Enhanced flocculation and dewatering of clay mineral dispersions

Results emerging from the several studies recently performed to provide fundamental understanding of the interplay between mineral pulp chemistry, flocculation performance, particle interactions, role of applied shear and dewaterability of model colloidal kaolinite and smectite dispersions are presented and discussed. Beneficial links between pulp interfacial chemistry (particle zeta potential), particle interactions (shear yield stress) and beneficial dewatering behaviour (batch settling rate and sediment solid loading), established through the influence of hydrolyzable metal ions, pH, temperature, high molecular weight polymer structure type (anionic polyacrylamide vs non-ionic polyethylene oxide) and shear, are shown. The application of the findings and new knowledge gained for a marked improvement in clay pulp dewaterability is discussed.

Interplay between kaolinite and smectite clay mineral pulp chemistry, flocculant structure and shear rate on dispersion dewaterability was studied. Flocculation with hydrolyzable metal ions and high molecular weight polyacrylamides: non-ionic homopolymer (PAM N), anionic carboxylate (PAM A) and sulphonate substituted (PAM S) copolymers and non-ionic polyethylene oxide (PEO), at different pH values, temperatures and shear rates revealed some useful relationships and optimum conditions for significant enhancement of clay pulp dewaterability.Figure optionsDownload as PowerPoint slide