What are the production processes for bulk blended fertilizers?

Blended fertilizers, also known as BB fertilizers, are compound fertilizers made by physically mixing various granular basic fertilizers such as nitrogen, phosphorus, and potassium according to soil testing and crop requirements. Their production process is simple and efficient, with flexible formulations that can quickly adapt to the fertilization needs of different regions and crops, making them an important category of fertilizers in modern agriculture. The complete production process for blended fertilizers mainly includes five core stages: raw material pretreatment, precise ingredient proportioning, uniform mixing, finished product processing, and packaging and warehousing.

Raw material pretreatment is the foundation of production. Before production, basic raw materials such as urea, diammonium phosphate, and potassium chloride must be strictly screened, controlling the particle diameter to 2-4 mm to ensure uniform particle size and avoid stratification due to particle size differences. Simultaneously, the moisture content of the raw materials must be tested and controlled below 1% to prevent moisture absorption and clumping. Raw materials must be stored separately in dry, sealed silos. Depending on the formulation requirements, appropriate amounts of micronutrients such as boron, zinc, and iron, as well as anti-caking agents, can be added to lay the foundation for stable subsequent production.

Precise ingredient proportioning is crucial for ensuring nutrient content meets standards. Modern bulk blending fertilizer production lines employ automatic batching systems, accurately weighing various raw materials according to the formula ratio, with measurement errors controlled within ±0.5%. The system can store multiple formulas, quickly switching between them to meet different order requirements, avoiding errors and contamination from manual batching. After batching, the raw materials are evenly fed into the mixer via lifting equipment, achieving continuous and standardized feeding.

Uniform mixing is the core process step of the BB fertilizer production line. After the materials enter the BB fertilizer blender, they are fully integrated under stirring, with a mixing time typically no less than 3 minutes, ensuring that the coefficient of variation in nutrient uniformity is ≤5%. This step effectively avoids localized excessively high or low nutrient levels, ensuring balanced nutrient content in every fertilizer granule. The entire mixing process is enclosed, reducing dust leakage and meeting environmental protection production requirements.

Finished product processing and packaging are the final steps. The properly mixed fertilizer is conveyed to the finished product warehouse via belt conveyor. Some production lines add a secondary screening to remove small amounts of lumps and impurities, improving the product's appearance and flowability. The product then enters an automated packaging system, completing processes such as quantitative bagging, sealing, and coding. After quality inspection to ensure nutrient content, uniformity, and moisture content meet standards, the finished product is stored for sale.

Overall, the production process of bulk blended fertilizers primarily relies on physical mixing, without high-temperature chemical reactions. This offers advantages such as low investment, low energy consumption, flexible formula adjustments, and high production efficiency. By strictly controlling each process, ensuring proper raw material selection, precise ingredient proportioning, and uniform mixing, high-quality blended fertilizers with balanced nutrients and stable quality can be produced, contributing to scientific fertilization and improved agricultural quality and efficiency.