Partic​le Size, Consistency, and Purity


Around the world, vehicle makers and other industries are responding to new environmental standards for emission controls. Grace is a global leader in highly pure colloidal silica used in various stages of emission control catalyst production including zeolite, washcoat, substrate, and canning applications.

Our highly pure LUDOX® monomodal colloidal silica products are designed to offer a consistent quality and narrow particle size distribution which gives the advantage that all particles will react at the roughly the same rate. These attributes make LUDOX® colloidal silicas an excellent choice for both mobile and stationary emission control applications.

LUDOX® colloidal silica helps improve catalytic performance.   As a binder, it provides excellent strength and adhesion in catalyst washcoats and catalyst structures. It also helps prevent degradation by providing thermal stability and as a low sodium silica source in the manufacture of zeolites. ​

Low Sodium Level

In many catalysts, sodium is a poison and must be minimized. While sodium silicate can be used to make some catalysts, its high sodium level (about 21% relative to silica) prevents its use in many others. LUDOX® colloidal silica products with sodium counter ions typically contain 0.5 – 2% Na relative to silica, depending on particle size, and products with ammonium ion typically contain 0.2%.  ​

Partnering with Grace​

When you choose LUDOX® colloidal silica, you choose the benefits of working with Grace. The LUDOX®  brand has been trusted for more than 30 years for its consistent quality, narrow particle size, and purity. Our expertise in silica - a material Grace has been innovating with for more than a century - is evident in the customer service and support we provide. More information about LUDOX® colloidal silica.

With our unique proprietary particle growth and formulation expertise, Grace partners 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.​​


LUDOX® COLLOIDAL SILICA - Recommended Grades


​Average Particle Size (nm)

​Specific Surface Area m2/g

​Silica Content %SiO2

​pH (25° C)

​Viscosity (25° C) cPs​








LUDOX® HS-30​12​220​30​9.7​4.1
LUDOX® HS-40​12​220​40​9.7​18
LUDOX® AS-30​12​220​30​9.4​20
LUDOX® HSA​12​22030​4.05.0
LUDOX® SK​12​220​254.0​​8.0
LUDOX® AS-40​22​135​40​9.2​11
LUDOX® TM-50​22​135​50​9.0​​40​