Wollastonite CAL
Grade
CAL = calcined / high-brightness ceramic grade
Use for wall tile, sanitaryware and low-loss electrical ceramic bodies needing minimum LOI, low iron and high whiteness for fast firing.
Values for the CAL condition
Other Wollastonite tempers and conditions
Wollastonite is listed in 4 conditions; see the grade overview at Wollastonite.
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
ACICDefault Acicular high-aspect-ratio powder | Default general-purpose grade: needle-like particles (aspect ratio ~15:1–20:1) for reinforcing ceramics, plastics, coatings and friction materials. | — | 350 | 0.1 | 380 HV | 3 W/m·K |
Solution annealed | Choose for polymer compounds (PA, PP, PBT, phenolic) where coupling agent is needed for strength, impact and low moisture pickup. | — | 350 | 0.3 | 380 HV | 2 W/m·K |
Finely milled blocky powder | Pick when low viscosity, high loading and smooth surface finish matter more than reinforcement (paints, sanitaryware bodies, glazes, adhesives). | — | — | 0.1 | 380 HV | 3 W/m·K |
CALThis page Calcined / high-brightness ceramic grade | Use for wall tile, sanitaryware and low-loss electrical ceramic bodies needing minimum LOI, low iron and high whiteness for fast firing. | — | — | 0.1 | 400 HV | 3 W/m·K |
What is Wollastonite CAL?
Wollastonite CAL is Wollastonite in the CAL grade — use for wall tile, sanitaryware and low-loss electrical ceramic bodies needing minimum LOI, low iron and high whiteness for fast firing. Wollastonite CAL has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. Elongation at break is 0.1% and the elastic modulus is 115 GPa (16.7 Msi). Wollastonite CAL has a density of 2.9 g/cm³ (0.105 lb/in³), lighter than 76% of ceramic grades. It melts at 1,540°C (2,804 °F). ACIC is the default condition FabDigit quotes; CAL is available on request or by drawing note.
Advantages
- Low embodied carbon — 0.12 kg CO₂/kg, better than 100% of ceramic grades
- Easy to machine — 42/100, better than 86% of ceramic grades
- Lightweight — 2.9 g/cm³ (0.105 lb/in³), better than 76% of ceramic grades
Limitations
- Needs corrosion protection — 45/100, worse than 90% of ceramic grades
- Poor heat conductor — 2.6 W/m·K (1.5 BTU/hr·ft·°F), worse than 80% of ceramic grades
Wollastonite CAL properties
Typical room-temperature values for Wollastonite CAL; 15 are specific to this condition. Other listed values are Wollastonite reference data and may not represent this condition. Bars are the position among ceramic grades.
Physical3
Wollastonite CAL has a density of 2.9 g/cm³ (0.105 lb/in³), lighter than 76% of ceramic grades. It melts at 1,540°C (2,804 °F).
Mechanical12
Wollastonite CAL has a tensile strength of 350 MPa (50.8 ksi), stronger than 71% of ceramic grades. Elongation at break is 0.1% and the elastic modulus is 115 GPa (16.7 Msi).
Thermal5
Wollastonite CAL is rated for continuous service to 1,100°C (2,012 °F). It conducts heat at 2.6 W/m·K (1.5 BTU/hr·ft·°F), worse than 80% of ceramic grades. Thermal expansion is 6.5 µm/m·K (3.61 µin/in·°F).
Electrical4
Wollastonite CAL has an electrical resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
Corrosion resistance is fair (45/100), worse than 90% of ceramic grades.
Sustainability4
Producing a kilogram of Wollastonite CAL takes about 2 MJ of energy and emits 0.12 kg of CO₂ — less than 100% of ceramic grades. Typical recycled content is 0%.
Manufacturability1
Wollastonite CAL's machinability is fair (42/100, better than 86% of ceramic grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Wollastonite CAL
Is Wollastonite easy to machine?
Fired wollastonite bodies are green-machinable before firing and require diamond tooling after firing; the powder itself is only mildly abrasive (Mohs 4.5), so it is gentle on compounding screws and paint mills compared with silica or alumina fillers.
Can Wollastonite be welded?
Not weldable; ceramic parts are joined by glass-frit sealing, glaze bonding or inorganic/epoxy adhesives.
Can Wollastonite be formed, bent or molded?
Dry-pressed, extruded or slip-cast in ceramic bodies where its low LOI and acicular habit give fast firing and very low shrinkage; as a filler it is melt-compounded at 15–40 wt % into thermoplastics or dispersed in coatings and friction resins.
What surface finishes work on Wollastonite?
Fired bodies accept conventional glazes and can be lapped/polished to a semi-gloss; in polymers the acicular grade slightly reduces surface gloss unless silane-treated fine grades are used.
Wollastonite chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| SiO2theoretical CaSiO3 = 51.7 % SiO2 | 48 – 52.5 | 51.7 |
| Fe2O3lower in high-brightness ceramic grades | 0.05 – 0.9 | 0.35 |
| Al2O3 | 0.1 – 1.2 | 0.45 |
| MgOfrom diopside/calcite accessories | 0.1 – 1.5 | 0.5 |
| MnO | 0 – 0.2 | 0.05 |
| TiO2 | 0 – 0.1 | 0.03 |
| K2O+Na2O | 0 – 0.5 | 0.15 |
| LOI<0.5 % for calcined grades | 0.2 – 3 | 1 |
| CaOtheoretical 48.3 % | ≥ 43 (balance) | — |
Wollastonite CAL — frequently asked
What is Wollastonite CAL used for?
Wollastonite CAL is typically used for low-shrinkage tile bodies, ceramic glaze fluxing agent, friction material filler and reinforcing filler in composites. In short: very low firing shrinkage; acicular reinforcing filler; low-abrasion mineral filler.
What is the tensile strength of Wollastonite CAL?
Wollastonite CAL has a typical tensile strength of 350 MPa (50.8 ksi) — stronger than 71% of ceramic grades. Strength varies by condition: see the 4 listed tempers.
Is Wollastonite CAL easy to machine?
Not especially — machinability is rated fair (42/100, better than 86% of ceramic grades). Fired wollastonite bodies are green-machinable before firing and require diamond tooling after firing; the powder itself is only mildly abrasive (Mohs 4.5), so it is gentle on compounding screws and paint mills compared with silica or alumina fillers.
Can Wollastonite CAL be welded?
Not weldable; ceramic parts are joined by glass-frit sealing, glaze bonding or inorganic/epoxy adhesives.
What surface finishes work on Wollastonite CAL?
Fired bodies accept conventional glazes and can be lapped/polished to a semi-gloss; in polymers the acicular grade slightly reduces surface gloss unless silane-treated fine grades are used.
Can Wollastonite CAL be formed, bent or molded?
Dry-pressed, extruded or slip-cast in ceramic bodies where its low LOI and acicular habit give fast firing and very low shrinkage; as a filler it is melt-compounded at 15–40 wt % into thermoplastics or dispersed in coatings and friction resins.
What is the maximum service temperature of Wollastonite CAL?
Wollastonite CAL is rated for continuous use to about 1,100°C (2,012 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Industrial Minerals & Rocks — Wollastonite chapter — SME (2006)
- Handbook of Fillers, 4th ed. — ChemTec Publishing (2016)
- Wollastonite functional filler grades (acicular / surface-treated) — Imerys / NYCO Minerals (2023)
- Mineral Commodity Summaries — Wollastonite — USGS (2024)
- GB/T (wollastonite powder for ceramics and fillers) product specifications (2020)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.