The Role of Colloidal Silica in Catalysts
The high purity and controlled particle size of LUDOX® colloidal silica make it an effective source of silica for zeolite synthesis. In other applications, LUDOX® colloidal silica functions to bind other catalyst components together.
LUDOX® colloidal silica is generally used in catalyst applications to:
- Provide the silica component of the catalyst support, zeolite, or molecular sieve
- Bind the components of the catalyst together
- Improve adhesion to substrates
- Improve physical properties (hardness, attrition resistance, etc.)
- Stabilize catalytic activity
With our unique proprietary particle growth and formulation expertise, Grace works with customers to develop solutions to deliver the right product characteristics for each application. And our committed R&D and technical support teams' comprehensive understanding of industry-specific processes and issues ensure you receive the maximum value from our products.
Silica Source for Zeolites
Zeolites are microporous aluminosilicate crystalline structures that contain channels or cavities that can selectively adsorb molecules based on their size and shape. A number of zeolite types are important in industrial-scale catalytic processes. LUDOX® colloidal silicas are a very useful source of silica, a key raw material for zeolite synthesis.
In this application, colloidal silica particles may be mostly dissolved or transformed in the presence of an alumina source to form the aluminosilicate or phosphoaluminosilicate zeolite. Our monomodal colloidal silicas have one of the most narrow particle size distributions in the industry. Conceptually, the narrow distribution enables more uniform reactivity.
Binder
LUDOX® colloidal silica functions to bind other catalyst components together, constituting a small percentage of the final catalyst. Chemically, surface silanol groups interact with either surface silanols of other silica particles or with surface metal hydroxides of other catalyst components.
With drying and calcination, water is eliminated via a condensation reaction so that stable Si-O-Si or Si-O-metal bonds are formed. As the reaction progresses, individual particles fuse together.
LUDOX® Silica Grade
|
Counterions
|
Nominal Particle Size (nm) |
Specific Surface Area (m2/g SiO2) |
Silica Content %SiO2 |
Typical Sodium Content (Wet Basis) %Na |
SM-AS |
NH4+ |
7 |
360 |
25 |
0.05 |
AS-30 |
12 |
230 |
30 |
0.06 |
|
AS-40 |
22 |
140 |
40 |
0.07 |
|
HSA |
H+ |
12 |
230 |
30 |
0.10 |
TMA |
22 |
130 |
34 |
0.10 |
|
FM |
|
5 |
435 |
15 |
0.30 |
SM |
Na+ |
7 |
360 |
30 |
0.50 |
LS |
12 |
230 |
30 |
0.10 |
|
HS-30 |
12 |
230 |
30 |
0.30 |
|
HS-40 |
12 |
230 |
40 |
0.40 |
|
TM-50 |
22 |
130 |
50 |
0.30 |