Colloidal silica is suspension of fine amorphous, nonporous, and typically spherical silica particles in a liquid phase. The liquid is denser than water and has been stabilized electrostatically to allow the particles to stay suspended in the solution. There are many grades of colloidal silica, but all of them are composed of silica particles ranging in size from about 3 nm up to about 150 nm. These particles may be spherical or slightly irregular in shape, and they may be present as discrete particles or slightly structured aggregates. These particles may also be present in a narrow or wide particle size range - depending on the process in which they were created.
Silica sol as an applicable precursor could be used in lots of industrial applications, such as:
Used across the construction industry for increased durability and strength in concrete and cementing operations and ground consolidation.
Enabling precision, strength, safety and reliability in the foundry industry such as precision investment casting and refractory materials.
Creating nearly defect-free, flat surfaces on silicon semiconductor and sapphire wafers, and optical lenses.
Its application in coating industry includes decorative coatings, inorganic & insulation coatings, non-stick coatings, paper, inkjet & photo, pigment & fillers, plastic films, protective coatings, wood coatings are prolonging open-time, improving hardness and durability as well as improving anti-soiling properties.
• Other applications
In addition to stated applications, colloidal silica can be used in adhesives, beverage clarification, catalysts, cleaning products, textiles & fabrics, gel & AGM batteries and water treatment.
Particle size below 50 nm
colloidal concentration of silica is 11/2 Wt%.
The main advantage of nano silica is its high specific surface area in compared to micro silica which causes greater interactions in used environment. Silica particles are stabilized easily in nano-dimension which leads to formation more stable colloids.
Colloidal silica does not react with stainless steel or plastic materials. The use of mild steel or iron is discouraged to storage silica sol. Sols should be stored at 5-35 ºC (40-95 ºF). If the sol is subjected to freezing conditions, it can lose its stability and precipitate. Highly elevated temperatures may accelerate the growth of micro-organisms and/or decrease the long-term stability of the silica sol. You can choose from a variety of pumps with colloidal silica. It is recommended that all pumps are cleaned with water, and dried before and after use. For cleaning container, there are some helpful ways. The first way is flushing container with water by high-pressure hose. The second one is mixing the contents of container with a solution of 4-5% NaOH (heated in 50-60 ºC) by an agitator.
Since colloidal silica products consist of amorphous silica and water, they rank as one of the most environmentally-friendly, industrial chemical products. Colloidal silica does not usually present a problem. If you get colloidal silica in your eyes, rinse immediately with water. If problems persist, seek medical attention.
It should be noted that there are limited investigations on safety of nanoproducts because of their new history.
In general colloidal silica is not only available in bulk deliveries, but also in plastic drums and IBCs (Intermediate Bulk Container).
Standard Date : 2013/09/29
Expire Date : 2014/08/28