Microsilica, also known as silica fume or condensed silica fume, is a byproduct of large-scale industrial smelting. It is formed when highly volatile SiO2 and Si gases, generated in submerged arc furnaces, are emitted and rapidly oxidized, condensed, and precipitated by exposure to air. Due to its low density, specialized densification equipment is required for processing. The entire production process necessitates the use of dust removal and environmental protection equipment for recovery.

Fumed silica has an average particle size of 0.2 μm and a specific surface area ranging from 15,000 to 25,000 m²/kg. Its primary component is silicon dioxide, accounting for 85% to 95%, with impurities including metal oxides such as sodium oxide, calcium oxide, iron oxide, and aluminum oxide, as well as small amounts of elemental carbon and silicon. Due to the amorphous nature of silicon dioxide in fumed silica, which exhibits high reactivity, fine particles, and a large specific surface area, it possesses excellent physicochemical properties. Consequently, it is widely used in critical applications such as concrete, refractory materials, wall materials, cement products, mortar, flooring, and chemical industries for specialized engineering purposes.