The Influence of Surface Chemistry on the Rheology and Flow of Flocculated Particulate Suspensions

The role of the surface chemistry of particles in controlling the rheology of flocculated particulate suspensions is discussed. The case is developed for the measurement of the shear yield stress of a suspension of alumina particles and a theoretical interpretation of the yield stress is presented which is able to describe the effect of particle size distribution, solid loading, pH and hence, electrokinetics of the suspension. Scaling of the data to the maximum yield stress at a given volume fraction provides a means of removing particle size and volume fraction related effects and gives information as to the mode of failure in yielding of suspensions and the mode of action of molecular additives.