The problems affecting the forming of fertilizer granulation machine
can be discussed from the following three aspects: the influence of material properties, the influence of material temperature and the influence of material viscosity.
1. Influence of material properties:
The granulation properties of materials with different characteristics are quite different. The main physical parameters affecting granulation process and quality are melting point (or softening point), specific gravity, heat transfer coefficient, specific heat, crystallization characteristics, viscosity and liquid surface tension. Viscosity and surface tension mainly affect the molding quality of pelletized products, while other parameters mainly affect the cooling and curing speed of materials, thus affecting the output. Generally speaking, the higher the melting point, specific gravity and heat transfer coefficient of materials are, the smaller the specific heat is, and vice versa.
2. Effect of material temperature:
The temperature of material directly affects the production capacity of fertilizer granulator. The height here refers to the distance between the material temperature before granulation and its melting point or softening point. Generally speaking, the higher the temperature, the smaller the yield. Therefore, for the material with too high material temperature (generally more than 50 ℃ above melting point or softening point), it is recommended to conduct heat exchange treatment for the material before granulation, so as to give full play to the production capacity of the granulator.
3. Viscosity (or surface tension) of material:
The higher the viscosity and surface tension of the material at the corresponding temperature point, the fuller the hemispherical particles are; on the contrary, the flatter the hemispherical particles are. For general materials, the viscosity of molten materials decreases with the increase of temperature. However, our experimental study found that sulfur showed the opposite trend with other materials in a temperature range near the granulation temperature point. The discovery of this characteristic is particularly important for our technical practice in sulfur granulation.