Interaction of Silica Particles Through a Liquid

Abstract

Measurements of the destruction time of the sediment column structure were carried out for different fractions of silica particles in NaCl and CaCl2 solutions whose concentrations were varied from 0.25 M to 2.0 M. On the basis of this study, linear relationships between the reciprocal of the destruction time of the silica sediment column structure and average diameter of the silica fraction, the density and the work of cohesion of the solutions were found. From these relationships the critical values of the particle diameter, the cohesion work and density of the solutions were determined for the destruction time equal to infinity (1/t = 0). The detachment force of one particle from another, which resulted from gravitational interaction, was calculated using the above critical parameters. For the system whose components have critical values the detachment force is found to be equal to the attachment force resulting from the interfacial interaction. Next, on the basis of our earlier study and Derjaguin's approximation, the radius of the contact plane and the attachment force between two silica particles were calculated. The detachment force decreased with increasing salt concentration, but the attachment force was nearly constant. It was found that, for a given salt concentration, the relationship between the reciprocal of the destruction time and the difference between the detachment and attachment forces was also linear. It appeared that for the silica column structure having critical parameters the values of the difference between the detachment and attachment forces were negative. This means that in the calculation of the attachment force between silica particles in the studied solutions an additional interaction should be taken into account.