Influence of Humidity on Binderless Granulation in a Spouted Bed

The binderless granulation method using a spouted bed is a method of using the adhesion force of raw powder. In order to increase the adhesion force among fine particles, the raw powder and the fluidizing gas were humidified. However, results of granulation revealed no significant effects of humidification. Humidification of raw powder did not change the behavior in the granulator. To clarify the cause, adhesion force and spatula angle of raw powders were measured. Consequently, we found that the cohesive fine powders suitable for binderless granulation formed agglomerates, while absorbing moisture within the agglomerates.