Granulating Processes. II. Apparent Specific Volume and Breaking Strength of Solid/Liquid Mixed System in Relation to the Filling Properties

Abstract

The apparent specific volume (ASV) and the breaking strength (BS) of mixed systems were investigated in relation to the filling properties of the systems. Two inflection points were given on the BS vs. water content curves and on the ASV vs. water content curves. The air permeability method was adopted to examine the relationship between two inflection points and two critical points C1 and C2. The two inflection points were supported to be two critical points, because they were nearly consistent with those on the mean capillary diameter vs. water content curves. The changes of the extrusion weight and of the properties of mixed systems, with the lapse of time in the process of granulations, were discussed in relation to the changes of the particle compactness and of the breaking strength of mixed systems. In the extrusion type granulator, mixtures may first be compressed between basket wall and extruder, and then the powder bed may be deformed to be pushed out through holes in the basket wall by continued extrusive force.