Abstract
he clay particle morphologies in dilute aqueous suspensions of swelling clay minerals such as smectitesusing rheological techniques have previously been evaluated by applying Einstein's or Robinson's Newtonian equation, because there is little or no interaction between the particles in the system. However fortypical industrial aqueous suspensions of bentonite these equations are not applicable, because thesuspensions are non-Newtonian, i.e., plastic, in flow behavior and have an additional shear stress due to theparticle interaction. The relation between the shear stress, τ, and shear rate, σ, is described by the equationτ=η2σ+ αInσ+b. In this equation, the first term, i.e., the Newtonian term, is ascribable to hydrodynamic effects. The second and third terms are shear stress due to exclusively breaking and reformingthe particle interactions. Thus Robinson's equation was applied to the plastic viscosity or the Cassonviscosity of industrial bentonite suspension at high concentrations, and the effective volume of the particleswas presented. Then the effective volume was compared with each specific volume at the liquid limit and theswelling power.
