Is sweep-flocculation relevant to saponite aggregation?

Synthetic saponites with various Cationic Exchange Capacities were aggregat ed at pH 8.0 in a stirred vessel by hydrolysed aluminum species. Flee growt h was followed by Fraunhoffer laser diffraction and the efficiency of clari fication was assessed from conventional residual turbidity and sediment vol ume measurements. We show that the aggregation mechanisms are layer-charge dependent and can not be described by the widely accepted sweep-flocculatio n model. (C) 1998 Published by Elsevier Science Ltd. All rights reserved.