[NewCandle] Cobalt versus iron hydroxides

[Keith Nagel]

Hey Nick,

Thanks for the help! At this point, those hydroxides
are all oxides, thanks to evaporation and time.
The iron oxide seems mostly to be black magnetite,
and I _think_ the cobalt oxide is also magnetic.
I'll try magnetic separation tonight after they
completely dry to a powder.

As I mentioned earlier, there's no reason I can't
redissolve this into another mineral acid ( I've
got the big three ) and work with whatever salt
is convenient. 

Typically when I try to do this kind of thing,
I look for a chemical reaction that produces
an insoluble salt of just one of the components.
In this case, the chemistry of both elements is
(as you say ) so similar that nothing came to
mind.

For what it's worth, the reactions I described make
a nice ferrofuild substitute. I'm sure I could do
it with just plain iron, and I might try just to get
a better feel for the difference.

K.

-----Original Message-----
From: newcandle-bounces at ipdiscover.com
[mailto:newcandle-bounces at ipdiscover.com]On Behalf Of Nick Reiter
Sent: Thursday, February 22, 2007 12:12 PM
To: New energy for the new world.
Subject: [NewCandle] Cobalt versus iron hydroxides


Hi Keith,

OK, dang it, I have to toss in the towel on your
separation of Co and Fe hydroxides problem, with nary
but a vague suggestion.

The solubility and reactivity of the two - from
everthing I can glean from the CRC manual is damned
near identical.  The even weigh nearly the same, so
there goes any easy centrifuging.

I had a devil of a time finding specific magnetic
susceptibilities for those two compounds, however in
general it looks like Fe oxides and sulphides are a
little more paramagnetic than corresponding cobalt
compounds.  They are also a different color - FeOH2
being supposedly a pale green color, and CoOH2 being a
reddish color.  So maybe with a strong magnet, a lot
of shaking, and a keen eye for color, you might be
able to pull it off.

I thought that maybe one might have a higher
decomposition temperature than the other, but I
couldn't find any data for that.

Sorry I drew such a blank!  Anyone else come up with
any ideas?

NR


 
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