I'm currently working on a really simple project, an ashtray that can stop cigarette combustion.
I planned to put an aluminium block into my ashtray, with some kind of curves or holes in it, in order for the cigarette to fit in, then stop combusting by lack of $\ce{O2}$, and maybe by heat transfer, as the cigarette tip and the aluminium will be in contact.
I choose aluminium, because I've got some, because it seems quite inert to me, and because it's not too hard to work with. But I can't solve the safety estimation for this material.
Here is some information I found around :
- A cigarette tip being around $\pu{900^oC}$
- Aluminium point of boiling at $\pu{2519^oC}$
- Aluminium toxicity seems still debated, but aluminium is more or less eatable, i.e. used as pigment in food (E173)
Of course, aluminium won't burn, but I'm afraid that heating it may produce a layer of aluminium oxide, which may scatter on the cigarette tip, or get combined with ash components.
So, how can we estimate the safety of this material under these condition?