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Electricity from aluminium


chilled_fluorine

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Aluminum is not a good choice for making electricity, aka batteries. Its oxide forms an impervious coating which makes it hard to keep chemical activity going. Also the first electron yeilds 5.3 volts, the second about 3.4 and the third about 1.7, but the battery only produces the lowest voltage, so much of the energy is wasted.

 

When 'they don't do this', it's usually because they found out it's not such a good idea. And that is why you won't find Aluminum batteries at the store.

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Aluminum is not a good choice for making electricity, aka batteries. Its oxide forms an impervious coating which makes it hard to keep chemical activity going. Also the first electron yeilds 5.3 volts, the second about 3.4 and the third about 1.7, but the battery only produces the lowest voltage, so much of the energy is wasted.

 

When 'they don't do this', it's usually because they found out it's not such a good idea. And that is why you won't find Aluminum batteries at the store.

 

Aluminium batteries are quite practical on a large enough scale. Many chemicals can dissolve the oxide layer, and it's not even necessary. I really don't care about even 80% wasted energy, so long as I get some electricity and aluminium hydroxide that I can dehydrate to the oxide.

 

How much electricity goes to produce I kg of aluminium ? A friend and I were discussing aluminium recycling as a method of energy

 

That was a little vague... don't you think? I didn't pay for it, so I couldn't care less about how much electricity someone in China used to make it. Anyone know how I could trade my al for mg?

 

Solar flat plate collectors ?

 

What?

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Take your aluminium and make a heat collector which basically will sit in the sun and heat up. Use the fact that you will then have a big lump of hot metal as a source of heat to make electricity.

 

But I could use almost anything for that... And it won't consume the aluminium. I want to tap its chemical energy. I don't have or feel like making a heat collecer of any useful size. I do have a giant fresnel lens though, that could work.

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In principle the best way to do this is to take the Al to an aluminium factory where they electrolyse alumina to produce the metal and ask if you can swap the scrap metal for the equivalent amount of oxide.

The electricity saved by not making that ore into metal is the best yield of electricity you will get for the aluminium. (of course, in practice, they won't care about your tiny little bit of scrap- they will probably tell you to take it to a scrap dealer)

Let's just see how much electricity you could hope to get.

 

If you have a ton of Al that's 37 Kmol

It will give 111 Kmol of electrons

67 E27 electrons

11M Coluombs

 

It will give a couple of volts or so which makes the energy available about

21 MJ

About 6000 KwHr

Roughly on a par with the electricity needed to produce it according to this

http://agmetalminer.com/2009/02/26/power-costs-the-production-primary-aluminum/

That page also answers Jimmy's question "How much electricity goes to produce I kg of aluminium ? A friend and I were discussing aluminium recycling as a method of energy " It's about 15000 KwHr/ton

 

 

Local electricity prices are a bit variable but a ballpark figure would be 0.1$/KwHr

So the electricity you could hope to get from your ton of metal is worth about $600

(assuming that you are happy to use it to power something like LED lighting that can consume the power directly at the rather low voltage it is produced at from a simple battery.)

 

Is it worth the trouble?

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1 kg of Aluminium will be 21 MJ or about 6 kWh, or about 60 cents

 

1 ton of Aluminium will be 21 GJ or about 6 MWh, or about 600 euro or dollar.

 

That's obviously at 100% efficiency. It's the theoretical maximum. In practice, it will be less. Also, you have probably not even figured out how to control the reaction speed, so you don't blow every fuse in the neighborhood when you explode all that electricity onto the grid.

 

If you have pure aluminium, just sell it to a scrapyard. They will recycle it, which is best for the environment, as well as for your bank account.

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For the benefit of everybody having a read here , how much electricity are you trying to make ? 1 microwatt second or 100 megawatt hours ?

 

"I wish I had enough money to buy a hippopotamus." "Why?" "I don't know why, I just want the money."

 

I just want to do a few experiments off grid... Gosh. I have other means of doing this, I just figured I'd make some al2o3 in the process, and de-clutter the workshop/lab. Al2o3 can be ridiculously hard to find... So perhaps I shall ask: HOW CAN I MAKE AL2O3 WITHOUT AL POWDER?

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