Effect of Particle Size Distribution on Rheological Properties of Fly Ash Slurries at High Concentrations

The rheological behavior of fly ash slurry at any concentration has a marked dependence on particle size distribution. Five groups of fly ash samples having different particle size distribution are prepared by wet sieving to simulate the fly ash collected from different fields of electrostatic precipitator hoppers. Six suspensions of different solid concentrations (by weight) are prepared from each sample to study the effect of solid concentration on the rheological parameters. The study shows that the fly ash slurries above a solid concentration of 4 0 % by weight are non-Newtonian and that the experimental data fit a simple Bingham plastic model. It further shows that the rheological parameters increase monotonically with the solid concentration and have higher values for finer particulate suspensions.