ask aluminium Forum

Firstly, I want to know if the product from this is Al2O3 (Aluminium Oxide):

I took a piece of Aluminium foil and lightly crumbled it into a ball. I weighed the Al foil ball, it was 0.334g. I then torched the Al ball with propane until near destruction, the aluminium foil shrunk and changed colour to a more dull grey metallic surface. Once cooled, I weighed the now smaller and harder Al ball and the weight was 0.38g, an increase of 0.044g which I beleive is due to oxidation. Is the product aluminium oxide? Or a partial oxidation?

Secondly, what is a good 1step method to create aluminium oxide from aluminium foil with a high grade yield? I already know of the aluminium and NaOH to create aluminium hydroxide is then heat until it decomposes to aluminium oxide; < which I think is one step too many.

I appreciate any input. And thanks for reading.

Al2O4 is the only stable oxide around STP, so "partial oxidation" would mean having unreacted Al metal. Calculated what weight of Al2O3 you should get with 100% reaction and compare.

And that's the problem - the oxide layer does a good job at protecting the underlying metal that it's difficult to get full conversion. You'd do better finding some Al2(SO4)3 in a garden supply store and precipitating the hydroxide using NaOH, Na2CO2, NaHCO3, or even aqueous ammonia. The product will be purer as well, most metallic Al is some alloy or other.