Theory of Flocculation, Subsidence and Refiltration Rates of Colloidal Dispersions Flocculated by Polyelectrolytes

Victor K. La Mer and Robert H. Smellie Jr.
Columbia University, New York, N.Y.
Trinity College, Hartford, Connecticut

Abstract: The flocculation and subsequent subsidence of colloidal suspensions are markedly increased by the addition of flocculating agents; for example various starches and recently developed synthetic polymers.

The rate of flocculation depends not only upon the extent of adsorption of the agent (flocculant) but also upon the order of mixing and the character and extent of the subsequent agitation which determines the character of the floc formed. Electrolytes flocculate by reducing the electrostatic repulsions between charged particles, but long chain polymers produce flocs by a bridging mechanism which overcomes electrostatic repulsions.

Quantitative relationships are developed between the optimum concentration of flocculant and the rates of flocculation, subsidence, and particularly rate of filtration through the filter cake.

Clays and Clay Minerals; 1960 v. 9; no. 1; p. 295-314; DOI: 10.1346/CCMN.1960.0090118
© 1960, The Clay Minerals Society
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