LUDOX® Colloidal Silicas in Refractory Insulation
LUDOX® colloidal silica particles are routinely used as inorganic flocculants, binders, and stiffeners for refractory fibers to produce high-temperature composites in diverse applications.
- Sheeting and Block
- Appliance insulation
- Furnace and duct liners
- Expansion joint packing
- Cooking counters
- Catalytic converter insulation
- Papers and Felts
- Portable flange covers
- Wrapping insulation
- Gasket separators
- Special Shapes
- Heating element support for cooking counters
- Ladle liners
- Tap-out plugs
- Metal transfer
- Hot-top liners
- Combustion chambers
- Riser sleeves for metal casting
Depending on your application and its potential in the marketplace, Grace can help you select or even customize the particle size and chemistry to make your idea work, or work better.
Why LUDOX® Colloidal Silicas?
LUDOX® colloidal silicas are ideal inorganic binders and strengtheners due to their heat resistance, high purity, small size, high surface charge, and surface reactivity.
The properties of refractory composites can be modified by varying the type and amount of fiber and binder, changing the fabrication process, or adding post-treatments and specialty coatings. Manufacturing bonded refractory composites with LUDOX® colloidal silicas imparts many advantages:
- Low density
- Resistance to thermal shock
- Low thermal expansion
- Resiliency
- Resistance to mechanical shock and vibration
- Flexibility in control of product properties
- High-temperature tolerance (up to 1,650°C/3,000°F)
LUDOX® Colloidal Silicas Commonly Used in Refractory Applications
Property |
SM |
HS-40 |
TM-50 |
AS-40 |
TMA |
Counterion |
Sodium |
Sodium |
Sodium |
Ammonium |
- |
Silica (as Si02), wt. % |
30 |
40 |
50 |
40 |
34 |
Si02/Na20, wt. % |
50 |
95 |
225 |
- |
- |
Nominal Particle Size, nm |
7 |
12 |
22 |
22 |
22 |
Surface Area, m2/g |
360 |
230 |
130 |
140 |
130 |
pH (25˚C/77˚F) |
10.0 |
9.5 |
9 |
9.3 |
7.0 max |
Surface Charge |
Negative |
Negative |
Negative |
Negative |
Negative |