Difference of silica fume, microsilica & white carbon black

Many friends know that white silica powder is commonly known as white carbon black. The main component of white carbon black is SiO2, which is named because it is white and its main physical properties and uses are similar to carbon black. The main components of today's micro silicon powder and white carbon black are silicon dioxide, but what are the differences and connections between their chemical properties?

SILICA FUME

① Appearance and basic chemical composition:

The appearance is gray or gray white powder, and the fire resistance is>1600 ℃. Unit weight: 1600~1700kg/m3. Chemical composition is as follows:

SiO2 content: 75~98%, Al2O3 content: 1.0 ± 0.2% , Fe2O3 content: 0.9 ± 0.3%

② Fineness and specific surface area:

Silica fume with medium fineness less than 1 μ M accounts for more than 80%, and the average particle size is 0.1~0.3 μ m. Specific surface area: 20-28m2/g. Its fineness and specific surface area are about 80-100 times of cement and 50-70 times of fly ash.

③ Particle shape and ore facies structure:

During the formation of silica fume, due to the effect of surface tension during phase transformation, amorphous spherical particles of amorphous phase are formed, and the surface is relatively smooth. Some are aggregates of multiple spherical particles stuck together. For materials mixed with silica fume, tiny spheroids can play a role in lubrication.

MICROSILICA POWDER 

① Appearance and basic chemical composition: the appearance is gray or gray white powder, and the fire resistance is>1600 ℃. Unit weight: 200-250kg/m3, the composition is as follows:

SiO2 content: ≥ 99.0%, Al2O3 content: ≤ 0.3%, Fe2O3 content: ≤ 0.02%

② Fineness and specific surface area: 200-5000 meshes, specific surface area: 20-28m2/g

WHITE CARBON BLACK 

① Appearance and basic chemical composition: a general term for white powdery X-ray amorphous silicic acid and silicate products, mainly referring to precipitated silica and fumed silica, which are porous substances, and their composition can be expressed by SiO2 · nH2O, in which nH2O exists in the form of surface hydroxyl. It is soluble in caustic soda and hydrofluoric acid, but insoluble in water, solvent and acid (except hydrofluoric acid). High temperature resistance, nonflammable, tasteless, odorless, and good electrical insulation. Melting point: 1610 ° C (lit.) Stacking density: 0.2g/ml (ordinary product by precipitation method)

Chemical composition: SiO2 (dry product ≥ 90%), Al2O3 content: ≤ 0.2%, Fe2O3 content: ≤ 0.1%

② Fineness and specific surface area: the fineness varies from 20-5000 meshes, and different fineness can be produced according to customer requirements. Specific surface area: white carbon black has an ultra-high specific surface area, generally 100-300 m2/g for precipitation method, and more than 400 m2/g for gas phase method.