Some manufacturers first dry the coarse powder or irregular small pieces of organic fertilizer until the moisture content is only 20 ~25%, and then use the flat die granulator or the double roller press granulator to extrude the dried organic fertilizer into columnar or flat spherical particles, although this practice is more convenient to use, but the fluidity is still not good, not suitable for machine sowing, and poor appearance and bad appearance. 2, some manufacturers will be coarse powder or irregular small pieces of organic fertilizer first use flat die extrusion granulator extrusion into short columnar particles (due to high moisture, high fiber content, columnar particles also have a certain plasticity), and then polished to form spherical particles, and then the spherical particles for dry cooling screening, to obtain qualified particles, this method of raw materials do not need to be treated, The water order is reduced, and the production cost is greatly reduced, but this method also has some fatal weaknesses, that is, organic fertilizer is easy to arch material, easy to plug material and easy to bond equipment, while the output is small and the power consumption of the extrusion process is high.

3, some manufacturers use the traditional disc granulator or rotary drum granulator need to dry the coarse powder or irregular small chunks of organic fertilizer (moisture < 15%), crushed into a very fine (more than 100 mesh) powder and then add binder and inorganic fertilizer, and the amount of binder and inorganic fertilizer added in organic fertilizer can not be greater than 30%, this method is enough to make spherical particles, but because the organic fertilizer in the processing process will be fully hydrated powder and water granulated and then dried, repeated many times, Therefore, the processing cost is quite high, and due to the small density of organic fertilizer number, the strength of the grain is low, which is not conducive to storage, transportation, and machine sowing.