What is the NPK fertilizer production process?

NPK compound fertilizer is a high-efficiency fertilizer that integrates three core nutrients: nitrogen, phosphorus, and potassium, suitable for the growth needs of various crops. The NPK fertilizer production process is rigorous and standardized, using multiple refined processes to process single raw materials into granular fertilizers with balanced nutrients and stable properties, ensuring both precise proportioning and finished product quality throughout the process.

The first step in production is raw material pretreatment. Urea and ammonium chloride are commonly used as nitrogen sources, monoammonium phosphate and diammonium phosphate as phosphorus sources, and potassium chloride as a potassium source. All raw materials undergo dual screening by both manual labor and equipment to remove impurities and lumps, and are then ground into a fine powder of 80 to 100 mesh. This step prevents clumping and uneven mixing, laying a solid foundation for subsequent precise proportioning and uniform blending, while strictly controlling the moisture content of the raw materials to ensure production stability.

The second step is precise proportioning and thorough mixing. Workers set formulas according to the fertilization needs of different crops, and relying on an automated batching system, accurately weigh the nitrogen, phosphorus, and potassium raw materials, as well as trace elements. After the proportions are finalized, the raw materials are fed into a specialized mixer for thorough mixing and uniform blending. This ensures consistent nutrient content in each component, preventing nutrient imbalances at the source and guaranteeing balanced fertilization results.

Granulation is the core process. The uniformly mixed powder is fed into a disc or rotary drum granulator. Humidity is increased by spraying water or steam, causing the materials to adhere and agglomerate during the rolling motion, gradually forming regular granules. The granulation process is stable, ensuring uniform granule size and compact structure, avoiding hollow or broken granules, and improving fertilizer quality.

The formed granules undergo drying, cooling, and screening. The wet granules are fed into a drum dryer and dried at a constant temperature of 120-180℃, reducing the moisture content to below 2% to prevent clumping. The dried, high-temperature granules are cooled to room temperature by an air-cooling device and then screened by a vibrating screen to remove oversized or undersized granules, retaining only uniformly sized finished granules. Unqualified granules can be crushed and reused.

Finally, the fertilizer undergoes coating, quality inspection, and packaging processes. Qualified granules are coated to form a protective layer, effectively preventing clumping, nutrient loss, and extending the fertilizer's shelf life. After coating, samples are tested for nutrient content, granule strength, and other indicators. Once the standards are met, the granules are automatically packaged and stored, ultimately becoming high-quality NPK compound fertilizer ready for market.