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.

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​