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Effect of Particle Packing on the Filtration and Rheology Behavior of Extended Size Distribution Alumina Suspensions
Author(s) -
Smith Peter A.,
Haber Richard A.
Publication year - 1995
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1995.tb08883.x
Subject(s) - rheology , porosimetry , suspension (topology) , shear rate , materials science , particle size , composite material , viscosity , particle size distribution , rheometry , atomic packing factor , apparent viscosity , flocculation , casting , chemical engineering , mineralogy , porosity , chemistry , porous medium , crystallography , mathematics , homotopy , pure mathematics , engineering
The effect of particle packing on the rheology and casting behavior and cast cake characteristics of aqueous alumina suspensions (5O vol%) was investigated using the Andreasen approach. Varied packing was produced by blending two starting materials that differed in average size by a factor of 10. Formulations closest to ideal packing lowered viscosity. Specifically, the lowest viscosity suspension, 196 mPa s, was produced with the distribution closest to the ideal packing distribution. Typically, a well‐dispersed suspension (characterized by low viscosity) casts slower than one of poorer dispersion given the same solids content. However, the suspension that provided the lowest viscosity cast at a rate of 0.41 mm 2 /s, which was the fastest rate of the compared formulations. Therefore, suspensions consisting of extended size distributions do not necessitate slow filtration rates. The colloidal properties of the individual starting materials, low shear rate rheology, 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 flow channels that developed in the casts. Low shear rate rheology confirmed the presence of flocculation that was first suggested by the porosimetry results.