The forming mechanism of the extruded granulated material on the NPK fertilizer production line:
At present, the general explanation of the material forming mechanism in the extrusion process is: After the material is under pressure, its particles will be rearranged and the air between the particles will be removed, thereby removing the voids in the material.
After the material is further compressed, the material particles will be in the following two situations due to their different properties: When the material is brittle, part of the particles will be broken, thereby filling the remaining gaps. In addition, if the free chemical bonds on the new surfaces formed when the particles are broken cannot be quickly saturated by atoms or molecules in the environment, then strong recombination bonds will be formed when the new surfaces are in contact with each other.
When the particles are plastic, the particles will deform and flow, resulting in strong van der Huawei. In fact, the above two phenomena exist at the same time, but for a particular material, one of them may play a leading role.
In the NPK fertilizer production process of extrusion, the particles of the material may also form a solid bridge. The energy supplied into the system in the form of pressure will generate heat energy at the contact point of the material particles to melt the material. When the temperature of the material drops, a solid bridge is formed.
Extrusion granulation NPK fertilizer manufacturing process main equipment:
1, forced feeding machine
One of the advances made in the extrusion granulation compound fertilizer production line technology is the use of forced feeding on the extruder, which is often achieved with the help of the propelling force of the screw. The extrusion process adopts a free feeding form by means of gravity.
Forced feeding, it is easy to control the feeding speed and reduce the slip phenomenon in the bite zone. More importantly, the material can be partially degassed and compacted in advance in the forced feeder, so that the product quality is greatly improved.
2, crushing equipment
The flakes obtained by extrusion must undergo so-called granulation processes such as crushing and sieving to obtain granules of the required size. The progress made in the granulation equipment is mainly due to the many experience gained in the relationship between the form of the crushing equipment and the product.