BB fertilizer production lines rely on physical blending processes, primarily using granular raw materials. They have specific requirements regarding material morphology, hardness, and flowability. The main applicable types are conventional granular fertilizers, but functional additives can also be used. Some materials require pretreatment.

The core raw materials are various granular single-element fertilizers and compound fertilizers. Granular urea, granular potassium chloride, potassium sulfate, monoammonium phosphate, and diammonium phosphate are the most commonly used raw materials. These materials have uniform particle size, good flowability, and do not easily separate after mixing, resulting in optimal compatibility. In addition, granular ammonium chloride, calcium magnesium phosphate, potassium nitrate, magnesium sulfate, and other medium-element granular fertilizers can also be added as needed to formulate different nutrient compositions.

Functional additives are widely used, including granular humic acid, amino acids, seaweed extract, chelated trace elements, and silicon-calcium fertilizers, which can be directly blended to produce functional BB fertilizers. Some slow-release and controlled-release granular fertilizers can also be used to create long-acting blended fertilizers.

There are specific restrictions and precautions regarding the use of raw materials. Materials that are prone to chemical reactions must not be mixed. For example, mixing urea with nitrate nitrogen fertilizer or strong acid fertilizer with strong alkaline fertilizer is prone to moisture absorption, clumping, and nutrient loss. Direct addition of large quantities of powdered raw materials is not recommended, as it easily causes stratification of the finished product and increased dust. If powdered materials must be added, pre-granulation is recommended.

The moisture content of raw materials must be uniformly controlled between 8% and 12%. Excessive moisture will cause material adhesion, bridging in the silo, and uneven mixing. Simultaneously, the particle size should be as close as possible; excessive particle size differences will cause stratification during transportation and stacking, affecting nutrient uniformity.

Overall, this production line is compatible with most granular nitrogen, phosphorus, and potassium fertilizers and granular functional additives. Its flexible formulation adjustment is a key reason for its wide application range and high market penetration.