The industrial production of NPK compound fertilizer follows a fixed and rigorous standardized process. Each step is interconnected and directly determines the fertilizer's nutrient uniformity, granule quality, and storage stability. The standardized NPK fertilizer production sequence is: raw material pretreatment → precise proportioning and mixing → granulation and molding → drying and cooling → screening and coating → quality inspection and packaging. This orderly process is the core foundation for ensuring the finished fertilizer meets standards.

Raw material pretreatment is the first step in production. Before production, the purity and quality of core raw materials such as urea, monoammonium phosphate, and potassium chloride must be verified, and impurities and lumps must be removed. Subsequently, the raw materials are pulverized to a standard fineness of 80 to 100 mesh using a pulverizer, and pre-drying is performed simultaneously to control the initial moisture content of the raw materials, preventing impurities and coarse particles from affecting subsequent mixing and granulation effects, thus laying a solid foundation for subsequent processes.
The second step is precise proportioning and homogeneous mixing. Based on national standard formulas such as 15-15-15 and 17-17-17, various raw materials are precisely metered using an automated batching system, strictly controlling proportioning errors. The metered raw materials are then thoroughly mixed in a mixing device to ensure uniform distribution of nitrogen, phosphorus, and potassium nutrients, preventing localized nutrient imbalances and avoiding the process contraindication of high-temperature reaction between ammonium raw materials and potassium chloride.
Granulation is the core process. The uniformly mixed material is fed into granulation equipment, primarily using disc,rotary drum, or extrusion granulation processes. The appropriate process is selected based on product positioning, and environmentally friendly binders are added as needed to agglomerate loose materials into regular granules, initially forming the fertilizer structure and controlling granulation rate and granule regularity.
After molding, the fertilizer undergoes drying and cooling. High-temperature drying reduces the fertilizer moisture content to below 2%, completely removing moisture and preventing clumping and deterioration. After high-temperature drying, the fertilizer is rapidly cooled using air-cooling equipment to stabilize the granule structure, improve granule strength, and prevent pulverization and breakage caused by direct stacking of high-temperature materials.
Finally, the process involves screening, coating, quality inspection, and packaging. Screening equipment selects uniformly sized, qualified granules, removing powder and oversized particles. Qualified granules undergo anti-caking coating treatment to improve fertilizer storage performance. After the finished product meets standards for nutrient content, granule strength, and moisture content, it is automatically packaged, completing the entire production process.
This standardized NPK fertilizer production sequence is rigorously controlled at every stage, effectively ensuring stable quality and balanced nutrients, meeting agricultural fertilizer application standards.