Description
Wollastonite 325 Mesh Ceramic Grade
Wollastonite 325 Mesh Ceramic Grade (CAS 13983-17-0, molecular formula CaSiO3) is a raw material for tile, sanitaryware, tableware and refractory production, where particle size and impurity profile drive fired colour and body strength. China Chemicals supplies it at CaSiO3 95% min in pack sizes from 1 kg through to 1000 kg Bulk Bag, so laboratory trial quantities and full production volumes can be sourced from the same specification.
It is also traded as Calcium Metasilicate, Calcium Silicate, Tabular Spar. Every consignment ships with a batch-specific Certificate of Analysis and the current Safety Data Sheet, and material is stored and picked under stock rotation so you receive product well inside its shelf life.
Typical applications
- Fast-fire tile body enabling shorter kiln cycles
- Frit and glaze flux reducing firing shrinkage
- Asbestos-free reinforcement in friction materials
- Functional filler in paint and powder coating
- Reinforcement in engineering plastics
Technical specification
| Chemical name | Wollastonite 325 Mesh Ceramic Grade |
|---|---|
| Synonyms | Calcium Metasilicate, Calcium Silicate, Tabular Spar |
| CAS number | 13983-17-0 |
| Molecular formula | CaSiO3 |
| Appearance | White acicular powder |
| CaSiO3 | 95.0% min |
| CaO | 45 – 48% |
| SiO2 | 50 – 53% |
| Fe2O3 | 0.5% max |
| Aspect ratio | 8:1 – 15:1 |
| Loss on ignition | 2.0% max |
Values above are typical and are confirmed on the Certificate of Analysis issued against each batch. Tighter specifications can be quoted where a process requires them.
Packaging and supply
Available in 1 kg, 5 kg, 25 kg Bag, 1000 kg Bulk Bag. Bulk, road tanker and export drum quantities are quoted on request, including FOB and CIF terms for international shipment. Pricing shown is per pack in USD, exclusive of freight and any applicable duties.
Handling and safety
Transport classification: Not regulated · May cause respiratory irritation as dust. Store in the original closed container in a cool, well-ventilated area away from incompatible materials, and handle using appropriate personal protective equipment. Read the Safety Data Sheet in full before use — it is issued with every order and is available on request before purchase.
Supply to industry only. Products are sold for legitimate industrial, laboratory and manufacturing use. We may request end-use details and business registration before releasing an order.
What Is Wollastonite?
Wollastonite is a naturally occurring calcium silicate mineral (CaSiO3), theoretically 48.3% CaO and 51.7% SiO2, with a distinctive acicular (needle-shaped) crystal habit. Unlike most mineral fillers, which are roughly spherical or platy, wollastonite particles are elongated and act almost like short fibres. This gives wollastonite a dual function in ceramics: it contributes CaO as a flux, lowering the temperature needed to vitrify a ceramic body, while its fibrous structure provides reinforcement that measurably reduces crazing and cracking during firing and cooling.
Why Ceramic Producers Use Wollastonite
In wall and floor tile bodies, glazes and frits, wollastonite works as both a flux source and a crack-reduction aid. It permits faster firing cycles, and its low loss on ignition means less gas release during firing, which helps reduce glaze defects. It is often used alongside Talc Powder and Potash Feldspar in a balanced body or glaze recipe.
Other Applications
Beyond ceramics, wollastonite is used as a functional, reinforcing filler in paints and plastics, in bonds for vitrified grinding wheels, in electrical insulators, and as a replacement for asbestos in thermal insulation and friction products such as brake linings.
Handling & Safety
Wollastonite is a distinct, naturally occurring calcium silicate mineral and is not asbestos. As with any fine fibrous mineral powder, minimise dust inhalation with standard precautions: ventilation and a dust mask during bulk handling, plus eye protection.
Frequently Asked Questions
Why does wollastonite reduce crazing in ceramic glazes?
Its needle-like (acicular) crystal structure provides a reinforcing effect in the ceramic body and glaze layer. Combined with its flux action enabling lower firing temperatures, this reduces the thermal stress that causes crazing and cracking.
What does 325 mesh mean for wollastonite?
It refers to the particle size grade, material fine enough to pass a 325-mesh sieve, the standard fine grade used in tile bodies and glazes.
Is wollastonite the same as asbestos?
No. Wollastonite is a distinct, naturally occurring calcium silicate mineral, and is in fact used as a functional replacement for asbestos in some thermal and friction applications.
What other uses does wollastonite have besides ceramics?
Functional filler in paints and plastics, vitrified grinding wheel bonds, electrical insulators, and thermal and friction applications.
What packaging and order quantities are available?
We supply wollastonite in drums, bulk bags or loose bulk. Contact us for current pricing and lead time.
For further independent reference, see the Wikipedia entry on wollastonite, and browse our full Ceramic Chemicals range.
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