Colloidal silicas are suspensions of fine amorphous, nonporous, and typically
spherical silica particles in a liquid phase. Usually they are suspended in an aqueous phase
that is stabilized electrostatically. Colloidal silicas exhibit particle densities in the range of
2.1 to 2.3 g/cm 3 .
Application:-
- In papermaking, colloidal silica is used as a drainage aid. It increases the amount of cationic starch that can be retained in the paper.
- High-temperature binders
- Investment casting - used as the inorganic binder in moulds
- An abrasive - for polishing silicon wafers
- As a binder or silica source in catalysts
- Desiccant
- Stabilizing and rigidizing refractory ceramic fiber blankets
- Abrasion resistant coatings
- Antisoiling – fills micropores to prevent take up of dirt and other particles into textiles.
- Surfactant – used for flocculating, coagulating, dispersing, stabilizing etc.
- Absorbent
- Colloidal silica is used in concrete densifiers and polished concrete.