Abstract
A series of sonication tests were performed on dilute silica suspensions flocculated with the use of a polyacrylamide-based flocculant, A100, to investigate the reversibility of floc destruction and formation. The tests were performed as a function of sonication energy and dosage. It was demonstrated that breakage of flocs does not occur down to the primary particles over the studied range of experimental conditions. Measurement of settling rate and image analysis indicated that depending on the dosage, broken flocs reach a steady state size following continuous breakage. Higher flocculant dosage resulted in generation of larger flocs following breakage. Adsorption studies indicated that adsorption density of the polymer on mineral surface did not change as a result of breakage of flocs. Analysis of laser light scattering data indicated a gradual increase in the size of the broken flocs following sonication while flocculation at higher dosages did not improve the rate at which the flocs re-grow. However, increasing the dosage resulted in re-growth of larger flocs following breakage.