Precipitated Silicon Dioxide Supplier Price
Precipitated Silicon Dioxide Supplier – Technical Overview and Pricing
Precipitated silicon dioxide, also known as fumed silica, is an amorphous form of SiO₂ produced by vapor‑phase hydrolysis of silicon tetrachloride in an oxy‑hydrogen flame. The resulting primary particles aggregate into a three‑dimensional network that imparts high surface area, typically ranging from 100 to 400 m²/g, and low bulk density, often between 30 and 80 kg/m³. These structural characteristics determine its performance as a thickening agent, anti‑settling additive, and reinforcing filler in polymers, coatings, adhesives, and silicone rubber.
Key Material Properties
The product is supplied as a white, free‑flowing powder with a moisture content usually below 0.5 % by weight, measured after drying at 105 °C for 2 hours. Particle size distribution is governed by the agglomeration state; primary particle diameter lies in the 5–50 nm range, while secondary aggregates can reach several micrometres, influencing rheological behavior in liquid systems.
| Property | Typical Range | Test Method |
|---|---|---|
| Specific Surface Area (BET) | 100–400 m²/g | ASTM D3663 |
| Loss on Drying (105 °C, 2 h) | ≤0.5 % | ISO 787-2 |
| pH (5 % slurry) | 3.5–4.5 | ISO 787-9 |
| Tamped Density | 30–80 kg/m³ | ASTM D1208 |
Manufacturing Considerations
Production occurs in a continuous flame reactor where SiCl₄ vapor reacts with hydrogen and oxygen at temperatures exceeding 1 500 °C. The rapid nucleation and subsequent aggregation are controlled by flame temperature, residence time, and feed rate, allowing tailoring of surface area and aggregate size. Post‑treatment steps such as hydrophobic silylation can be applied to modify polarity for specific polymer compatibility.
Typical Industrial Applications
In silicone rubber, precipitated silica functions as a reinforcing filler that improves tear strength and abrasion resistance without significantly increasing viscosity. In coatings and inks, it acts as a thixotropic agent, preventing pigment settling while allowing easy application under shear. Adhesive formulations benefit from its ability to increase bond strength and reduce sag. The material is also used as a carrier for catalysts and as an anti‑caking agent in powdered food additives, where its inertness and high surface area are critical.
- Silicone elastomers – reinforcement, tensile strength improvement
- Paints & coatings – thixotropy, anti‑settling
- Adhesives & sealants – viscosity control, cohesion
- Pharmaceuticals – glidant, flow aid
- Food processing – anti‑caking, carrier
Quality Assurance & Testing
Each batch undergoes a standardized test program that includes BET surface area measurement, loss on drying, pH determination, and tamped density. Trace metal analysis (Fe, Al, Ca) is performed via ICP‑OES to ensure levels remain below typical specification limits (< 10 ppm). Hydrophobicity grades are verified by contact angle measurement on polished silica plates. All testing follows ISO/IEC 17025 accredited procedures, and certificates of analysis are provided with every shipment.
Pricing Factors
The price of precipitated silicon dioxide is influenced by several technical variables: specific surface area, degree of hydrophobicity, aggregate size distribution, and purity level. Higher surface area grades, which require tighter flame control and longer residence times, generally command a premium. Hydrophobic treatments add cost due to the additional silylation step and subsequent quality verification. Volume discounts are typical for orders exceeding 5 tonnes, while custom particle size specifications may involve setup fees and longer lead times.
| Grade | Surface Area (m²/g) | Hydrophobicity (Contact Angle, °) | Typical Price Indicator (USD/kg) |
|---|---|---|---|
| Standard Hydrophilic | 200 | ≤10 | 2.5–3.5 |
| Medium Hydrophobic | 180 | 90–100 | 3.0–4.0 |
| High Hydrophobic, Low Density | 150 | 110–120 | 3.5–4.5 |
All prices are indicative and subject to change based on raw material costs, energy prices, and contract terms. Exact quotations require clarification of required surface area, treatment type, packaging, and delivery location.
Ordering and Technical Support
To obtain a formal quotation, provide the following details: target surface area or grade, hydrophobic or hydrophilic finish, required quantity (kg or tonnes), preferred packaging (multi‑wall paper bags, bulk bags, or drums), and destination port or facility. Our technical team can recommend suitable grades based on your formulation constraints and supply samples for evaluation upon request.