Abstract
Small and spherical granules were made from CaCO3-powder by the simultaneous process of granulation, grinding and separation in a continuous rotating conical vessel. The shape characteristics of the granules were evaluated by a pair of shape indices: φ is a measure of sphericity, and ζ is that of surface roughness. φ, ζ and granule size χ were plotted on three-dimensional graphs for various operating conditions of the granulator.
The result was that the increase in rotation speed of the vessel n was found to be more effective in obtaining smaller and spherical granules with smooth surface. The increase in ball charge B and feed ratio W produced small and non-spherical granules. Longer residence time θ produced more spherical granules with smooth surface with χ remaining unchanged.
† This report was originally printed in J. Soc. Powder Technology, Japan. 30(8), 563-569 (1993) in Japanese, before being translated into English by KONA Editorial Committee with the permission of the editorial committee of the Soc. Powder Technology, Japan.
