Composition and Chemical Properties
Silica fume is 85–95% of a type of silicon dioxide called amorphous. It also contains amounts of other materials like aluminum oxide, iron oxide, calcium oxide, and some carbon. It is made in furnaces as particles. These particles are collected using filters.
Why Industries Use It
Silica Fume is used because it makes concrete into a special type that is strong, long-lasting, and not easy to damage.
- Makes concrete much stronger both when it first hardens and over time
- Helps keep water and harmful chemicals out of the concrete
- Protects the steel inside from rusting
- Helps concrete last longer in tough places like cold areas or under a lot of pressure
- Helps concrete stick better when it is sprayed on surfaces or used in repair work
- Helps make very strong concrete for big buildings, bridges, and underwater areas
Major Industrial Uses
1. High-Strength Concrete for Infrastructure
- Used in buildings, long bridges, tunnels, and areas near the sea where it needs to be very strong and last a long time
- Can reach 70–100+ MPa strength with the right mix
- Makes structures smaller and lighter without losing strength
2. Marine and Coastal Structures
- Used for docks, walls, and underwater parts of buildings that are exposed to salt and chemicals
- Helps keep salt from getting into the concrete and rusting the steel
- Resists damage from salt water and other harsh conditions
3. Sprayed Concrete and Underground
- Helps the concrete stay together better and not fall off when it is sprayed on tunnels, mines, and hills
- Sticks well to rock and old parts of buildings
- Helps make the work cleaner and easier to do
4. Fixing Concrete and Filling Gaps
- Used to fix parts of buildings, hold things in place, and fill gaps where it needs to stick well and not let water in
- Helps stick to old concrete and metal parts
- Lasts a long time in places with tough chemicals
Checking the Quality of Silica Fume
When buying Silica Fume for concrete, check the following to make sure it is good:
- SiO₂ Content: At least 85% (standard); at least 92–94% (for special uses)
- Specific Surface Area: 15,000–25,000 m²/kg for best results
- Particle Size: Around 0.1–0.3 micrometers; a small range for good performance
- Bulk Density: 300–650 kg/m³ (pressed for ready-made concrete); 180 kg/m³ (not pressed for spraying and heat parts)
- Loss on Ignition (LOI): Less than 5% (low carbon and other stuff)
- Chloride Content: Less than 0.02% (from silicon metal); less than 0.5% (from ferrosilicon) to keep steel from rusting
- Color: Light to dark gray (same in each batch); white types are available for nice-looking buildings
- Moisture Content: Less than 1% to keep the powder from clumping and to make it easy to use
Always ask for a test report and safety information from the company you buy from.
Leading Manufacturers of Silica Fume
- Elkem Materials (Norway/USA)
- Ferroglobe (Spain/USA)
- CNPC (China)
- Simcoa Operations (Australia)
- RSI (USA)
- Hengrui Silicon Industry (China)
- FerroAtlantica (Spain)
- DowSil (USA)
- Jinyu Silicon Industry (China)
- Ferro Alloy (China)
Where to Buy Silica Fume in Pakistan?
If you want to purchase Silica Fume in Pakistan, it is readily available in the market. Some places to buy Silica Fume in cities in Pakistan include:
- Lahore – Shah Alam Market chemical shops.
- Karachi – Jodia Bazaar chemical dealers.
- Faisalabad – Textile area industrial clients.
Other large cities (Multan, Sialkot, Gujranwala, Rawalpindi, Islamabad, Peshawar, Quetta). Silica Fume is available in 25 kg HDPE packing or jumbo packing for orders.
Price Overview (Pakistan – 2026)
Prices may vary based on purity level, grade, and import source.
- China Bulk Export (2026) – $250–$450/ton
- Pakistan Local Market – PKR 80–150/kg
Tianjin Unilion can manage every step of the process for clients who need help importing Silica Fume and other industrial chemicals, from sourcing and procurement to logistics, customs clearance, and timely delivery.
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