Silica fume

Silica fume, as the by-product of metallic silicon production, is collected and processed by a special trapping device from the soot that escapes with the exhaust gases in the process of melting industrial silicon and ferrosilicon in industrial electric furnaces at high temperatures.

As a new raw material, silica fume is commonly used in concrete, oil well, mortar and refractory castable. Silica fume can fill the pores between cement particles, and at the same time generate gel with hydration products and react with alkaline material MgO to generate gel. Mixing appropriate amount of silica fume can significantly improve the performance of concrete, in particular its compressive strength, bond strength, and abrasion resistance. Addition of silica fume also reduces the permeability of concrete to chloride ions, which protects the reinforcing steel of concrete from corrosion, especially in chloride-rich environments such as coastal regions and those of humid continental roadways and runways (because of the use of deicing salts) and saltwater bridges.

With stable PH and low impurity level, Silica fume is perfectly adapted to the requirements of refractory castables. It enhances the flowability, hot strength and durability of refractory materials.

Usually the density of silica fume used in refractory materials is around 0.28-0.40 tonne/m3 and in concrete is around 0.55-0.70 tonne/m3, and it is usually transported in tonnage bags. The product is produced according to ASTM C1240-20 Standard Specification for Silica Fume Used in Cementitious Mixtures.