The mixed fertilizer production line is a complete equipment system for customized nutrient ratio fertilizers by accurately mixing various granular base fertilizers (such as urea, monoammonium phosphate, potassium chloride, potassium sulfate, trace element fertilizers, etc.) according to the formula ratio. Its core is physical mixing (without chemical reactions), with a focus on ingredient accuracy and mixing uniformity. The following are typical components and core equipment of a mixed fertilizer production line:

　　

　　Raw material pretreatment and storage system

　　

　　The raw materials for mixed fertilizers are mostly granular solids (usually with a particle size of 2-4mm). Pre treatment requires removing impurities, crushing lumps, and ensuring the flowability and uniformity of the raw materials.

　　

　　Raw material storage equipment

　　

　　Raw material warehouse (hopper): designed separately according to the type of raw material, usually with a steel cone bottom structure (for easy unloading), and the capacity is determined based on daily production capacity and raw material supply cycle (such as 5-20 tons/warehouse).

　　

　　Function: Store single raw materials such as urea, monoammonium phosphate, potassium fertilizer, and trace elements separately to avoid cross contamination.

　　

　　Auxiliary device: Some silos are equipped with vibration arch breaking devices (pneumatic or electric vibrators) or mixing anti arch mechanisms to prevent raw materials from being blocked due to moisture absorption and agglomeration (especially urea and ammonium phosphate are prone to moisture absorption).

　　

　　Raw material lifting and transportation: Raw materials are transported from the storage area to the pre-treatment or batching station through bucket elevators or screw conveyors.

　　

　　Preprocessing equipment

　　

　　Screening machine: using a vibrating screen (such as a linear vibrating screen), the mesh size is designed according to the particle size of the raw material (usually 2-5mm), to remove large lumps, impurities (such as stones, plastic bags) or fine powder from the raw material (to avoid layering after mixing).

　　

　　Crusher (optional): For slightly agglomerated raw materials (such as ammonium phosphate), the agglomerates are crushed to qualified particle size using a toothed roller crusher or hammer crusher, and then returned to the screening machine for secondary screening.

　　

　　 Measurement and batching system

　　

　　Accurately weighing each raw material according to the formula ratio is the core link to ensure that the nutrient content of the mixed fertilizer meets the standard.

　　

　　 Measuring equipment

　　

　　Weight loss feeder: suitable for small and medium-sized raw materials (such as urea and potassium chloride), calculates the discharge amount in real time through the weight change of the silo, with an accuracy of ± 0.2%, and supports continuous and stable feeding.

　　

　　Belt scale/spiral scale: Used in conjunction with belt conveyors or spiral conveyors, it calculates instantaneous flow rate through weighing sensors and speed sensors with an accuracy of ± 0.5%. It is suitable for large particles or materials with good flowability.

　　

　　Bucket scale: an intermittent measuring device that unloads materials in one go after weighing through a hopper. It is suitable for small proportion raw materials such as trace elements (with an addition amount ≤ 5%), avoiding the accumulation of continuous measurement errors.

　　

　　Ingredient control system

　　

　　PLC automatic control system: integrates signals from various measuring devices, automatically adjusts the feeding speed of each raw material according to preset formulas (such as N: P ₂ O ₅: K ₂ O=15:15:15), and achieves dynamic proportioning control.

　　

　　Human Machine Interaction Interface (HMI): Operators can modify formulas, monitor the flow of various raw materials, view production data (such as cumulative output and ingredient errors), and support formula storage (dozens of commonly used formulas can be preset) through the touch screen.

　　

　　 Hybrid system

　　

　　Mixing multiple measured raw materials evenly to ensure consistent distribution of nutrients in the finished product is the "heart" of the production line.

　　

　　Core equipment: mixer

　　

　　Dual axis paddle mixer: the most commonly used equipment, which drives the paddle blades to push, shear, and mix materials by convection through two reverse rotating shafts. The mixing uniformity is high (coefficient of variation CV ≤ 5%), the mixing time is short (30-60 seconds/batch), and the residual amount is low (≤ 0.1%).

　　

　　Features: Suitable for mixing raw materials with similar particle sizes, with a low damage rate (≤ 1%) to prevent particle breakage and subsequent delamination.

　　

　　Horizontal spiral belt mixer: The material is rolled and mixed up and down by the spiral pushing of the inner and outer spiral belts. It is suitable for raw materials with poor fluidity or containing a small amount of powder. The mixing uniformity is slightly lower than that of the double axis propeller blade machine (CV ≤ 7%), but the structure is simple and easy to maintain.