metalresearcher - 25-10-2010 at 11:47
According to this video
http://www.youtube.com/watch#!v=yh7SKa18EH0
NaOH reacts with aluminum. So I tried out some Al snippets (cut from a sheet of Al) mixed with some NaOH pellets (each ca. 1 gram) and put this into a
steel tube (2.5cm diameter x 5cm length) with one open end.
I heated the tube to dull red hot (ca 600oC) and saw yellow flames appearing in the tube. It was a mild reaction. Does hydrogen evolve or Na metal ?
With Mg then sodium metal appears ( tried that as well with Mg filings).
Sodium Aluminate
MadHatter - 25-10-2010 at 15:00
2 Al + 2 NaOH + 2 H2O ----> 2 NaAlO2 + 3 H2
The reaction releases hydrogen rapidly. This is how I used to create hydrogen to fill balloons.
bquirky - 25-10-2010 at 16:29
Its worth noting that the presence of even a small amount of zinc will dramaticly slow down the reaction between Al and NaOH The zinc will plate
itself out of the solution onto the aluminium reducing the available Al surface area.
Im not 100% sure how this works in a high temperature melt though.
This is a method that has been proposed to slow down the self discharge rate of Al primary battery's