Production Process of Silica Fume (Microsilica)
Production Process of Silica Fume (Microsilica)
Production Process of Silica Fume (Microsilica)
1. Raw Materials & Smelting (Dust Generation)
Raw materials: Quartz sand (SiO₂) + coke (reducing agent) + iron ore (for ferrosilicon).
Equipment: Submerged arc furnace (1,700–2,000°C).
Reaction: SiO₂ is reduced by carbon, producing SiO vapor + small amounts of Si vapor; 10–15% of the silicon vapor escapes with the flue gas, oxidizes in air at the furnace mouth, and forms ultrafine amorphous SiO₂ dust (silica fume).
2. Flue Gas Treatment & Dust Collection (Core Stage)
Flue gas collection → cooling: Furnace hood → main duct → cooler (cooled to 200–250°C) to prevent bag burning and condensation.
Coarse dust removal (cyclone separator): Removes large particles and carbon residue to protect subsequent filter bags.
Fine dust collection (baghouse filter, mainstream):
Filter bags capture 0.01–1 μm ultrafine SiO₂ dust (silica fume).
Cleaning: Pulse jet / negative pressure reverse air; dust falls into hoppers.
Exhaust gas: Discharged after meeting emission standards (dust < 30 mg/m³).
3. Post‑Processing (Quality & Cost Optimization)
Homogenization: Blended in multiple silos to stabilize SiO₂ content (≥85–92%) and color.
Densification (key): Loose silica fume has a bulk density of only 150–200 kg/m³, leading to high transport costs; densified via densifier / gas‑phase compaction to 300–600 kg/m³, reducing freight by 30–60% and suppressing dust.
Packaging: Bulk (tanker) / bagged
