aluminium + sodium hydroxide + water = aluminium hydroxide???? help please

[ResinRat2]

http://www2.uni-siegen.de/~pci/versuche/english/v44-10.html

You will get a gooey mess.

So what was the question?

[ResinRat2]

DAVE
A lot of towns in the USA have started land filling recyclables [no longer cost effective]
Chet

That is interesting. Where I live they still collect them.

Actually, this reaction can be controlled somewhat. Don't worry about the ratios of the reactants. What you want is to CONTROL the reaction rate and one way to do this is to add one component into the other in a controlled manner.

You can have one container that holds the aluminum and slowly drip the NaOH solution into it. This would control the heat and gas rate off: or you could hold the NaOH solution in one container and slowly add the aluminum powder into it. Stopping the addition would allow the reaction to peter out and stop at that point,.

Just an observation on ways to possibly control the reaction rate. You won't be able to INSTANTLY stop the reaction, but you can allow it to slow and stop in a controlled manner.

[hansvonlieven]

G'day Dave

Isn't this similar to making acetylene gas with calcium carbide. They used to dribble water on the calcium carbide in measured quantities to generate the required amount of gas. You also wind up with a gooey mess in the container after a while.

Hans von Lieven

[ResinRat2]

Hi Hans, I used to go Spelunking in my younger days and there were people that swore by the carbide lamp over the battery lamp. You are right though, you would end up with a mess at the end that had to be disposed of.

The same with this idea.

I actually did a long series of experiments trying to get this reaction with the aluminum and sodium hydroxide under control. I was using the theory that the aluminum could be regenerated at the same time the hydrogen was being produced. I always came close to controlling the regeneration, but no matter how carefully I regulated the regeneration voltage, the aluminum was always either consumed or plated on to the tungsten cathode.

The bad part about this aluminum-hydroxide experiment is that in the end you are left with toxic waste that can't safely be just thrown down the sink. It would need to go to a toxic landfill.

[sparks]

    Aluminum is expensive because of the amount of energy needed to extract it from it's mineral bonding.  Any gain is basically getting the energy back that was used to get it into it's elemental form.  You can burn limestone but that isn't very friendly.