A method for determining the settling behavior of dense suspensions

Authors

  • A. M. Al Taweel,

    Corresponding author
    1. Chemical Engineering Department, Technical University of Nova Scotia, P.O. Box 1000, Halifax, N.S. B3J 2X4
    • Chemical Engineering Department, Technical University of Nova Scotia, P.O. Box 1000, Halifax, N.S. B3J 2X4
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  • H. A. Farag,

    1. Chemical Engineering Department, Technical University of Nova Scotia, P.O. Box 1000, Halifax, N.S. B3J 2X4
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    • Chemical Engineering Department, Alexandria University, Egypt.

  • O. Fadaly,

    1. Chemical Engineering Department, Technical University of Nova Scotia, P.O. Box 1000, Halifax, N.S. B3J 2X4
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  • G. D. M. Mackay

    1. Chemical Engineering Department, Technical University of Nova Scotia, P.O. Box 1000, Halifax, N.S. B3J 2X4
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Abstract

An accelerated method for evaluating the compaction behavior of dense suspensions is presented, in which centrifugal force is used to enhance settling rates and a highly-compensated compound pendulum is used to detect the resultant small shifts in centre of gravity.

The results obtained by following the temporal variation in suspension characteristics indicate that a Richardson and Zaki type of equation can describe the subsidence of very concentrated suspensions. The exponent n, and the ultimate sediment compaction density were found to be strongly influenced by small changes in the physicochemical characteristics of the suspended solids.

Abstract

On présente une méthode rapide pour évaluer le comportement au compactage de suspensions denses; on y emploie la force centrifuge pour augmenter les vitesses de sédimentation et l'on utilise en pendule composé à forte compensation pour déceler les faibles déplacements du centre de gravité.

Les résultats qu'on obtient en suivant la variation en fonction du temps des caractéristiques des suspensions indiquent qu'on peut décrire l'affaissement de suspensions très concentrées, au moyen d'une équation du type Richardson-Zaki. On a trouvé que l'exposant n et la densité finale du sédiment compacté étaient fortement influencés par de faibles changements des caractéristiques physico-chimiques des solides en suspension.

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