Rheological Behavior of Kaolin and Calcium Carbonate Slurries, from a Small Distortion to Rupture

Abstract

The rheological behavior of flocculated Kaolin and Calcium Carbonate were examined by a torsional shearing test on a cone-and-plate rheometer. All of these sol type solutions behaved more or less like rigid bodies within small shear and suddenly broken down with increasing shear at several points in the slurries. Break down was progressed intermittently to give a step-wise stress overshoot. When shear rate was less than a limiting value, sliding layer was developed near the solid surface. The phenomenon was supposedly due to the dilatant nature of the slurry. Over the limiting shear rate, stress break-down occurred at once and as a whole without any stress overshoot, that is quite similar to a Binghammodel fluid. Steady state properties also varied at this limiting shear rate.