NPK compound fertilizer is a high-efficiency fertilizer rich in the three core nutrients of nitrogen, phosphorus, and potassium, suitable for the growth needs of various crops. Its industrial production process is rigorous and standardized, achieving precise raw material ratios and uniform nutrient integration through multiple refined processes, ultimately producing granular fertilizer with stable quality and high utilization rate. The complete NPK fertilizer production process consists of six core steps.

The first step is raw material pretreatment. Commonly used basic raw materials such as urea, monoammonium phosphate, and potassium chloride are prone to caking during storage. They need to be crushed and ground into a fine powder of 80 to 100 mesh using a specialized crusher. Simultaneously, impurities are removed, and the moisture content of the raw materials is controlled to avoid affecting subsequent mixing and granulation, laying a solid foundation for standardized production.
The second step is precise ingredient proportioning and mixing. The proportions are set according to the nutrient requirements of different crops and soils. An automatic batching system precisely measures various raw materials, with proportioning errors strictly controlled within the standard range. The metered raw materials are fed into a mixer and thoroughly mixed for 10 to 15 minutes to ensure even distribution of nitrogen, phosphorus, and potassium nutrients and prevent localized nutrient imbalances.
The third step is core granulation. The evenly mixed powder is fed into a rotary drum granulator, where it is kneaded and clumped together by rotation, with the aid of appropriate steam or environmentally friendly binders, gradually forming initial granules of 2 to 5 millimeters. This process determines the fertilizer granule formation rate and is crucial for ensuring the fertilizer's appearance and application effectiveness.
The fourth step is drying and cooling. Freshly formed wet granules have a high moisture content, are soft, and easily clump together. They need to be sent to a drum dryer for constant-temperature drying to reduce the moisture content to below 2% and increase granule hardness. After high-temperature drying, the granules are cooled to stabilize their structure and prevent clumping and breakage during subsequent storage and transportation.
The fifth step is screening and coating. The cooled granules are graded by a vibrating screen to select uniformly sized qualified granules. Unqualified granules that are too large or too small are re-crushed and recycled. Qualified granules can be coated with an anti-caking coating to extend shelf life and improve slow-release performance.
Finally, quality inspection and packaging are completed. Finished fertilizers undergo testing for nutrient content, granule strength, and moisture content. Once qualified, they are quantitatively packaged and labeled using automated packaging equipment before being stored, completing the entire production process. The high degree of automation ensures balanced nutrients and stable quality in NPK compound fertilizers, meeting the needs of large-scale fertilization in modern agriculture.