Colloidal silicas are suspensions of fine amorphous, nonporous, and typically spherical silica particles in a liquid phase.
In papermaking colloidal silica is used as a drainage aid. It increases the amount of cationic starch that can be retained in the paper. Cationic starch is added as sizing agent to increase the dry strength of the paper.
High temperature binders
Investment casting - used in moulds
An abrasive - for polishing silicon wafers
It increases the bulk & tapped density of powders and granules
It is used as a free-flow agent to assist powder flow, e.g. in tabletting, by reducing the angle of repose of bulk powder.
Stabilizing and rigidizing refractory ceramic fiber (fiberfrax) blankets
Increasing friction - used to coat waxed floors, textile fibers and railway tracks to promote traction
Antisoiling - fills micropores to prevent take up of dirt and other particles into textiles
Surfactant - used for flocculating, coagulating, dispersing, stabilizing etc.
Liquid silicon dioxide (colloidal silica) is used as a wine and juice fining agent.
Colloidal silica is used in concrete densifiers and polished concrete.
In manufacturing Quantum dots, small semi-conductors used in various scientific research settings
used as an ingredient in many "Ceramic Coatings"