In modern agriculture, sulfur-coated urea is gaining increasing popularity among global growers as an efficient coated slow-release fertilizer. This innovative fertilizer achieves precise nutrient release through special coating technology, effectively improving fertilizer utilization efficiency and reducing environmental pollution.
Precision Production Process
The production of sulfur-coated urea begins with strictly selected raw materials. The core material is granular urea with diameters of 1.00-5.60 mm, requiring a particle size qualification rate of over 90%. High-purity sulfur (≥99.8%) serves as the main coating material, combined with sealants and conditioners to form a complete coating system.
The production process starts by preheating urea particles to 63°C, then transferring them into a sulfur-coating drum at 77°C. In this crucial step, sulfur is heated to around 140°C to melt, then atomized and evenly sprayed onto the rolling urea particles under 7 MPa pressure. This process requires precise control of temperature and time to ensure the formation of a uniform sulfur coating approximately 50 microns thick.
Sophisticated Multi-layer Coating Design
The pure sulfur coating contains micropores that could lead to rapid nitrogen release. Therefore, the production process includes a sealant coating procedure. Using a mixture of polyethylene and heavy oil as sealant effectively closes the pores in the sulfur coating, preventing explosive nitrogen release. Subsequent cooling reduces particle temperature below 40°C, creating conditions for further processing.
Finally, diatomaceous earth and other conditioners are used for outer layer coating. This design not only improves particle flowability but also prevents particles from floating on water surfaces, ensuring the fertilizer sinks properly into the soil to function effectively.
Significant Agronomic Advantages
The slow-release characteristics of sulfur-coated urea make it outstanding in agricultural production. Typical sulfur-coated urea products contain 35% nitrogen and 18% sulfur, providing not only the main nutrient elements required by crops but also supplementing important secondary elements. Its unique release profile shows: 35% nitrogen release on the first day, with cumulative release reaching 55% within seven days. This gradual release pattern better matches crops’ nutrient absorption patterns.
In practical applications, sulfur-coated urea significantly reduces fertilization frequency and labor costs. Meanwhile, by improving nutrient utilization efficiency, it reduces nitrogen leaching and greenhouse gas emissions, making it more environmentally friendly. Taking a factory with an annual production capacity of 50,000 tons as an example, it can process 150 tons of urea raw materials daily, producing approximately 130 tons of high-quality sulfur-coated urea, fully demonstrating the scale benefits of industrial production.
With the deepening of precision agriculture and sustainable development concepts, intelligent fertilizers like sulfur-coated urea will play an increasingly important role in global food security and environmental protection. Its precise manufacturing process and excellent agronomic performance provide strong support for the green development of modern agriculture.
Advanced Coating Technology: The Future of Precision Fertilization
Sulfur-coated urea represents a significant advancement in controlled-release fertilizer technology, showcasing how specialized coating processes can revolutionize nutrient management. While sulfur-coating requires unique production setups, the broader fertilizer industry continues to innovate across various fertilizer granulation processes. Modern npk fertilizer production line facilities often incorporate multiple technologies, from traditional disc granulator machine systems to advanced double roller press granulator equipment, each suited for different product formulations. The disc granulation production line remains particularly effective for creating uniform, spherical granules, while specialized fertilizer granulator designs continue to evolve for specific applications.
This technological diversity extends across fertilizer types, with parallel innovations in organic fertilizer production line systems and bio organic fertilizer production line operations. The integration of equipment like the windrow machine for composting and sophisticated npk blending machine for precise nutrient formulation demonstrates the industry’s commitment to customized solutions. As global agriculture increasingly demands both efficiency and environmental responsibility, the continued refinement of these production technologies—from specialized coating systems to comprehensive npk fertilizer line operations—will be crucial in meeting the world’s growing food production needs while minimizing environmental impact.