EFFECT OF PARTICLE PACKING ON THE FILTRATION AND RHEOLOGY BEHAVIOR OFEXTENDED SIZE DISTRIBUTION ALUMINA SUSPENSIONS

The effect of particle packing on the theology and casting behavior an d cast cake characteristics of aqueous alumina suspensions (50 vol%) w as investigated using the Andreasen approach, Varied packing was produ ced by blending two starting materials that differed in average size b y a factor of 10, Formulations closest to ideal packing lowered viscos ity, Specifically, the lowest viscosity suspension, 196 mPa . s, was p roduced with the distribution closest to the ideal packing distributio n, Typically, a well-dispersed suspension (characterized by low viscos ity) casts slower than one of poorer dispersion given the same solids content, However, the suspension that provided the lowest viscosity ca st at a rate of 0.41 mm(2)/s, which was the fastest rate of the compar ed formulations, Therefore, suspensions consisting of extended size di stributions do not necessitate slow filtration rates, The colloidal pr operties of the individual starting materials, low shear rate theology , and mercury porosimetry were used to explain the unexpected casting behavior, The dispersion and structure formation within the suspension were investigated using electrokinetic sonic amplitude measurements, Mercury porosimetry characterized the from channels that developed in the casts, Low shear rate theology confirmed the presence of flocculat ion that was first suggested by the porosimetry results.