Rheological Factors for Bentonite Suspensions

Abstract

The flow behavior of bentonite colloidal suspensions is given i n terms of the stress-strain relations with respect to variables of concentration, suspension medium, hydrogen-ion concentration, temperature, a n d the successive application of shear stress. Repeated cycling (successive reruns of upcurve a n d downcurve) caused thixotropic hysteresis loops which decreased in size to a final constant a n d reproducible flow curve. A hysteresis loop did not appear for a mixture of less than 20 wt% bentonite a n d glycerin. The flow curves are discussed i n terms of bondings in "cardhouse" a n d "blockhouse" models for dilute a n d concentrated suspensions respectively. Eyring's rate theory of viscosity is discussed briefly in terms of the well-known generalized viscosity equation which was applied successfully t o given flow curves. Physical and chemical characterizations are compared in terms of thixotropic flow models for aqueous, glycerol, a n d oil (Bentone grease) suspensions.

Transitions haute pression. Zone d'indifférence des halogénures du rubidium

“…Néanmoins, parmi les plus importants, il faut citer ceux de Zeto et al [8,9] sur le bismuth et de Kaneda et al [10] concernant le fluorure d'ammonium. Gabrysh et al [11] ont également fait appel à la zone d'indifférence pour détecter l'influence des impuretés sur les transitions du camphre et du phosphore. [12], transmet isostatiquement les pressions jusqu'au voisinage de 60 kbar.…”