Fluorine Gas
Various material used in ceramics can generate fluorine gas during firing. This gas in hazardous, for example ILO says: Avoid all contact and in all cases contact a doctor.
For example, fluorspar contains alot of fluorine has a TLV (threshold limit value) of 2.5 milligrams per cubic meter of air breathed. By comparison iron oxide is considered a safe-to-use material at 5.0, kaolin is 2.0, barium carbonate is 0.5, quartz is 0.1-0.05.
Cryolite also contains a very large amount of fluorine and thus poses a specific hazard. Even Cornwall Stone, a widely used glaze material, can contain up to 2%.
Good kiln ventilation is essential. Over a period of time, fluorine gas will even etch windows in the kiln area until they are opaque like frosted glass. This is ample evidence of its presence.
Related Information
Links
| Materials |
Fluorspar
|
| Materials |
Cryolite
|
| Materials |
Cornwall Stone
|
| Materials |
Petalite
|
| URLs |
http://www.ilo.org/public/english/protection/safework/cis/products/icsc/dtasht/_icsc00/icsc0046.htm
Fluorine Hazards at ilo.org |
| URLs |
http://en.wikipedia.org/wiki/Fluorine
Fluorine at Wikipedia |