Filtration Behavior of Slurries with Varying Compressibilities

Abstract

A novel filtration apparatus allows simultaneous measurements of filtrate volume, hydraulic pressure and cake thickness using slurry volumes on the order of 100 cm³ Differences in interparticle interactions were studied by varying the barium chloride concentration of 0.38-μm polystyrene latex and filtering at pressures between 2 and 100 psi. Cakes formed from these slurries are highly compressible for concentrations between 0.01M and 0.10M, moderately compressible for the 0.005M concentration, and incompressible for the 0.001M concentration. Plots of filtrate volume versus cake thickness were linear for the incompressible cakes, whereas the compressible cakes showed significant deviations, which were pressure dependent. The pressure distribution for the incompressible cake was found to be essentially linear as predicted from the resistance plots assuming constant α and ε. For the highly compressible cakes, most of the pressure drop appears to occur near the cake/medium Interface with only small changes occurring at the top of thp cakp.