The Effect of Colloidal Forces on the Sedimentation and Reslurrying Characteristics of Silica Slurries

Preliminary work has been completed to investigate the effect of particle-particle interaction forces on the flow properties of silica slurries. Classically Hydrotransport studies have focused on the flow of coarse granular material in Newtonian fluids. However, with current economical and environmental pressures, the need to increase solid loadings in pipe flow has lead to studies that examine non-Newtonian fluid dynamics. The flow characteristics of non-Newtonian slurries can be greatly influenced through controlling the solution chemistry. Here we present data on an “ideal” slurry where the particle size and shape is controlled together with the solution chemistry. We have investigated the effect of adsorbed cations on the stability of a suspension, the packing nature of a sediment and the frictional forces to be overcome during reslurrying. A significant change in the criteria assessed was observed as the electrolyte concentration was increased from 0.1mM to 1M. In relation to industrial processes, such delicate control of the slurry chemistry can greatly influence the optimum operating conditions of non-Newtonian pipe flows.