Abstract
Small and spherical granules were made from CaCO3-powder by the simultaneous operation 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 x 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 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 made the granules smaller and non-spherical. Longer residence time θ made the granules more spherical with smooth surface remaining x unchanged.
