Granulation mechanism of nitrophosphate based compound fertilizer

2020-01-31

In the industrial processing of compound fertilizer particles, the solid raw materials are usually mixed with liquid raw materials or with fertilizer slurry, and the proportion of dry solid raw materials is about 50-75%. The way of granulation is mainly through the rotation of the rotary drum granulator to make the material tumble and fall, and supply mechanical force to make the material powder contact with each other and impact to produce cohesion. When the material body reaches the liquid ratio required to make the solid particles agglomerate, it can be granulated. The liquid needed in granulation process is usually water, fertilizer slurry, liquid ammonia, sulfuric acid and phosphoric acid. In addition, in the granulation process, the solid raw materials will be partially dissolved into liquid phase due to the reaction heat generated by neutralization of acid ammonia, which is also helpful for granulation. The structure and shape of agglomerated granulated fertilizer particles are irregular, but most of the compound fertilizers are granulated in this way.

Production process of nitrophosphate based compound fertilizer

The first step of NPK fertilizer production line is to hydrolyze phosphate rock with nitric acid to produce fertilizer slurry, add sulfuric acid and phosphoric acid (when producing high phosphorus formula), then neutralize with liquid ammonia, and finally add potassium chloride to make fertilizer slurry with nitrogen, phosphorus and potassium components. It belongs to the whole fertilizer slurry process. After granulating, drying, screening, crushing, cooling, wrapping and other procedures, the fertilizer slurry is made into the finished fertilizer. The quality of the finished product is stable, the composition uniformity is good, the particle hardness is high and smooth, which is suitable for large-scale production of high nitrogen compound fertilizer.