Silicates (particulate) — properties & hazards overview
Physical state
Solid particulate (dust)
Typical size range
0.5 – 50 µm; respirable fraction < 10 µm
Density
2.2 – 2.7 g/cm³
Water solubility
Practically insoluble
Toxicity
Low acute toxicity
Flammability
Non-combustible
Chronic risk
Silicosis; IARC 1 (crystalline)
Environmental
Deposition; abrasion
| Property | Value / Note |
|---|---|
| Scope | Crystalline silica (quartz, cristobalite), amorphous silica, and the silicate minerals — talc, kaolin, mica, calcium and sodium silicates. |
| The distinction that matters | Crystalline silica is the carcinogen; amorphous silica is not classified as such. Analyse before you assume — the control philosophy differs. |
| Physical behaviour | Insoluble and dense; captured mechanically, not chemically. Abrasive at every velocity change in the system. |
| Occupational limits | Respirable crystalline silica typically 0.05–0.1 mg/m³ TWA — verify against local regulation. |
| Typical sources | Pulp, paper and coatings, cement and minerals processing, foundry sand, glass and ceramics, precipitated silica production. |
| Best analytical detection | Isokinetic gravimetric PM sampling (EN 13284-1 / EPA Method 5) for total mass, followed by XRD or FTIR on the respirable fraction to determine the crystalline silica content. |
*Indicative values; verify via SDS and process data. Classification hinges on the crystalline fraction — have the dust analysed rather than assumed.