3/22/2023 0 Comments Silica formula![]() ![]() They may also be present in a narrow or wide particle size range, depending on the process in which they were created. The particles may be spherical or slightly irregular in shape, and may be present as discrete particles or slightly structured aggregates. There are many grades of colloidal silica, but all of them are composed of silica particles ranging in size from about 2 nm up to about 150 nm. Subtle differences in particle morphology, particle size, and ionic species can make all the difference.Ĭolloidal silica dispersions are fluid, low viscosity dispersions. Choosing the right colloidal silica can be a challenge. To give a couple of examples our products enhances the performance of waterborne coatings by delivering anti-soling properties as well as provides increased durability and strength in cementing operations. Where can colloidal silica be used?Ĭollodial silica can be used in numerous applications and it enhances functionality in an ever-growing number of products. Finally, the viscosity of sodium silicates is much higher - closer to that of a syrup, while colloidal silicas have viscosities close to that of water. Sodium silicates are also composed of silicate monomers, as opposed to colloidal silica composed of polymeric silicates.The composition of sodium silicates have a SiO 2/Na 2O ratio of approximately 3.4, whereas colloidal silica generally has a SiO 2/Na 2O ratio greater than 50. Sodium silicates are alkaline solutions with pH ranges of 12-13, compared to 9-11 for colloidal silica. This random distribution is what makes amorphous silica different from crystalline silica - ordered on a molecular level. What's the difference between sodium silicate (water glass) and colloidal silica?Ĭolloidal silica consists of dense, amorphous particles of SiO 2.The building blocks of these particles are randomly-distributed -tetrahedra. The term nano silica can also have a wider definition and include other types of silica in powder form. Within the construction industry aqueous dispersions of colloidal silica are also referred to as nano silica and used for example in geotechnical, shotcrete and other concrete applications. In addition, it has the widest ranging surface area, and its aggregate size can be as small as the actual size of the primary particle. The most noticeable difference is that it's in liquid form, as opposed to powder. How does colloidal silica differ from fumed, fused, or precipitated silica?Ĭolloidal silica varies from other types of silica in several significant ways. Particle sizes range from about 1 to 100 nm. What does "colloidal" mean?Ī colloid is a stable dispersion of particles - particles that are small enough that gravity doesn't cause them to settle, but large enough not to pass through a membrane and allow other molecules and ions to pass freely. Amorphous silica, on the other hand, is industrially manufactured in a variety of forms - including silica gels, precipitated silica, fumed silica, and colloidal silica. It can be found in nature in crystalline form (as quartz sand), and it is the most abundant component of the earth's crust. ![]() Silica is another name for silicon oxides - the most prevalent type being SiO 2. Present technology would be very different without the silica used to create the catalysts of our oil refineries, bind the molds for casting super-alloys, form modern glass and ceramics, and polish electronic materials. Two-thousand year-old Roman cement contains amorphous silica from volcanic ash which helps give it high strength and durability. Flint is a form of silica that was used in ancient tools.The sand used in pottery is also a form of silica. Not only does silica play an important role in biology, it had played an important role in civilization. The role of silica is less obvious in animals, but each one of us contains about half a gram of silica – without which our bones, hair, and teeth could not be formed. Many plants use silica to stiffen stems for holding fruit and to form external needles for protection. Diatoms, a type of phytoplankton forming the base of the ocean’s food chain, have skeletons composed of silica. The semi-precious mineral opal is a form of amorphous silica that has been prized for centuries.īesides being the most abundant mineral on the Earth, it is also very important to life on our planet. It is present in not only in combination with other oxide minerals but also in its isolated forms such as sand. Of all the oxide minerals in the Earth’s crust, silicon dioxide, or silica, is the most abundant. ![]()
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