Sedimentation and consolidation behaviour of mineral suspensions flocculated by adsorbing and nonadsorbing polymers - poster at SIS2008

Poster at 17th International Symposium on Surfactants in Solution on August 17-22, 2008 Berlin

Sedimentation and consolidation behaviour of mineral suspensions flocculated by adsorbing and nonadsorbing polymers

In many industrial applications stability and rheological behaviour of dispersions is adjusted using polymeric additives. Nonadsorbing polymers used as thickeners to stabilise formulations not only increase fluid viscosity but can also induce depletion flocculation. On the other hand adsorbing polymers are used mainly to flocculate suspensions for enhanced separation. Both types of flocculation are concentration dependent, high polymer concentration can lead to restabilization.

In this paper the sedimentation and consolidation behaviour of flocculated polydisperse quartz dispersions were investigated as function of polymer concentration. Depletion flocculation was induced by adding anionic polyacrylamide, electrostatic flocculation by adding a high charge density cationic polymer (PolyDADMAC).
Sedimentation and consolidation behaviour was measured as function of excess pressure applied using a multisample analytical centrifuge. This results in information about dispersion stability, packing density, dewaterability and rheological properties (compressive yield stress, elasticity).
The packing density as function of polymer concentration and centrifugal pressure applied was separately determined by X-ray adsorption. In addition to the average packing density obtained by analytical centrifugation this method allows to determine the local distribution of particle concentration.