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Silica Fume (Microsilica)

High-activity pozzolanic mineral admixture, SiO₂ content ≥85%-96%, suitable for high-performance concrete, shotcrete, refractories and more.

$38 - $343 / MT (FOB)

SiO₂ Content≥85% - 96%
Specific Surface Area15000-25000 m²/kg
Packaging25kg / 500kg / 1000kg
Delivery Time3-7 days in stock

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Choose Your Silica Fume Grade

Three distinct grades engineered for different applications. Click any grade below for full technical data, pricing and FAQ.

PREMIUM

White Silica Fume

95% Zircon (ZrO₂ 3%-5%) for refractories | 98% White for UHPC & decorative concrete. Whiteness ≥90%.

From $420/MT View Details →

HIGH ACTIVITY

92% Black Silica Fume

SiO₂ ≥92%, high pozzolanic activity, excellent cost-performance for C40-C70 concrete, grout, shotcrete & oil well cementing.

From $55/MT View Details →

FULL RANGE

Gray Silica Fume (85%-95%)

Full-grade coverage from economical 85% to high-activity 95%. Ideal for high-strength concrete, precast, bridges & marine structures.

From $42/MT View Details →

Product Overview

Silica Fume (Microsilica) is an ultra-fine amorphous silica powder collected from flue gases during the production of ferrosilicon alloys and industrial silicon. Our silica fume has SiO₂ content ≥85%-96% and specific surface area of 15000-25000m²/kg, featuring ultra-high pozzolanic activity and micro-filler effect that significantly improve concrete strength, density and durability. Compliant with ASTM C1240, EN 13263, GB/T 27690 standards, widely used in high-performance concrete, shotcrete, refractories, self-leveling mortars, exported to 50+ countries.

Technical Specifications

Parameter	Specification
SiO₂ Content	≥85% / 90% / 92% / 95% / 96%
Loss on Ignition	≤4.0%
Moisture Content	≤3.0%
Specific Surface Area	15000-25000 m²/kg
Activity Index	≥85% (28 days)
Chloride Ion Content	≤0.1%
Fineness (45μm Sieve Residue)	≤5% / 10%
Density	2.1-2.3 g/cm³

Product Features

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Ultra-High Pozzolanic Activity

Amorphous SiO₂ in silica fume rapidly reacts with Ca(OH)₂ from cement hydration to form C-S-H gel, significantly improving concrete later strength and density.

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Micro-Filler Effect

Silica fume particle size is only 1/100-1/50 of cement particles, effectively filling gaps between cement particles, optimizing particle grading and reducing concrete porosity.

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Significantly Improved Durability

Greatly improves concrete resistance to chloride ion penetration, freeze-thaw, sulfate attack, alkali-aggregate reaction, extending structural service life.

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Early Strength Enhancement

Adding silica fume significantly improves concrete 1-3 day early strength, accelerating formwork turnover and construction efficiency.

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Improved Workability & Bleeding

Spherical particle morphology of silica fume provides ball-bearing lubrication, effectively reducing concrete bleeding and segregation, improving construction workability.

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Internationally Certified Quality

ISO 9001 certified, compliant with ASTM C1240, EN 13263 international standards, COA test report provided for each batch.

Applications

High-Performance Concrete (HPC/UHPC)

C80-C150 high-strength concrete, ultra-high performance concrete for high-rise buildings, bridges, marine engineering.

Shotcrete

Shotcrete for tunnels, mines, slope support, increasing single-layer thickness and reducing rebound.

Refractories

Unshaped refractories, castables, plastics, improving high-temperature strength and thermal shock resistance.

Self-Leveling Mortar & Grout

Improves mortar fluidity, density and early strength.

Wear-Resistant Flooring & Repair Mortar

Improves floor wear resistance, impact resistance and bond strength.

Oil Well Cementing

Improves density and corrosion resistance of cement stone in oil well cementing.

Packaging & Logistics

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Packaging

25kg/bag (laminated woven bag with PE liner), 500kg/bag, 1000kg/bag (jumbo bag)

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Container Loading

20ft container: 20-22MT (jumbo bags), 24MT (25kg bags)

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Transportation

Sea freight, rail transport, truck transport

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Delivery Time

In-stock: 7 days; custom: 15-20 days

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Payment Terms

T/T (30% deposit, 70% against B/L copy), L/C, PayPal (samples)

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Export Markets

Exported to Southeast Asia, Middle East, EU, Latin America, Africa, 50+ countries

Quality Assurance

✓

Each batch undergoes strict testing before shipment, COA quality report provided

✓

ISO 9001 quality management system certified

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Compliant with ASTM C1240, EN 13263, GB/T 27690 international and domestic standards

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Customized specifications available based on customer requirements

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Professional laboratory equipped with full testing equipment to ensure stable and reliable product quality

FAQ

Are silica fume and microsilica the same product? +

Yes, silica fume and microsilica are different names for the same product - ultra-fine silica powder collected from ferrosilicon alloy smelting flue gases.

What is the recommended dosage of silica fume? +

Generally recommended dosage is 5%-10% of total cementitious materials. Specific dosage should be determined by testing based on concrete strength grade, construction process and durability requirements.

Does silica fume need to be mixed with water? +

Silica fume can be directly added to concrete in dry powder form and mixed with cement and aggregates. It can also be made into silica fume slurry (water-cement ratio 1:1-1:2) for better dispersion.

Can you provide samples? +

Yes, we provide free 1-2kg samples for customer testing. Sample shipping cost is borne by the customer.

What is the minimum order quantity? +

Minimum order quantity for standard products is 1 ton. Small trial orders are supported.

Silica Fume (Microsilica)