2026/07/08
Raw Material Selection Criteria:
The key to BB fertilizer production lies in ensuring that the particle size distribution and specific gravity of the raw materials are similar. Particle size differences should be controlled within ±0.5 mm (e.g., urea 2–4 mm, diammonium phosphate 2–4 mm, potassium chloride 2–4 mm), and the difference in specific gravity should not exceed 0.3 g/cm³. If granular organic fertilizer materials are used, they must be precisely screened beforehand using a fertilizer screening machine to ensure consistent particle size ranges across all components. Materials with differing specific gravities are prone to stratification and segregation during mixing, conveying, and packaging, resulting in uneven nutrient content.
Mixing Process Control:
A dedicated BB fertilizer mixer is recommended; these typically feature a rotating drum or ribbon-style structure, offer short mixing times (generally 2–3 minutes), and operate with a loading factor of 60%–70%. Excessive mixing time increases inter-particle friction, leading to a higher rate of pulverization. The mixer interior should be fitted with a rubber lining to minimize granule breakage. After each batch is mixed, the unit must be completely emptied to prevent residual material from contaminating the next batch and altering the formula.
For formulas containing trace elements, a "stepwise premixing" process should be adopted: first, premix the trace elements with a small amount of large-particle raw material in a small mixer, then introduce this mixture into the main mixer to ensure uniform distribution of the trace components.
Packaging and Storage:
BB fertilizer should be packaged promptly after mixing to avoid prolonged storage in hoppers (recommended limit: ≤2 hours), which could lead to vibration-induced segregation. Precise metering should be performed using an automatic packaging scale prior to sealing and palletizing via a bag-sewing machine and conveyor belt. Composite bags with inner liners are recommended, as they offer both moisture resistance and tear strength. When storing finished products, BB fertilizers with different formulations must be stacked in designated zones and clearly labeled to prevent mix-ups. If significant color stratification or excessive granule breakage (>5%) is observed within the packaging, the mixing duration or the drop height during conveying (which should be kept at ≤1.5 meters) must be investigated, and production process parameters adjusted accordingly. Additionally, it is recommended to sample and test the nutrient content of each batch (ensuring the deviation between labeled and measured N-P-K values is ≤0.5%) to guarantee a 100% pass rate for outgoing products.