Is it safe to heat fluorite (CaF2) to 140 °C?

For the manufacture of the optical system, we need to heat the fluorite ($$\ce{CaF2}$$) lenses to $$\pu{140 °C}$$. Is it possible:

1. for some poisonous gas to be emitted? ($$\ce{F2, HF}$$ or other)
2. for defects to appear on the glass? (scratches, chips, cracks and the like)

If yes, please supply sources describing the corresponding scenarios.

• The melting point is over 1400C. There's no way it can evolve F2 without electrolysis. Think you'll be safe at 140C – Waylander Dec 3 '18 at 12:38
• @Waylander Thanks, but I have concerns like operator live saliva (1 mg) which ph <7. Then there will be reaction which released HF. – Andrew Kachalin Dec 3 '18 at 12:44
• Unless your operators drool is highly acidic (pH1 or lower) then they are not going to produce HF. – Waylander Dec 3 '18 at 13:22
• @Waylander thanks, if you want give me answer below, and I'm ready to accept it. – Andrew Kachalin Dec 3 '18 at 14:06

The melting point of $$\ce{CaF2}$$ is over $$\pu{1400°C}$$. There is no way $$\ce{F2}$$ can be generated without electrolysis of the molten $$\ce{CaF2}$$. $$\ce{HF}$$ is produced by reaction of conc sulfuric acid on $$\ce{CaF2}$$. Concentrated $$\ce{HCl}$$ does react with fluorite to some extend, but the reaction is very slow so, unless your operators drool like the monster from Alien, there is no chance of $$\ce{HF}$$ formation.
• I guess you could link an MSFS showing how safe $\ce{CaF2}$ is … – Jan Dec 5 '18 at 15:24