Generally, the factors affecting the extrusion granulation effect of the
NPK fertilizer production line are divided into two categories. One is related to the physical properties of raw materials, and the other is related to the characteristics of the extruder.
1. The characteristics of raw materials
The nature of the raw material has a great influence on the extrusion granulation effect of the compound fertilizer production line.
(1) Moisture
To enter the bite zone, the material must have good fluidity, which requires a very low water content of the material. Of course this is not to say that dry raw materials are ideal. Processing raw materials into dry products will greatly increase the processing cost. Moreover, a small amount of water is still beneficial to the extrusion molding process. Different materials have different ranges of water content.
(2) Particle characteristics
The brittleness and plasticity of the material particles will cause the material to exhibit different forming mechanisms. The size and shape of the material particles will affect the bulk density of the material.
(3) Temperature
The temperature of the raw material has a great influence on the extrusion and granulation molding of the
NPK fertilizer production process, and during the extrusion process, the friction between the particles will generate heat and increase the temperature of the material.
(4) Binder
Among the properties of raw materials, another important factor affecting the extrusion process is the use of binders. For some materials, a binder is needed to complete the extrusion molding process. In the fertilizer industry, urea and potassium chloride are widely used as binders due to their good plasticity.
2. Features of extrusion granulator
(1) Roll width
In the extrusion process, the material is formed due to the pressure exerted by the extruder. The pressure is obviously an important factor affecting the extrusion granulation effect of the compound fertilizer production line.
(2) Gap between rolls and roll diameter
The gap between the rolls determines the thickness of the pressed sheet and therefore also determines the production capacity of the extruder. However, under a certain pressure, for a given material, there is a suitable sheet thickness.
(3) The surface shape of the roll
(4) The rotation speed of the roll. Another factor that affects the extrusion granulation effect of the
NPK fertilizer manufacturing process is the speed of the rolls.
