Predicting Viscosity of Limestone–Water Slurry

Abstract

The rheological behavior of limestone–water slurry samples was investigated for different volume concentrations, particle size distribution and slurry temperature. Experiments were conducted over a range of volumetric solids concentration (Q= 0.20 - 0.46) in shear rate range of 1-300 s -1 . The slurry showed Newtonian behavior up to a volumetric solids concentration of 37.8 vol. %, beyond which the slurry was highly pseudoplastic in nature and fitted excellently to a non-Newtonian Power law model. The relative viscosity (N r ) of the mixture slurry, defined as the suspension viscosity over the viscosity of the suspending medium was found to be increasing exponentially when Q exceeds 0.404. By adopting an experimental approach, the rheological data indicated that Q might reach 0.462. Using the ( 1-N r -1/2 ) -Q relationship proposed by Liu, the theoretical maximum solids fraction (Q m ) was evaluated as Q m = 0.504 for the given slurry samples and was then used to predict the relative viscosity (N r ) by some existing models. Five empirical models namely; Liu, Dabak et al., Krieger-Dougherty, Mooney and Chong et al. were considered for the purpose. Liu’s model better predicted the relative viscosity and thus would be helpful in evaluating the hydraulic parameters accurately for design of limestone slurry pipelines operating at high concentrations.