Chemical Properties

Wollastonite is a valued source of chemically combined calcium oxide (CaO) and silica
(SiO2).  Its high CaO content gives it a natural, low temperature flux important in steel manufacturing.  This mineral is the preferred raw material source of CaO in ceramic glazes and frits.  Wollastonite’s alkaline nature acts as an anti-corrosive agent in paints and coatings.

Enhancing the surface chemistry of wollastonite is important in applications where it is used for reinforcement.  Coupling agents enable it to make a bond with a matrix that

• enhances mechanical properties,
• reduces shrinkage,
• increases weather resistance,
• improves surface properties, and
• reduces internal defects. 

Surface treated wollastonite permits higher filler loadings, improving dispersion, powder flow characteristics, and flow during mixing and molding in compounding systems. 

Click for Additional Reading on wollastonite's chemical properties in the Chemical Properties Overview (PDF).

Physical Properties

Wollastonite can cleave into fine fibers that have high aspect-ratio, which is important in applications requiring mechanical reinforcement.  Such products are used as functional reinforcements for thermoplastic and thermoset polymer compounds, as well as in cementitious systems.

The best wollastonite products are typically brilliant white in color with a silky or pearly lustre.  These physical traits are important in certain filler and ceramic applications. 

Wollastonite’s naturally high melting point is an asset in applications requiring high temperature stable reinforcement.   Its characteristically low coefficient of thermal expansion imparts high thermal shock resistance and dimensional stability in high temperature applications.  Wollastonite’s low thermal and electrical conductivity is an important attribute in many applications.

Click here for Additional Reading about wollastonite's physical properties in the Physical Properties Overview (PDF).