Sciencemadness Discussion Board - Electrolytic aluminum powder?

Electrolytic aluminum powder?

ch3misc00l - 27-1-2016 at 17:11

I was thinking if the electrolysis of a weak acid salt of aluminum like aluminum acetate can yield aluminum powder, but i was thinking that the water can react further with the nano aluminium powder to make aluminum hydroxide. If this happens, can aluminum acetate disolved in some solvent like ethanol
yield aluminum powder?
I can make a good amount of aluminum acetate from calcium acetate and aluminum sulfate.
Pd : I have a ball mill and i use it to make aluminum powder , but if this method works it would be much better because the aluminum is not cast and will have a very small particle size , without the need of milling it.
And about the electrodes , i think that graphite cathode/anode will work.

Detonationology - 27-1-2016 at 17:22

To my knowledge, only group 1 metals form hydroxides in contact with water. Iron powder in water will produce iron oxide (rust). The same is likely to occur with Al, with the formation of Al2O3.

ch3misc00l - 27-1-2016 at 17:51

Quote: Originally posted by Detonationology

To my knowledge, only group 1 metals form hydroxides in contact with water. Iron powder in water will produce iron oxide (rust). The same is likely to occur with Al, with the formation of Al2O3.

And if i use ethanol/ some solvent in which aluminum acetate is soluble? I know that aluminum triethoxide exists , but it only forms when aluminum-mercury amalgam reacts with ethanol , or boiling ethanol with aluminum powder and aluminum chloride, but i think that the ethanol will serve as an inert solvent here.

[Edited on 28-1-2016 by ch3misc00l]

Detonationology - 27-1-2016 at 18:04

I am not sure I follow 100%, but if you are asking what I believe you are, electrolysis cannot be preformed in pure alcohols because they are non-electrolytes. If you are familiar with aluminum powder, you are probably also aware of "dark aluminum powder." The reason it is dark is because charcoal is added to cover the aluminum and protect it from oxidizing. Oxidation is the biggest issue when it comes to making fine metal powders. That's why charcoal is typically added during the ball milling process. It is likely that if very finely powdered aluminum wasn't covered in charcoal, that it could prove to be pyrophoric

ch3misc00l - 27-1-2016 at 18:20

Yes , i know that aluminum powder needs to be coated in charcoal to increase reactivity and lower its unstability. I have made fine aluminum powder without charcoal with no accidents using ceramic grinding media , but the stuff is scary , and it can be light with just a spark from a lighter, and it can burn spontaneously . I was so lucky that doesn't happened to me, and it was the first time i made aluminum powder. I heared of a lot of accidents and dust explosions involving pure non charcoal-coated aluminum powder.
In resume, better i search another method of making aluminum powder or upgrade my tiny ball mill

[Edited on 28-1-2016 by ch3misc00l]

Detonationology - 27-1-2016 at 18:25

Sorry, I didn't mean to insult your intelligence, I was just reiterating the reactivity of aluminum powder.

ch3misc00l - 27-1-2016 at 18:32

No , i was wrong about this , i am beginner at chemistry , don't worry. But i will continue researching , maybe i found something interesting.

blogfast25 - 27-1-2016 at 18:34

Quote: Originally posted by Detonationology

That's why charcoal is typically added during the ball milling process. It is likely that if very finely powdered aluminum wasn't covered in charcoal, that it could prove to be pyrophoric

No. Carbon-free Al powders are very common. Al passivates in air immediately and isn't pyrophoric in the slightest.

https://en.wikipedia.org/wiki/Passivation_(chemistry)#Aluminium

It's also extremely hard to make it burn, for the same reason.

Electro-deposition of electro-positive metals like Al from water is basically impossible. So Al powder can't be produced electrolytically, from aqueous solutions.

ch3misc00l - 27-1-2016 at 18:45

I am still thinking that some water-free solvent in which an aluminum salt is soluble , when electrolysed will produce aluminum powder. Also aluminum isopropoxide electrolysis could produce aluminum powder, but it would be impractical due to aluminum isopropoxide rare availability and expensiveness.

[Edited on 28-1-2016 by ch3misc00l]

blogfast25 - 27-1-2016 at 18:49

Quote: Originally posted by ch3misc00l

I am still thinking that some water-free solvent in which an aluminum salt is soluble , will produce aluminum powder. Also aluminum isopropoxide electrolysis could produce aluminum powder, but it would be impractical due to aluminum isopropoxide rare availability and expensiveness.

[Edited on 28-1-2016 by ch3misc00l]

Good luck. A $1000 tells me you won't succeed were so many have failed before. Al isopropoxide isn't even a real salt: MP about 140 C!

Detonationology - 27-1-2016 at 18:50

Solid pieces or sheets of aluminum are indeed capable of passivation; however, metal powders under 5 microns tend to become more reactive. There isn't much room for passivation when the particles are that small.

Here is some references too:
https://en.wikipedia.org/wiki/Pyrophoricity
http://cameochemicals.noaa.gov/chemical/14570
http://www.ehs.pitt.edu/assets/docs/combustible-metals.pdf
http://www.dtic.mil/dtic/tr/fulltext/u2/b270510.pdf
http://ehs.unl.edu/sop/s-pyrophoric_%26_substances.pdf

[Edited on 1-28-2016 by Detonationology]

ch3misc00l - 27-1-2016 at 19:12

Quote: Originally posted by blogfast25

Quote: Originally posted by ch3misc00l

Good luck. A $1000 tells me you won't succeed were so many have failed before. Al isopropoxide isn't even a real salt: MP about 140 C!

I forgot to say , it would only work with MOLTEN aluminum isopropoxide.Molten salts are the only routes to aluminum metal as i am searching. But i think that melting a flammable solid that reacts with water is not a good idea, and electrolyzing it would be worse. So , some organoaluminum room temperature melting point compound could be the "safe" way to get aluminum powder without ballmilling / powderizing the metal.

Detonationology - 27-1-2016 at 19:18

Quote: Originally posted by blogfast25

Al passivates in air immediately and isn't pyrophoric in the slightest.

https://en.wikipedia.org/wiki/Passivation_(chemistry)#Aluminium

Quote:

Pure aluminium naturally forms a thin surface layer of aluminium oxide on contact with oxygen in the atmosphere through a process called oxidation

However...

Powdered aluminum...

Quote:

Can be ignited under almost all ambient temperature conditions.

Quote:

Finely divided metals (iron,[3] aluminium,[3] magnesium,[3] calcium, zirconium, uranium, titanium, bismuth, hafnium, thorium, osmium, neodymium)

...are pyrophoric.

Quote:

In
finely divided powder or dust form, aluminum and its alloys are combustible in air and
present a serious combustion explosion hazard.

So...

Quote:

Please be more careful when citing, in the future. You pulled that seriously out of context.

[Edited on 1-28-2016 by Detonationology]

[Edited on 1-28-2016 by Detonationology]

deltaH - 27-1-2016 at 22:25

Aluminium metal can be deposited in a mirror form from chloroaluminates dissolved in an anhydrous choline chloride deep eutectic solvent. See pp.13,14 in this long presentation and it's reference for more info:

https://wet.kuleuven.be/english/summerschools/ionicliquids/l...

It does not, however, produce powder... nor do I think it could be made to do so easily, yet it is interesting as an example of room temperature electrolysis that forms aluminium metal.

I do not think that molten aluminium isopropoxide would be conductive due to lack of ionisation.

blogfast25 - 28-1-2016 at 04:12

I don’t think it’s accurate to describe Al powder as pyrophoric in the strict sense of the word:

Quote:

A substance that ignites spontaneously in air at temperatures below 55 C (Celsius)

Instead I think there’s conflation going on, leading to an inaccurate ‘reputation’:

• Pyrophoric Al compounds do exist: see alkyl aluminium
• Al powder reacts very strongly with strong oxidisers, 'burning' past the MP of alumina
• Used in fireworks

I’ve used various grades of Al powder, including some of the finest and purest, all my life. I’ve also mixed it with KClO₃, KNO₃, NaNO₃, S and even KClO₃ + S, without the slightest incident.

With something like MnO₂ you get close to a flash powder but not without heating it strongly (igniting with hot source). And smooth running MnO₂ thermite formulations I’ve also created (with CaF₂ or CaO).

Detonationology - 28-1-2016 at 04:41

Quote: Originally posted by blogfast25

Pyrophoric Al compounds do exist

Somebody should go to and tell those 3 sources I posted that they have been publishing false info.

blogfast25 - 28-1-2016 at 04:55

Quote: Originally posted by Detonationology

Somebody should go to and tell those 3 sources I posted that they have been publishing false info.

For one, I didn't say 'false', I said inaccurate. They're not the same thing.

And Al compounds do not equate to Al powder.

Much as I use and respect, e.g. Wikipedia, it's full of errors and poor cut'n paste jobs. Not everything you read on the Net is true. And not everything you read should be taken literally.

[Edited on 28-1-2016 by blogfast25]

ch3misc00l - 28-1-2016 at 07:43

http://www.materialstoday.com/metal-finishing/features/depos...
Interesting..