Sciencemadness Discussion Board

Greek fire -- why not alum?

clearly_not_atara - 16-5-2021 at 08:48

The composition of Greek fire has long been a mystery, due to its disappearance and the general lack of chemicals available to the Byzantines who invented it. Many commentaries and experiments focus on quicklime as a water-reactive ignition agent, one of the few chemicals known to antiquity.

Another such substance with IMHO a better chance of being correct is aluminium sulfate and its related double salts, all well-known to the ancient Romans due to their use in water purification. The calcination of aluminium sulfate hydrates will give the anhydrous compound; heating these with tars may give some highly reactive organoaluminium compounds via reduction of the sulfate anions and subsequent ligand displacement or vulcanization (to aluminum thiolates). This is a rather simple process that could easily have been carried out thousands of years ago, though a lot of toxic byproducts will surely be produced as well.

However, aluminum compounds seem to be totally ignored in the analysis of Greek fire. This paper mentions alum, according to Google preview, at least:

https://www.proquest.com/openview/10208e7c0a2714a87b803b2f1f...

karlosĀ³ - 16-5-2021 at 09:18

I was never satisfied with the presentation of it being mainly explained by quicklime.
Thats stupid and far from what it was said to be able to do.
But your explaination... yeah, that could be right, I actually like that much more.
It would be sort of like what modern american flamethrowers are using.

MineMan - 16-5-2021 at 13:37

Wow. This is an amazing explanation

njl - 17-5-2021 at 04:43

Which "organo-aluminum" species are you suggesting? And by thiolate do you mean the sulfur analogues of alkoxide? Are they pyrophoric?

Nitrosio - 18-5-2021 at 05:42

http://pyrobin.com/files/Pyrophore5.pdf