Copper Sulphate To Copper

hi all!

if i were to add something of higher reactivity - e.g. carbon, to copper sulphate, would it be possible that i would get pure copper and carbon sulphate?

many thanks


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to get metal copper you need a reducing agent

probably any metal that has a lower redox potential would work, for example zinc
then you get zinc-sulfate and copper metal

what we did in our lab is: reducing copper-tetrammine complex with Dithionite. And you get copper and Sulfite. (The Subscripts don't work with my browser so I can't write down the equation.)

As FeLixe says you need a more reactive metal to displace the Cu[sup]+2[/sup] from the solution. Fe or Zn will work, giving greenish and clear liquids when the Cu[sup]+2[/sup] is out of solution. Mg[sup]+2[/sup] would also work, but the reaction would be so rapid that the Cu would be finely divided.

Carbon works, but usually we do it with copper sulphide, not sulphate.

No; these are entirely different reactions. 2 CuS + C > 2 Cu + CS[sub]2[/sub] is an oxidation reduction reaction, comparable to 2 CuO + C > 2 Cu + CO[sub]2[/sub];

The reaction mentioned here is an ion exchange in solution; there is no C(SO[sub]4[/sub])[sub]2[/sub] formed; if you stick graphite in blue rock solution you get a blue rock solution with graphite at the bottom. If you stick Zn or Fe in the solution, you get (after a while) Cu and white or green vitriol.

You can take CuSO[sub]4[/sub]and heat it to give CuO and SO[sub]3[/sub] and then reduce the CuO with C (or H[sub]2[/sub], but that's not the reaction that was asked about.

Anyway it has to get through CuO.

No, if solid Fe or Zn displaced Cu ions in solution, there is no CuO involved; presumably something like this generated the native deposits of Cu that are found.

I'm not sure where we are going here. The original question asked whether elemental carbon could reduce copper(II) ions to copper metal. The answer is that it doesn't in solution, almost certainly because carbon sulphate isn't a viable compound. Carbon, in the form of graphite, is able to conduct electrons, but cannot form positive ions, which is what would be required. To do so would demand a huge ionisation energy which simply would not be paid back by any other process. So solution reduction is out of the question. However I am pretty sure that the thermodynamics permit a high temperature reduction of CuO.

It is not done in practice because most of the copper extracted is required in a very pure state - >99% for electricity conduction - and electrolysis is the cheapest way to get there.

Reduction of CuO really doesn't require that high a temperature; of course high is based on your frame of reference, but a fairly common lab experiment in my day was a tube of CuO (in the form of black granules) in a tube and H[sub]2[/sub]gas passed through with an alcohol lamp beneath; as the heated H[sub]2[/sub]took up the O, the black granules became metallic Cu. A nice color change.

I get the impression that modern chem labs are big on measurement and low on spectacle; I suppose that none of you have ever poured AgNO[sub]3[/sub] into your lab partner's gloves.


Try electrodeposition! You just need a cathode / anode and a battery. I've done it with copper nitrate solution, deposited onto a nickel.

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