Natural Silica / Silicon Dioxide
What is Natural Silica / Silicon Dioxide ?
Silicon dioxide, also known as silica (from the Latin silex), is a chemical compound that is a dioxide of silicon with the chemical formula SiO2. It has been known since ancient times. Silica is most commonly found in nature as quartz, as well as in various living organisms, Silica is one of the most complex and most abundant families of materials, existing both as several minerals and being produced synthetically. Notable examples include fused quartz, crystal, fumed silica, silica gel, and aero gels. Applications range from structural materials to microelectronics to components used in the food industry.
In spite of its simple chemical formula, SiO2 , silica exists in many different forms. Silica is found commonly in the crystalline state but occurs also in an amorphous state resulting from weathering or plankton fossilisation. Silica exists in ten different crystalline forms or polymorphs, quartz being by far the most common. Quartz is the second most common mineral on the earth’s surface and it is found in almost every type of rock, i.e. igneous, metamorphic and sedimentary.
Silicon dioxide is obtained by mining and purification of the resulting mineral. Quartz comprises more than 10% by mass of the earth’s crust. Commercial silicon dioxide is also produced, almost always via the processing of quartz, synthetically on a very large scale. Since it is so abundant, quartz is present in nearly all mining operations. It occurs in the host rock, in the ore being mined, as well as in the soil and surface materials above the bedrock, which are called the overburden. Industry mainly uses the crystalline forms of silica, i.e. quartz and cristobalite.
A silica-based aero gel was used in the Stardust spacecraft to collect extraterrestrial particles. Silica is also used in the extraction of DNA and RNA due to its ability to bind to the nucleic acids under the presence of chaotropes. As hydrophobic silica it is used as a defoamer component. In hydrated form, it is used in toothpaste as a hard abrasive to remove tooth plaque.
In its capacity as a refractory, it is useful in fiber form as a high-temperature thermal protection fabric. In cosmetics, it is useful for its light-diffusing properties and natural absorbency. It is also used as a thermal enhancement compound in ground source heat pump industry.
High grade silica is normally found in unconsolidated deposits below thin layers of overburden. It is also found as ‘veins’ of quartz within other rocks and these veins can be
many meters thick. Silica sand deposits are normally exploited by quarrying and the material extracted may undergo considerable processing before sale. The objectives of processing are to reduce impurities and increase the grade of silica present and to produce the optimum size distribution of the product depending upon end use.
After processing the sand may be sold in the moist state or it may be dried. Dry grinding in rotary mills, using beach pebbles or alumina balls as grinding media is the most common way to produce silica and cristobalite flour. Since the natural resources of cristobalite are not sufficient for industrial use, it has to be synthesized by the conversion of quartz in a rotary kiln at high temperature (>1500°C) with the assistance of a catalyst.
It is Natural Silica [chemical formula is SiO2]. Also known as Silicon dioxide.
Synonyms of Silica includes fused quartz, crystal, fumed silica, silica gel, and Silicon dioxide.Silica properties:
An estimated 95% of silicon dioxide produced is consumed in the construction industry, e.g. for the production of cement. Silica is used primarily in the production of glass for windows, drinking glasses, beverage bottles, and many other uses. The majority of optical fibers for telecommunication are also made from silica. It is a primary raw material for many ceramics such as earthenware, stoneware, and porcelain. Silicon dioxide is also used to produce elemental silicon. The process involves carbothermic reduction in an electric arc furnace.This makes it a very essential mineral in our day-to-day life.
Silica is hard, chemically inert and has a high melting point because of the strength of the bonds between the atoms. These are prized qualities in various industrial uses. Quartz is usually colourless or white but is frequently coloured by impurities such as iron. Quartz may be transparent to translucent, hence its use in glassmaking, and has a vitreous lustre. Depending on how the silica sand was formed, quartz grains may be sharp and angular or rounded. For industrial use, pure deposits of silica capable of yielding products of at least 98% SiO2 are required.
Paints and Plastics, Polymer Compounds, Rubber, Sealants and Adhesives: Crystalline silica, as quartz and cristobalite, in its finest flour form is used as a reinforcing filler. Silica flour provides resistance against abrasive actions and chemical attack. Self-cleaning exterior wall coatings and heavy-duty offshore or marine paints are typical examples. The intrinsic properties of silica flour promote its use in plastics for encapsulating electronic components.
Silica Chemical Properties/Composition :
Silica Physical Properties :
|Appearance||: White free flowing powder|
|Oil absorption||: 25 to 35%|
|Sp. gravity||: 2.6-2.7|
|Refractive index||: 1.55|
|Loss on ignition||: 0.3% max|
|PH of 10% aqueous solution.||: 7 (neutral)|
Silica Industrial Applications & Uses :
- Glass & Pottery : Silica is used in bulk in glass industry, Ferro silicon, Ferro alloys, welding rods, pottery industries. It is also used in making silica Ferro manganese alloys. Silica is the major ingredient in virtually all types of glass. The principal glass products include containers (bottles and jars), flat glass (windows, mirrors, vehicle glass), tableware (drinking glasses, bowls, decanters), lighting glass (light bulbs, fluorescent tubes), TV tubes and screens (including flat screens), decorative glass optical glass, etc. The glass fibres, mainly used for composite reinforcing or in decorative textiles, are made from fine ground silica flour.
- Paints : In wood finish, primers, undercoats, water based paints, distemper, chemical resistance coating, floor coatings etc. It is recommended for texture coating and exterior finishes.
- Ceramics: Typical everyday products such as tableware, sanitaryware, ornaments and wall and floor tiles but also high tech ceramics contain silica flour that has been ground to fine sizes to form a major constituent of ceramic glazes. Crystalline silica is a main component in the production of refractory bricks, ladle linings and fluxes.
- Plastic & Rubber : Silica is used as a filler in plastic industry.
- Foundry Casting: Crystalline silica has a higher melting point than iron, copper and aluminium. This enables castings to be produced by pouring molten metal into moulds made out of silica sand and a binder. Castings form the basis of the engineering and manufacturing industries. Quartz and cristobalite flours are the main components in investment casting (also called precision casting) for the production of specialist products such as jewellery, dental bridges, aviation turbines and golf clubs.
- Filtration: Closely sized silica sand is the principal filtration medium used by the water industry to extract solids from waste water.
- Sports and Leisure: Silica sand is used for equestrian surfaces, including the production of all weather horse racing tracks. It is also used in the production of root zones and drainage media for high specification football and other sports pitches and for golf courses. It is also used in play sand pits for the construction of sand castles.
- Construction : Silica is also used in construction of Cement and chemicals for spray plasters. The construction industry is founded on silica sand and flours. There are a host of specialist applications including cement manufacture, silica and aerated concrete blocks, glues for roof and floor tiles, flooring and rendering compounds, white line markings, roofing felt and cement and resin injection systems.
- Oil field application: Special grades of silica sand that are of coarse size and have spherical particles are pumped down oil wells and into the oil-bearing strata to improve permeability and the flow of oil into the well.
- Agriculture: Silica is used in farming, market gardening, horticulture and forestry in applications such as soil conditioner or carrier for fertilizer and animal feed additives.
- Chemicals: Cristobalite sand and high purity quartz are used to produce a range of silicon chemicals including sodium silicate, silica gel, silicones, silicon tetrachloride, silanes and pure silicon. Pure silicon is used for silicon chips, the heart of the computer world. Silicon products are used in the production of detergents, pharmaceuticals and cosmetics.
- Metallurgical Industry: Quartz is the raw material for the production of silicon metal and ferrosilicon. Silicon metal is used in the production of alloys based on aluminium, copper and nickel. Ferrosilicon is a major alloying ingredient for iron and steel. Metal ores are purified in the furnace by silica sand that is transformed into metal slag.
- Food and pharmaceutical : Silica is a common additive in the production of foods, where it is used primarily as a flow agent in powdered foods, or to absorb water in hygroscopic applications. It is the primary component of diatomaceous earth. Colloidal silica is also used as a wine, beer, and juice fining agent. In pharmaceutical products, silica aids powder flow when tablets are formed.
Silica Price in India (Our suggested silica grades):
|Silica Grades / Model no.||VS – Nature||VS – Wash|
|Product Name||high purity natural silica sand||High quality Silica powder 200 mesh|
|Fe2O3 (%)||0.041||0.1 max.|
|CaO (%)||0.1 max.||0.02|
|All Sizes available*||200 mesh||200 mesh|
|Applications||Glass & pottery; paints; Rubber industry||Paints; Plastics; and Glass industry|
We have fine& high purity silica with very low Iron content.
|Packaging & Delivery Details:|
|Packaging:||50 kg pp bag; 1ton/bag; 1*20 container, can load 25-27 MT or upon clients’ requirement|
|Delivery:||within 5 – 20 days (depending upon the delivery location) after receiving the deposit|