Potassium sulfate has the characteristics of moisture absorption, easy caking and good water solubility. Potassium sulfate fertilizer granules can release fertility slowly on crops. Roller press granulation process is simple, non-corrosive, mature and reliable technology, which is widely used in fertilizer granulation industry, and has good granulation effect on potassium sulfate powder.
Potassium sulfate fertilizer has low pelletizing forming rate because of its own characteristics. It is necessary to pay attention to the regulation of key factors in the industrial production of roller press granulation line to improve the pelletizing rate and particle quality of potassium sulfate.
Moisture is the key factor affecting the extrusion granulation of potassium sulfate particles. Excessive moisture will reduce the forming rate of potassium sulfate extrusion granulation. Excessive moisture will lead to excessive potassium sulfate bonding on the roller press and increase the energy consumption of later drying process. The water condition test of potassium sulfate powder was carried out to determine the optimum water content in production.
The return material of screening in roller press granulation production line has an effect on granulation. In the common process of compound fertilizer extrusion granulation, after the fertilizer powder is put into the roller press granulator, the granulated fertilizer particles enter the follow-up process, and the unqualified fertilizer is re-extruded by mixing the returned form and the raw material powder into the granulator. With the addition of recycled materials, the moulding rate will be improved and the particle strength will also be improved.
The extrusion pressure of the roller press granulator is also a key factor in potassium sulfate granulation. In the process of extrusion granulation of potassium sulfate powder, the forming rate increases first and then decreases sharply with the increase of pressure. The increase of initial extrusion pressure is conducive to more powder extrusion between rollers. Excessive pressure results in the crushing of some formed particles. Setting suitable extrusion parameters of equipment is beneficial to increase the processing capacity of counter-roll granulator.