Colloidal silica for foundry and refractory

What is Colloidal Silica/ Silica Sol?

Colloidal silica is a dispersion of amorphous silicon dioxide (silica)
particles in water. These amorphous silica particles are produced by
polymerizing silica nuclei from silicate solutions under alkaline conditions to
form nanometer sized silica sols with high surface area. A charge is then
induced on the silica nanoparticle surface that allows the silica particles to
repel one another and form a stable dispersion, or colloid.



Colloidal Silica Characters:

Colloidal silicas are produced in a variety of grades that range in a number of
factors. Particle size typically varies from 5nm to 40nm, and particle size
distribution can vary from narrow to wide depending on the manufacturing
process. Standard colloidal silica is stable at a pH from 8 - 10.5 and carries
an anionic surface charge that is stabilized with sodium or ammonium. In
certain grades, some of the silicon atoms in the silica particle are replaced
with aluminate ions to allow for enhanced stability in a wider pH range,
usually 3.5 - 10.5.



Colloidal Silica Application:



Densification of concrete, cement, and other materials.

Fine retention in paper manufacturing.

Enhanced bonding of waterborne adhesives.

Improved surface friction and anti-slip properties.

Wastewater filtration flocculant.

Investment casting binding.

Anti-soilant textile coatings.

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