What Is Wollastonite?
Wollastonite is a little-known but extremely useful calcium-silicate mineral (CaSiO3) created when impure limestone, often in the presence of silica-bearing metamorphic rock, is subjected to high temperature and pressure. It is a relatively rarely-occurring mineral and is produced in a few places worldwide with only 3 mines in North America offering the product. It is a bright white mineral with a pearly luster on cleavage surfaces and a granular texture. With a Mohs hardness between 4.5 and 5, it is also a relatively soft mineral and splinters unevenly when fractured. Wollastonite has a wide range of uses thanks to a unique chemical makeup, mineralogical structure and physical characteristics. The following is a list of current applications:
Environmental Rehabilitation
The various chemical properties of wollastonite make it a very useful mineral in the treatment of bodies of water via heavy metal remediation, phosphorus adsorption and pH balancing. Other uses include mineralogical carbon sequestration and reclaiming forests damaged by acid rain. The mineral can also be used as a non-chemical grub control when mixed into pesticide-prone growing media.
A High-Performance Aggregate
Construction Wollastonite is a safe replacement for asbestos and fireproofing applications. This unique multi-purpose white mineral is also used as a functional additive to improve the flexural and impact strength of concrete.
Metallurgy Desirable fluxing properties make wollastonite useful as a flux for welding, a slag conditioner and an oxidation barrier during continuous casting of steel. Cost savings come from the lower temperatures required during smelting and the reduction in CO2 released.
Unique Counters and Tiles
Wollastonite is used in fire-resistant building products and performs well when used in countertop and tile applications.
Enhancing Food Production
Wollastonite in soil provides a source of plant-available silicon and carbon neutral calcium, unlike lime which releases ~30% of its weight as CO2 when it reacts with soil. It can also be used in livestock applications as a natural insecticide, traction additive, and pH balancer in stockyard surfaces. Learn more about Wollastonite Applications