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Equilibrium-State Density Profiles of Centrifuged Cakes of Flocculated Suspensions

Published online by Cambridge University Press:  15 February 2011

Wei-Heng Shih ,
Wan Y. Shih ,
Seong-Il Kim  and
Ilhan A. Aksay
Wei-Heng Shih
Affiliation:
Department of Materials Engineering, Drexel University, Philadelphia, PA 19104
Wan Y. Shih
Affiliation:
Department of Chemical Engineering, and Princeton Materials Institute, Princeton University, Princeton, NJ 08544
Seong-Il Kim
Affiliation:
Ferro Corporation, Santa Barbara, CA 93117.
Ilhan A. Aksay
Affiliation:
Department of Chemical Engineering, and Princeton Materials Institute, Princeton University, Princeton, NJ 08544
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Abstract

Many advanced ceramics are formed by colloidal consolidation using techniques such as sedimentation, centrifugation, or pressure filtration. In all these, the minimization of density variations of various colloidally-consolidated cakes has not been examined systematically until recently. Schilling et al. used γ-ray densitometry to study the density variations in a sedimented cake and showed that the sediment of a flocculated alumina suspension exhibited significant density variations within the cake whereas the sediment of a dispersed alumina suspension showed a constant density profile. Auzerais et al. used a medical X-ray computer tomography (CT) to study the settling of dispersed and flocculated silica suspensions and obtained similar results: The sedimented cake of a dispersed silica suspension was fairly uniform whereas those of flocculated silica suspensions exhibited significant density variations. However, Shih et al. examined pressure-filtered cakes of flocculated alumina suspensions with γ-ray densitometry and showed that the density profiles of pressure-filtered cakes of flocculated alumina suspensions were uniform, in contrast to their sedimentation counterparts which showed significant density variations. These studies illustrate that how the local density varies within a consolidated cake depends not only on the suspension conditions but also on how the suspensions are consolidated, e.g., the consolidation pressure.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 289: Symposium M – Flow and Microstructure of Dense Suspensions , 1992 , 251
Copyright
Copyright © Materials Research Society 1993

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References

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