Sedimentation Kinetics of Flocculated Suspensions II: Sedimentation below the Critical Height

Aside from the phenomenological equation by Egolf and McCabe and by Robinson, no attempts have appeared in literature in the past to quantitate terminal sedimentation characteristics of flocculated suspensions. The physical factors involved are suggested here, taking into account electrical effects and geometric factors contributing to friction. The equation of settling emerges as a linear combination of exponential decays—viz., [x -Hu] =A1e−w1τ +A2e−w2τ, where x is the height of the sediment at time τ,Hu is the final height, and A and w are constants. From the data it would appear that the friction,B, exerted is both viscosity (η) and dimension (R) dependent and of the form B(η,R) =Γ.eζeμR where μ ϵ, and Γ are system-dependent constants.