Fast aggregation of colloidal silica

Journal Article · Sun Apr 15 00:00:00 EDT 1990 · Physical Review, A (General Physics); (USA)

DOI:https://doi.org/10.1103/PhysRevA.41.4379· OSTI ID:6973803

Martin, J E; Wilcoxon, J P; Schaefer, D; Odinek, J ^[1]

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1. Sandia National Laboratories, Albuquerque, New Mexico 87185 (USA)

The aggregation kinetics of colloidal silica is highly dependent on conditions such as the {ital p}H and salt concentration. In this paper we investigate the aggregation of colloidal silica under conditions that promote rapid growth, contrasting our findings with earlier investigations of the slow growth of silica. A number of interesting effects are observed, including power-law growth of the mean aggregate radius, dependence of the aggregation rate on concentration and the chemical nature of the salt used, a reduced aggregate fractal dimension, fragmentation of the fast aggregates under changing solution conditions, and shear-induced restructuring of aggregates. Finally, we present evidence that the fractal dimension of aggregates is not strongly universal, but depends weakly on such factors as the solution concentration. We conclude that although the diffusion-limited cluster-cluster aggregation model gives a good first-order description of rapid aggregation, real systems exhibit richer behavior that is not given to such a facile interpretation.

• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6973803
• Journal Information: Physical Review, A (General Physics); (USA), Vol. 41:8; ISSN 0556-2791
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
SILICA
AGGLOMERATION
COLLOIDS
COULOMB FIELD
CRYSTAL GROWTH
FLOCCULATION
KINETICS
QUANTITY RATIO
TEMPERATURE DEPENDENCE
CHALCOGENIDES
DISPERSIONS
ELECTRIC FIELDS
MINERALS
OXIDE MINERALS
OXIDES
OXYGEN COMPOUNDS
PRECIPITATION
SEPARATION PROCESSES
SILICON COMPOUNDS
SILICON OXIDES
360601* - Other Materials- Preparation & Manufacture