should be replaced promptly, and residual clumps should be cleaned regularly. The ball shaping machine, as a core auxiliary equipment for improving granule roundness, is recommended for use in conjunction with the granulator: for granules produced by disc granulation, the centrifugal force and friction of the ball shaping machine cause the granules to collide and rub against each other, quickly removing sharp edges and forming smooth, round granules; for irregular granules produced by rotary drum granulation, the ball shaping machine can further optimize the appearance, increasing the granule roundness compliance rate to over 95%. When using the ball shaping machine, the rotation speed should be controlled at 20-30 r/min, and the feed rate should be adjusted to ensure sufficient polishing time for the granules inside the machine. The smoothness of the inner wall of the drum should also be checked regularly to prevent wear from affecting the polishing effect.
Process control requires meticulous management. A screw feeder is used to ensure uniform feeding and prevent localized accumulation; the granulation temperature is controlled at 40-60℃, and a low-temperature, high-airflow mode is used during the drying stage to prevent uneven shrinkage and deformation of the granules. A standardized operating procedure is established, and the optimal parameters are determined through small-scale trials. Sufficient recycled material is also ensured, allowing 1-2mm small particles to act as the core for granulation, effectively preventing flat and deformed particles.
In summary, the problem of non-spherical granules requires comprehensive investigation and treatment. In the production of organic fertilizers, through the synergistic optimization of raw material homogenization, precise equipment adjustment, and dynamic process control, both the sphericity of the granules and the product's market competitiveness can be improved, leading to increased production efficiency.
