Drying and screening are indispensable links in the NPK fertilizer production line, playing a key role in ensuring the quality of fertilizer products.
The fertilizer granules after granulation contain a certain amount of moisture. If not removed in time, they are not only prone to clumping, but also affect the storage period and effectiveness of the fertilizer. Therefore, the particles first enter the drying process.
Drying equipment usually uses fertilizer dryers, commonly including drum dryers. The particles slowly move forward in the dryer as the drum rotates, while high-temperature hot air is blown in from the other end. Hot air comes into full contact with particles and carries away the moisture in the particles through heat transfer. During the drying process, it is necessary to strictly control the temperature and residence time. Excessive temperature may lead to the decomposition of certain components in fertilizers, affecting nutrient content; If the residence time is insufficient, the ideal drying effect cannot be achieved..jpg)
After drying, the moisture content of the particles is significantly reduced and reaches the appropriate standard before entering the screening stage. The purpose of screening is to classify particles according to their size, ensuring that the particle size of the product is uniform and consistent.
Fertilizer vibrating screen is the main equipment in the screening process. It causes particles to bounce on the sieve through high-frequency vibration. Particles smaller than the mesh size fall through the sieve and become fine powder; Particles larger than the mesh size remain on the sieve and continue to move forward. Particles within the qualified particle size range are collected and enter the next process.
The processing methods for unqualified particles screened out are different. Oversized particles usually enter the fertilizer crusher for crushing, and the crushed material participates in the granulation process again; Small fine powder is usually returned to the mixing process and mixed and granulated again with new raw materials.
The drying and screening processes are closely coordinated, with drying providing a suitable material state for screening, and the screening process further ensuring the quality and uniform specifications of fertilizer particles. After these two processes, the NPK fertilizer particles are one step closer to becoming the final qualified product.