Silica fume is also called microsilica, silicon ash, condensed or densified silica fume, its color is grey.

Silica fume is also called microsilica, silicon ash, condensed or densified silica fume, its color is grey. This is a byproduct of producing silicon metal or ferrosilicon alloys, which is made in the furnace with quality quartz, coke and scrap iron.

Silica fume used in refractory can improve the liquidity and density, enhance the strength of high temperature and shock performance.

Silica fume high-strength concrete is easily to pour, long-term keep stability and higher strength, ect. It can improve the inner quality of the building, and widely used in the construction of bridges, water conservancy, and metro, ect. It is good modified material of concrete.

Items	Standard
SiO2	Min. 97.0%
C	Max. 0.7%
Fe2O3	Max. 0.1%
Al2O3	Max. 0.3%
CaO	Max. 0.3%
MgO	Max. 0.2%
K2O	Max. 0.3%
Na2O	Max. 0.2%
P2O5	Max. 0.1%
SO3	Max. 0.2%
CI	Max. 0.1%
Moisture	Max. 0.5%
Loss on Ignition	Max. 0.5%
Retained on 45um	Max. 0.5%
Bulk density	< 700 kg/m3

Silica fume can be supplied as your reuirements. 

Densified Silica fume/ Microsilica/silicon ash for concrete and refractory