Process variables of instant granulator and spheroniser: I. Physical properties of granules, extrudate and pellets

Abstract

The influence of process variables of a continuously working instant Nica granulator, and those of a spheroniser on the stability of moisture content during the process, the surface morphology, friability, packing and flow properties of pellets was evaluated. A complete six-factor, two-level study design was used. The moisture content of granules and extrudate corresponded well to the amount of water used as a granulation liquid. Hence, until the spheronisation stage, the stability of moisture content was maintained. During spheronisation, the moisture content decreased due to the effect of residence time and friction plate speed. The surface morphology of pellets was dependent on the amount of water used; with a higher water amount the surface was smoother. The process variables of the spheroniser explained most significantly the changes in packing properties of pellets: the bulk and tapped density increased with increasing load, time and speed in the spheroniser.