Micro silica fume (scientific name "silica fume", English Name: microsilica or silica fume) is the industrial dust collected by a specially designed dust collector after the oxidation of silicon steam discharged from the flue when smelting ferrosilicon or industrial silicon, that is, amorphous and powdered silica (SiO2). The particle size of micro silicon powder monomer is 0.01 ~ 0.1 μ m, and the average particle size is 0.15 ~ 0.20 μ M. The specific surface area is between 15000-25000m2 / kg (measured by BET nitrogen adsorption method) and has strong surface activity.
Micro silica powder is in glassy state, mainly composed of amorphous silica. The rise of furnace gas also carries impurities, such as free C, Fe2O3, Cao, K2O, Na2O, etc.
The color of micro silica powder changes from white and gray to gray and dark gray with the increase of C and Fe2O3 content.
The micro silica powder for direct dust collection is called raw ash, and its bulk density is 130 ~ 180kg / m3. For the convenience of transportation and engineering application, the raw ash can also be densified. According to the different bulk density, the densified micro silica powder can be divided into semi densification (bulk density 320-400kg / m3) and full densification (bulk density 600-700kg / m3).