What is colloidal silica?

What is Colloidal Silica?

Colloidal silica (SiO2) is silica particles that are suspended in a liquid. The liquid is denser than water and has been stabilized electrostatically to allow the particles to stay suspended in the solution. The silica particles are also very small and do not have a large density. Silica particle sizes are usually of the order of less than 100 nanometres. If the particles are too large, they will settle out of the solution. If the silica particles are too small, they are difficult to stabilize in a solution.

Applications of Colloidal Silica:

Colloidal silica has a wide range of applications across various industries due to its unique properties. Here are some common applications:

• Refractories: Colloidal silica is used as a binder in refractory materials, which are resistant to high temperatures and are used in kilns, furnaces, and other high-temperature industrial processes.

• High Temperature Binders: Its ability to form strong bonds at high temperatures makes colloidal silica suitable for use in high-temperature adhesives and binders.

• Investment Casting: In investment casting, colloidal silica is used to create molds that are heat-resistant and capable of capturing intricate details.

• Carbonless Paper: Colloidal silica is used in the production of carbonless paper to create a chemical reaction that transfers the writing pressure to the underlying paper.

• Catalysts: It can be used as a catalyst support or as a component in catalyst formulations due to its high surface area and porosity.

• Abrasive: Colloidal silica is used as an abrasive for polishing silicon wafers, glass, and other surfaces.

• Friction Modifier: It can be used to coat waxed floors, textile fibers, and railway tracks to increase traction by increasing friction.

• Antisoiling Agent: Colloidal silica can fill micropores in textiles, preventing dirt and other particles from adhering to the fabric, thus making it easier to clean.

• Absorbent: Due to its porous nature, colloidal silica can absorb liquids and gases, making it useful in applications such as spill cleanup and odor control.

• Surfactant: Colloidal silica can act as a surfactant, helping to flocculate, coagulate, disperse, and stabilize suspensions and emulsions in various industries.

• Wine and Juice Fining Agent: Liquid silicon dioxide (colloidal silica) is used as a fining agent in wine and juice production to clarify and stabilize the beverages.