The maximum amounts of liquid imbibed in colloidal silica, perlite and diatomaceous earth at their pendular stage were determined graphically from the variations of the agglomerate diameter and residual specific pore volume of each mixture with the amount of the liquids added.
The ratio of the amount of liquid imbibed at the powder limit (the end of its pendular stage) to that measured by the rub-out method (JIS K5101-1964) for the colloidal silica was found to be much larger than those for the perlite and the diatomaceous earth tested.
The total specific pore volume of each colloidal silica showed an inherent value irrespective of the kind of liquid at the powder limit, although the values of the agglomerate diameter and residual specific pore volume were different.
These findings are useful in the utilization of colloidal silica for making powders mixtures from liquid drugs.
