Rheology of settling suspensions

Jan Gustafsson*, Martti Toivakka, Jouni Karhu, Kari K. Koskinen

*Corresponding author for this work

Research output: Chapter in Book/Conference proceedingForeword/postscriptScientific

Abstract

The flow properties of suspensions of industrial grade magnetite, as well as spherical model samples of ceramic beads and glass beads have been investigated with a modified Couette rheometer. The suspensions exhibited instability to sedimentation due to their high density and large particle size. In order to homogenise the suspension for rheological measurements, an additional upward force was applied by pumping the stirred suspensions through the measuring cell. Due to the difference in density between the materials, it was possible to analyse the impact of different settling properties on the suspension rheology. It was found that the shear stress increased with increasing density for samples of the same size and at the same solids contents. For magnetite suspensions, the shear stress decreased with increasing size, but for ceramic and glass beads the influence of size on the shear stress remained unclear, due to small absolute shear stresses and small variations between the samples. However, the measuring system was found to be useful for determining the flow properties of settling samples.

Original languageEnglish
Title of host publicationRheological materials in process industry / ReoMaT Final Report
EditorsMarkku kataja
Pages21-33
Number of pages13
Edition2428
Publication statusPublished - 2008
MoE publication typeB2 Part of a book or another research book

Publication series

NameVTT Tiedotteita - Valtion Teknillinen Tutkimuskeskus
Number2428
ISSN (Print)1235-0605

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