In an organic fertilizer disc granulation production line, the screening process serves as the critical link connecting granulation with the final product packaging. It directly determines the uniformity and pass rate of the finished granules, and constitutes a vital stage in ensuring the overall quality of the organic fertilizer.
The screening stage immediately follows the granulation, drying, and cooling processes. Its primary objective is to isolate qualified granules while removing impurities and substandard products. Granules—having been formed by the disc granulator, then dried and cooled—are transported via conveyor systems into the screening equipment, where they are separated according to size through the grading action of the sieves.
The screening equipment is outfitted with multiple layers of sieves featuring varying mesh sizes: the upper layers separate oversized clumps and granules; the lower layers sift out fine powders and impurities; and the intermediate layers isolate the qualified granules—those that are uniform in size and meet established standards. Any oversized, substandard granules are conveyed to a crushing unit; once pulverized, they are returned to the granulator for reprocessing and reuse.
The key to effective screening lies in precisely controlling the sieve mesh size and the equipment’s rotational speed. The sieves must be adjusted to align with the specific size specifications of the finished granules; a rotational speed that is too high can cause granules to scatter, resulting in incomplete screening, while a speed that is too low will compromise production efficiency. Additionally, the sieves must be cleaned regularly to prevent clogging.
Although the screening stage may appear simple, it plays a pivotal role in enhancing the appearance and quality of the organic fertilizer, facilitating the recycling of raw materials, and minimizing material loss—making it an indispensable and critical step within the organic fertilizer disc granulation production line.
