A different take on yet another Making Copperas thread

[jason_recliner]

It doesn't take much searching to find a 10% solution of sulphuric and some iron is the path to clean copperas, and that is a process I have started. But I've run out of battery acid and it's tough to find even the 30% stuff without buying another motorcycle battery.

I've have a an idea I have been researching a couple of weeks, but would like to run it by those who might know better. I know it's an expensive way to get things done.
Since iron will replace copper in a chloride, presumably it will in a sulphate or most other solutions.

I have some ordinary copper sulfate, the regular blue pentahydrate crystals: CuSO₄ 5H₂O. According to https://en.wikipedia.org/wiki/Metal_aquo_complex it goes into solution as Cu(H₂O)₆²⁺. I struggle a little with the valences thing but this page shows the target blue/green copperas as an identical formula except Cu -> Fe.

So it sounds like it could work. ??

Now https://en.wikipedia.org/wiki/Iron(II)_sulfate shows there are a whole heap of hydration states but heptahydrate is the blue/green colour described. Does anyone know whether the hydration state even matters for refining purposes?

An initial test of some transformer lamination in some blue solution quickly coats it with copper. (Though after a few hours it has so far stuck with a copper coating and is not yet shedding it.) As long as I somehow keep it from becoming too oxidised, am I on the right track?

(Edited grammar)

 

[g_axelsson]

The hydration state doesn't matter, it's only for the salt. In water it will be in solution and fully hydrated. :mrgreen:

What is important is the oxidation state. You might want to boil the solution first to get rid of as much dissolved oxygen as possible.
I don't know if it will make any difference though.

Göran

 

[jason_recliner]

Thanks Göran.
I did suspect that about the hydration state. But still such a chemistry "noob", I am never keen to make any assumptions on anything unproven.
Boiling to remove O2(g)...? That's new to me, but somehow makes perfect sense. Just for curiosity, would that start working from say 80°C or so?

 

[g_axelsson]

Look at boiling water just before it starts to boil, there's a lot of small bubbles forming and rising to the surface. Bubbles of steam rises too but is getting smaller closer to the surface.
Gasses dissolved in water is most soluble at low temperature and as least at high, to remove gasses heat the solution. It also works on chlorine.

The following experiment is done on pure water and not with poisonous copper sulfate solution.
Try to boil drinking water and let it cool down with the lid on, then taste it and compare it to water that hasn't boiled. When boiled water has lost it's oxygen the taste is a lot less sweet.
Then pour it between two glasses a couple of times so there is oxygen mixed in again, then taste it. 8)

Göran