Wollastonite is a typical metamorphic mineral, which mainly occurs in the contact zone between acid rock and limestone, and also in deeply metamorphosed calcareous crystalline schist, volcanic eruption and some alkaline rocks. Its chemical formula is CaSiO3, structural formula is Ca3 [Si3O9], theoretical chemical composition: CaO 48.25%, SiO2 51.75%. Wollastonite belongs to a kind of chain shaped metasilicate, which is a triclinic system with fine tabular crystals and aggregates in radial or fibrous form.
Chemical parameters of wollastonite
| Component | XYSRW-A | XYSRW-B | XYSRW-C |
| Wollastonite Grade A | Wollastonite Grade B | Wollastonite Grade C | |
SiO2 (%) | 48-53 | 47-52 | 47-54 |
| CaO (%) | 43-45 | 38-42 | 35-40 |
| Al2O3 (%) | 0.15-0.30 | 0.15-0.30 | 0.15-0.30 |
| Fe2O3(%) | 0.2-0.3 | 0.3-0.5 | 0.5-0.6 |
| TiO2 (%)，Max | 0.02 | 0.02 | 0.02 |
| MgO (%) | 0.5-1.2 | 0.5-1.5 | 0.5-2.0 |
| S (%)，Max | 0.02 | 0.03 | 0.03 |
| P (%)，Max | 0.007 | 0.007 | 0.007 |
| L.O.I (1050℃) (%) | 1-3 | 4-8 | 6-18 |
| PH | 9 | 9 | 9 |
Physical parameters of wollastonite
| Item | Value |
| Particle Size (mesh) | 80- 6000 |
| Aspect Ratio（L:D） | 3:1-25:1 |
| Sedimentation Value (ml/200mg) | 40-150 |
| Oil Absorption (g/100g） | 20-55 |
| Whiteness（%） | 75- 92 |
| Refractive Index（%） | 1.63 |
| Density (g/cm2) | 2.95 |
| Coefficient of Expansion (mm/mm℃) | 6.5×106 |
| Melting Point (℃) | 1450 |
| Hardness (Mohs) | 4.5-5.0 |