

Open Source Aluminum - ph0rque
http://openfarmtech.org/weblog/2010/12/open-source-aluminum/

======
sbierwagen
Wow that's a noisy video.

Anyway, this is just about extracting aluminum oxide from clay, instead of
bauxite. You still have to smelt it, and they're proposing using the Hall-
Heroult process, which is dissolving aluminum oxide into cryolite, and
electrolyzing it.

This is _heavy industry!_ Cryolite melts at 1000C, and isn't a terribly common
mineral, and the electrolysis consumes a _lot_ of power, and is about as
environmentally friendly as a not at all friendly thing. This is in large
plants, with modern emissions controls, and they're saying that a small open
cycle plant is going to be green, with a straight face?

Meanwhile, you can smelt iron in an open pit fire, without acids, molten
cryolite, or electricity.

~~~
pingswept
Also, the chemical they're planning to use to do the extraction, hydrofluoric
acid, is extremely dangerous. You can't feel the burns at first, and the
fluoride reacts with the calcium compounds in your bones-- not pleasant stuff.

<http://firegeezer.com/2009/08/11/whats-the-hf/>

------
jefflinwood
Interesting, but for the context of the project (self-sufficient villages)
what's the energy requirements?

Aluminum isn't scarce (most abundant metal in the earth's crust), but turning
alumina into aluminum requires a lot of energy. Check out the Hall process if
you're interested, or for way more information, get a BS in chemical
engineering like I did :)

The rest of their web site is kind of fascinating, if you want to completely
repudiate Adam Smith.

~~~
pontifier
The energy requirements bother me too..

I keep dreaming of slower and more efficient aluminum recycling/extraction. My
fantasies mostly revolve around solar concentration in a vacuum chamber. e.g.
heat the material containing aluminum and impurities to it's melting point
while extracting all gases evolved.

I'm not sure how Aluminum Oxide would react in that environment, but I think
it would be fun to find out.

~~~
pontifier
So, upon closer reading the article is about Aluminum Silicate, not Aluminum
Oxide. And the process I'm describing is thermal decomposition...

after looking here: <http://www.sciencemag.org/content/139/3559/1055.short>
and here: <http://cnx.org/content/m24918/latest/>

I find that Aluminum Silicate would most likely turn into a gas itself before
I could extract the oxygen in my solar chamber... hence the need for the
hydrofluoric acid to bind to the Aluminum...

Sometimes I wonder why I dream at all.

------
lucasjung
"We may be able to build such a facility for about $50k, under drastic cost
reduction assumptions of open source economic development."

Translation: "We're assuming that the economic system we dreamed up, which
hasn't actually been applied on a large scale anywhere in the world, will make
the previously unaffordable suddenly cheap."

