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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