(237f) Effect of Particle Size Distribution On Slurry Rheology

Understanding rheological properties of slurries has been an important but challenging issue for many applications such as cosmetics, pharmaceuticals, paint, and nuclear waste treatment. Many physicochemical parameters such as particle size, pH, ionic strength, and mass/volume fraction of particles can influence rheological properties of slurry. Among such parameters, the particle size distribution of slurry is especially important since it mainly differentiates between colloidal and non-colloidal slurry. We studied rheological properties of several different nuclear waste simulants, which are characterized by high ionic strength and solid contents but have different particle size distributions. Using rheological and particle size analysis, it was found that the relative amount of ?colloid-sized' particles in slurry appears to alter rheological characteristics such as Newtonian or Bingham plastic behavior and the effectiveness of rheological modifiers to control rheological properties. This study suggests that one may need to implement the particle size distribution as a critical factor to understand and control rheological properties in nuclear waste treatment plants such as the U.S. Department of Energy's (DOE) Hanford and Savannah River sites, since the particle size distributions vary significantly for different types of nuclear waste slurries.