Complicated Flow Behavior of Silica Particles in Concentrated Slurry

Abstract

The motion of particles in concentrated slurry was observed directly by using a confocal laser scanning microscopy. For observation of particles inside a slurry, the silica particles were dispersed into a glycerol solution, so that the slurry shows transparency. In this study, the two types of slurries were prepared for examining the influence of the diameter distributions of particles on the rheological measurement. A slurry was consisted of mono-dispersed silica particles, another contained mono-dispersed particles with small amount of poly-dispersed particles. The mono-dispersed slurry showed a shear-thinning behavior. In the observed images, the particles in the slurry flowed at the same rate with keeping the particle-coordinated structures. The mixed slurry containing small amount of poly-dispersed particles also showed shear-thinning, but the viscosity becomes considerably higher. The slip stick phenomena of due to co-existence of the large particles and small particles were observed. The rotating behavior of particles was also observed. This indicated that this phenomena increase the viscosity.