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    • Colloidal Silicon Dioxide CAS 7631-86-9

    Colloidal Silicon Dioxide CAS 7631-86-9

    Colloidal Silicon Dioxide (CAS 7631-86-9), commercially known as Fumed Silica or Pyrogenic Silica, is a submicroscopic fumed silica utilizing its immense surface area and porous structure to act as a premier glidant and suspension aid. Chemically identified as Amorphous Anhydrous Silicon Dioxide, this extremely light, fluffy white powder functions to reduce friction between particles, significantly improving the flow properties of dry powders in pharmaceutical tableting and food processing. As a highly thixotropic agent, it is extensively integrated into liquid systems (like paints, unsaturated polyester resins, and toothpaste) to provide anti-sagging and thickening control without altering the color or clarity. We ensure bulk supply capabilities for this material, providing access to competitive factory pricing and customized specifications to meet specific specific surface area (BET) requirements (e.g., 200 m²/g for standard hydrophilic grades). Full technical documentation, including MSDS, TDS, COA, is available to support compliance and safety protocols.

    • CAS: 7631-86-9
    • Synonyms: Fumed Silica, Pyrogenic Silica, Amorphous Silicon Dioxide, SiO2, Silica aerogel, Synthetic Amorphous Silica (SAS)
    • Einecs: 231-545-4
    • Molecular Formula: SiO2
    • Grade: Pharmaceutical Grade / Food Grade / Industrial Grade
    • Package: 10kg/Multi-layer paper bag (Due to low bulk density, standard packaging is 10kg, not 25kg).
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    Product Description

    Colloidal Silicon Dioxide is a sub-microscopic fumed silica with a particle size typically around 7-40 nm. It is an amorphous (non-crystalline) form of silicon dioxide.

    Core Functions:

    1. Flow Aid (Glidant): In pharmaceutical tablet manufacturing, it significantly improves the flow properties of powders, ensuring uniform dosage.
    2. Anti-Caking: Prevents clumping in hygroscopic powders and food products.
    3. Thickening & Thixotropy: In liquids (like creams, gels, and paints), it builds viscosity and prevents sagging or settling of pigments.
    4. Reinforcement: Used in silicone rubbers to increase tear strength and durability.
    1 Physicochemical Properties
    2 Applications
    3 Storage Conditions
    4 Safety Precautions

    Physicochemical Properties

    The specifications below refer to the standard Hydrophilic grade (comparable to Grade 200), widely used in general applications.

    ParameterSpecification (Standard)
    AppearanceFluffy white powder
    Specific Surface Area (BET)200 ± 25 m²/g
    Assay (SiO2)≥ 99.8% (on ignited basis)
    pH Value (4% dispersion)3.7 – 4.5
    Loss on Drying (105°C, 2h)≤ 1.5%
    Ignition Loss (1000°C, 2h)≤ 2.0%
    Tamped Density40 ~ 60 g/L
    Heavy Metals (Pb)≤ 20 ppm
    Arsenic (As)≤ 3 ppm
    Grit (Mils > 45µm)≤ 0.05%

    Applications

    1. Pharmaceuticals:
      • Glidant for tableting and capsule filling to improve powder flow.
      • Viscosity increasing agent in ointments and suppositories.
      • Suspension stabilizer in liquid medicines.
    2. Cosmetics & Personal Care:
      • Used in toothpaste as an abrasive and thickener.
      • Adds volume to hair styling powders.
      • Prevents caking in face powders and blushes.
    3. Food Industry:
      • Anti-caking agent for spices, powdered milk, and coffee creamers (E551).
    4. Industrial Uses:
      • Paints & Coatings: Prevents sagging and pigment settling.
      • Adhesives & Sealants: Provides thixotropic (non-drip) control.
      • Rubber: Reinforcing filler for silicone elastomers.

    For coating formulations that require a dedicated matting grade rather than a flow or anti-caking aid, see Silica Matting Agent.

    Storage Conditions

    • Moisture Sensitivity: This product is highly hygroscopic (absorbs moisture from the air).
    • Storage: Store in a cool, dry place. Keep pallets off the floor.
    • Sealing: Keep packaging tightly closed immediately after use to prevent moisture absorption which can affect flow properties.
    • Shelf Life: 24 months in unopened original packaging under dry conditions.

    Safety Precautions

    • Respiratory Protection: This powder is extremely fine and can become airborne easily (“dusty”). Always wear a NIOSH-approved dust mask or respirator (N95/P2) to avoid inhalation.
    • Ventilation: Use local exhaust ventilation.
    • Skin/Eye Contact: May cause mechanical irritation or drying of the skin. Wear safety goggles and gloves.
    • Health Note: This is amorphous silica, not crystalline silica. It does not cause silicosis, but long-term inhalation of high concentrations of any dust should be avoided.

    FAQ - Technical & Supply Chain

    • Q:

      What is Colloidal Silicon Dioxide CAS 7631-86-9?

      A: Colloidal Silicon Dioxide CAS 7631-86-9 is an amorphous, submicroscopic synthetic silica also known as fumed silica or pyrogenic silica. It has the molecular formula SiO2 and molecular weight 60.08 g/mol, and is supplied as a very low-density white powder.
    • Q:

      How does Colloidal Silicon Dioxide differ from precipitated silica?

      A: Colloidal or fumed silica is produced by flame hydrolysis and normally has a finer primary particle size, lower bulk density, and stronger glidant and thixotropic effects. Precipitated silica is made by a wet precipitation process from silicate solution and usually has different moisture content, bulk density, and handling behavior.
    • Q:

      Why is Colloidal Silicon Dioxide used in tablet manufacturing?

      A: It acts as a glidant and anti-caking agent, typically at 0.1% to 1.0%, to improve powder flow into tablet dies and support uniform weight. This helps reduce sticking, capping, and fill-weight variation during high-speed tableting.
    • Q:

      What food and industrial applications is this grade suitable for?

      A: Food-grade colloidal silicon dioxide is used as an anti-caking agent, carrier, and defoaming aid. Industrial grades are used in coatings, adhesives, paints, inks, and silicone rubber for thickening, thixotropy, anti-settling, and reinforcement.
    • Q:

      What key specifications should a buyer confirm for Colloidal Silicon Dioxide?

      A: The most important values are silica assay on an ignited basis, BET specific surface area, pH of an aqueous dispersion, loss on drying, loss on ignition, tapped density, and heavy-metal or arsenic limits. The standard hydrophilic grade in this product listing has a BET surface area around 200 m2/g.

    Ordering & Documentation

    Key information for document requests, quotations, and supply planning.

    Documents

    COA, TDS, SDS/MSDS and packing details are available on request.

    Quotation

    Send the CAS number, grade, quantity, packing preference and destination.

    Sample & Supply

    Support is available for samples, trial orders, bulk and repeat supply.

    Storage & Shipping

    Product-specific conditions are confirmed before order.

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