Some Observations on the Flow Behavior of Clay-Water Suspensions

Abstract

Hereunder is presented a brief report of the investigation that was made of the flow behaviors of clay-water suspensions, using a Couette type viscometer usable in a wide range of shear rates.The flow curves (rotational velocity ω vs. torque T) have been obtained at various pH values which may be the effectual determinant of the internal time scale τ as well as at various time derivatives of rotational velocity ω and various maximum rotational velocities ωmax corresponding to the external time scale t.The flow behaviors can be grouped into typical three classes as follows, (1) plastic(2) negative thixotropic(3) positive thixotropicThe dependence of shearing torque on pH value measured at 90 r.p.m. indicated the minimum point at pH≈7.5.The analytical treatments have been developed using the mechanical simulation models constructed with the internal clay structure revealed in the sedimentation experiments.The dependence of flow behavior on the external time scale was also investigated using the electric circuit simulation models constructed to analyze its time sensitive properties especially, from which were obtained, the qualitative correspondences to the flow behaviors.