Compared with chemical fertilizer, NPK compound fertilizer has higher nutrient content, fewer by-components and better physical properties, which plays an important role in improving crop yield and quality. Compound fertilizer refers to any two kinds of fertilizer containing at least three components of nitrogen, phosphorus and potassium. Compared with basic fertilizer, its production technology is more complex, and fertilizer production is gradually becoming more specialized and diversified. Special compound fertilizer has been welcomed by more and more people. It plays an important role in improving crop yield and quality.
There are many kinds of equipments and processes for NPK compound fertilizer production, which are mainly based on the batching system and some actual conditions.
Rotary drum granulation production line is the most common equipment for NPK compound fertilizer processing. Compound fertilizer after processing has long efficiency and nutrient loss is not easy. The drum granulation NPK compound fertilizer production process is described below.
NPK compound fertilizer is produced by drum granulation, which makes the powdery basic fertilizer roll continuously, agglomerate into pellets, and make it compact and granular. In the drum granulation production line, bagged or bulk basic fertilizers should be crushed as much as possible into materials less than 20 mm before entering the granulation system. We crush them into powder by chain crusher.
These basic fertilizers are lifted to hoppers by bucket elevator, and then precisely proportioned by automatic proportioning system. Each batch of materials is proportionally and continuously sent to chain crusher by weighing belt machine for crushing. The material is crushed to a certain degree of fineness and sent to the drum granulator by the conveyor. A small amount of water or steam is added to the drum granulator to granulate the material.
The wet particles conveyed from the granulator are fed into the drum dryer by belt conveyor, and the heat supplied by the hot blast stove and wet materials are flowed into the dryer in a downstream way. There are induced fans on the rotary drum granulation production line to guide the wind direction. The import temperature of dryer depends on the formulation and material properties of NPK compound fertilizer, which is generally controlled at 150-200 ℃.
After drying and cooling, the material enters the sieving machine, and the unqualified particles and powders are returned to the granulating system. The qualified particles can be packed and stored.