Silica fume
Silica fume
Grade:
English name: Microsilica or Silica fume
English alias: Microsilica锛孎umes, silica; AMORPHOUS SILICA FUME; Silica, amorphous - Fume total dust;Silica, amorphous - Fume, respirable; silica welding fumes
Molecular formula: SiO2
CAS No.: 69012-64-2
EINECS: 273-761-1
Relative density (water=1): 2.65g/cm3
Melting point: 1750鈩
Appearance: Gray or off-white powder
Performance: good temperature resistance, acid and alkali corrosion resistance, high thermal conductivity, high insulation, low expansion, stable chemical properties, high hardness and other excellent performance
Fineness: micro-silica powder fineness less than 1μm accounted for more than 80%, the average particle size in 0.1 ~ 0.3μm, specific surface area: 20 ~ 28m2/g. Its fineness and specific surface area is about 80 ~ 100 times that of cement, 50 ~ 70 times that of fly ash.
| Item | SiO2 | Al2O3 | Fe2O3 | MgO | CaO | Na2O | PH |
| Data | 75~98% | 1.0±0.2% | 0.9±0.3% | 0.7±0.1% | 0.3±0.1% | 1.3±0.2% | neutral |
It is widely used in chemical, electronic, integrated circuit (IC), electric appliance, plastic, paint, advanced paint, rubber, national defense and other fields.
Microsilica powder can fill the pores between cement particles, while generating gel with hydration products and reacting with alkaline material magnesium oxide to generate gel. In cement-based concrete, mortar and refractory casting materials, mixing the right amount of silica fume can play the following roles:
1銆丼ignificantly improve the compressive, flexural, seepage resistance, corrosion resistance, impact resistance and wear resistance.
2銆両t has the function of water retention, preventing segregation, water secretion and significantly reducing the pumping resistance of concrete.
3銆丼ignificantly prolong the service life of concrete. Especially in harsh environments such as chlorine salt pollution erosion, sulfate erosion and high humidity, the durability of concrete can be doubled or even multiplied.
4銆丼ignificantly reduce the landing ash of sprayed concrete and casting material, and increase the thickness of single spray layer.
5銆両t is a necessary ingredient of high-strength concrete, and there are already engineering applications of C150 concrete.
6銆両t has about 5 times the effect of cement, and can be used in ordinary concrete and low cement castables to reduce costs. Improve durability.
7銆丒ffectively prevent the occurrence of concrete alkali aggregate reaction.
8銆両mprove the denseness of castable refractories. When coexisting with Al2O3, it is easier to generate mullite phase, which enhances its high temperature strength and thermal vibration resistance.
9銆乄ith strong volcanic ash effect, when mixing concrete, it can have secondary hydration reaction with cement hydration product Ca(OH)2, forming cementitious products, filling cementite structure, improving the microstructure of slurry, and improving the mechanical properties and durability of hardened body.
10銆丮icro-silica powder is amorphous spherical particles, which can improve the rheological properties of concrete.
11銆乀he average particle size of microsilica powder is relatively small, which has good filling effect and can fill in between the cement particle gaps to improve the strength and durability of concrete.
High quality microsilica powder is mainly used as high performance refractory castables, prefabricated parts, ladle materials, breathable bricks, self-flowing refractory castables and dry and wet injection materials. In the field of high temperature ceramics, such as: oxide bonded silicon carbide products, high temperature type calcium silicate light insulation materials, corundum mullite pushing plate for electromagnetic kilns, high temperature wear resistant materials and products, corundum and ceramic products, selon bonded products, etc., micro silica powder is used with high fluidity, low water storage, high density and high strength.
Micro-silica powder is blended with water to make pellets and then dried or sintered naturally without adding binder, and the pellets have few impurities and can be returned to the electric furnace as smelting material.
In order to prevent some chemical synthetic powder from caking, micro-silica powder can be used to replace the more expensive treatment materials, instead of partial dispersion isolation and or increase the effect, widely used in micro-fine pesticides, fertilizers, fire extinguishing agents and other products.
The product should be stored in a dry, rain-sheltered, shaded environment. The product encounters water caking activity loss. Prohibit prolonged exposure to the sun to avoid weathering of the bag and spilling of the product outside.
