VOLUME FRACTION EFFECTS IN SHEAR RHEOLOGY AND ELECTROACOUSTIC STUDIESOF CONCENTRATED ALUMINA AND KAOLIN SUSPENSIONS

The electroacoustic and shear yield stress response of concentrated al umina and kaolin suspensions have been measured across a range of pH c onditions and volume fractions. The inter-relationship between the sur face properties as measured electrokinetically and the shear yield str ess is shown to scale in a straight forward manner for alumina particl es and a qualitative description has been developed from kaolin suspen sions. The pair-wise interaction between particles over the range of v olume fractions has been demonstrated to remain constant. The use of a semi-empirical electroacoustic volume fraction correction to the zeta potential, integral to the electroacoustic technique, appears reasona ble on the basis of the results presented herein. (C) 1998 Elsevier Sc ience B.V.