A few amazing silicon materials, what are their uses?
This article focuses on several materials related to silicon materials, which are very similar in shape, color and application. They have the same points and different places compared to silica fume. So in some cases you need to know how to distinguish them, even though they are similar.
Silica fume, also known as microsilica, is an amorphous (non-crystalline) polymorph of silicon dioxide, silica. It is an ultrafine powder collected as a by-product during silicon and ferrosilicon alloy production.
According to the bulk density, we can divide our products into densified silica fume and undensified silica fume.
High Performance Concrete (HPC) containing silica fume has been identified as one of the most important advanced materials necessary in the effort to rebuild the nation’s infrastructure. In addition to increased strength and enhanced durability, HPC produced with silica fume delivers increased toughness, increased resistance to abrasion, corrosion and chemicals, sustainability and life-cycle cost efficiencies.
Repair Products (Mortars & Grouts)
Silica fume is used in a variety of cementitious repair products. Mortars or grouts modified with silica fume can be tailored to perform in many different applications—overhead and vertical mortars benefit from silica fume’s ability to increase surface adhesion. Silica fume dramatically improves cohesiveness making it ideal for use in underwater grouts, decreases permeability in grouts used for post-tensioning applications and increases the resistance to aggressive chemicals.
Silica fume is used in refractory
The use of silica fume in refractory castables provides better particle packing. It allows for less water to be used while maintaining the same flow characteristics. It also promotes low temperature sintering and the formation of mullite in the matrix of the castable. This produces a castable that has a low permeability to avoid gas, slag and metal penetration.
Silica fume Shotcrete delivers greater economy, greater time savings and more efficient use of sprayed concrete. Silica fume produces superior shotcrete for use in rock stabilization, mine tunnel linings, and rehabilitation of deteriorating bridge and marine columns and piles. Greater bonding strength assures outstanding performance of both wet and dry process shotcreting with less rebound loss and thicker applications with each pass of the shotcrete nozzle.
Fumed silica, also known as fumed silica, is produced in flames. The resulting powder has an extremely low bulk density and a high surface area.
Its silica content is very high, reaching more than 99.8%, but its application range is different from silicon powder.
Fumed silica serves as a universal thickening agent and an anticaking agent (free-flow agent) in powders. Like silica gel, it serves as a desiccant. It is used in cosmetics for its light-diffusing properties. It is used as a light abrasive, in products like toothpaste. Other uses include filler in silicone elastomer and viscosity adjustment in paints, coatings, printing inks, adhesives and unsaturated polyester resins. It is also used in the production of cat litter box filler and as a core material in the production of vacuum insulated panels.
Metakaolin is the anhydrous calcined form of the clay mineral kaolinite. It is a product that is manufactured for use rather than a by-product and is formed when china clay, the mineral kaolin, is heated to a temperature between 600 and 800ºC.
The particle size of metakaolin is smaller than cementparticles, but not as fine as silica fume.It is very close to the application range of silica fume, so it is often compared with silica fume.
Considered to have twice the reactivity of most other pozzolans, metakaolin is a valuable admixture for concrete/cement applications. Replacing portland cement with 8–20% (by weight) metakaolin produces a concrete mix that exhibits favorable engineering properties, including: the filler effect, the acceleration of OPC hydration, and the pozzolanic reaction. The filler effect is immediate, while the effect of pozzolanic reaction occurs between 3 and 14 days.
Rice Husk Ash
Rice milling industry generates a lot of rice husk during milling of paddy which comes from the fields. This rice husk is mostly used as a fuel in the boilers for processing of paddy. Rice husk is also used as a fuel for power generation. Rice husk ash (RHA) is about 25% by weight of rice husk when burnt in boilers. It is estimated that about 70 million tones of RHA is produced annually worldwide. This RHA is a great environment threat causing damage to the land and the surrounding area in which it is dumped.
During milling of paddy about 78 % of weight is received as rice , broken rice and bran .Rest 22 % of the weight of paddy is received as husk . This husk is used as fuel in the rice mills to generate steam for the parboiling process . This husk contains about 75 % organic volatile matter and the balance 25 % of the weight of this husk is converted into ash during the firing process , is known as rice husk ash ( RHA ). This RHA in turn contains around 85 % – 90 % amorphous silica.
RHA is a carbon neutral green product. Lots of ways are being thought of for disposing them by making commercial use of this RHA. RHA is a good super-pozzolan . This super-pozzolan can be used in a big way to make special concrete mixes . There is a growing demand for fine amorphous silica in the production of special cement and concrete mixes ,high performance concrete , high strength, low permeability concrete, for use in bridges, marine environments , nuclear power plants etc.