Characterisation of short-range structure of silica aggregates—implication to sediment compaction

In this study, both short-range and long-range structures of silica aggregates were studied by small-angle light scattering. The silica particles were aggregated by using different concentrations of KCl and MgCl 2, with and without continuous shear. It was found from both small-angle light scattering and transmission electron microscopy (TEM) measurements that the aggregates had a compact short-range structure and a looser long-range structure. The floc sediments were studied by allowing the silica aggregates to settle under gravity, as well as having them consolidated by centrifugation. The results show that under gravity and lower centrifugation force (50× g), the short-range structure of silica aggregates affects the compacted sediment structure, while under higher centrifugation force (453× g), the sediment structure is independent of the short-range structure of the aggregates.