# How to remove Sn from Sn60Cu40 alloy?

I have practical question.

How can I chemically remove $\ce{Sn}$ from $\ce{Sn60Cu40}$ alloy?

I want to get something like copper sponge this way.

Something like nanoporous gold produced from $\ce{Au50Ag50}$ for heat exchanger, but cheaper.

• Welcome to Chemistry.SE! I have edited your question to make it look better for our site. First, I removed the quotation marks from your title - they are unnecessary. Second, I used our MathJax plugin to make your chemical formula look like a chemical formula. You can learn to do this for yourself. Start by checking out the faq. Jul 10 '13 at 17:37
• @Kamil see chemistry.stackexchange.com/help/notation specifically Jul 12 '13 at 12:49

You can remove tin from bronze (copper-tin alloys) and leave behind the copper. However, doing so may not leave you with copper in an easy to use form.

Tin is a less reactive metal than copper. Tin reacts with all acids, like $\ce{HCl}$, while copper only reacts with oxidizing acids, like $\ce{HNO3}$.

$$\ce{Sn(s) +2H+(aq) -> Sn^{2+}(aq) + H2 (g)^ }$$ $$\ce{Cu(s) + 2H+ (aq) -> No \ Reaction}$$ $$\ce{Cu(s) + 4H+(aq) + 2NO3- (aq) -> Cu^{2+} (aq) + 2H2O (l) + 2NO2 (g) ^}$$

Soaking your bronze in acid (even vinegar might work) will eventually dissolve the tin away from the copper. Heating, or using a stronger acid like the $\ce{HCl}$ in muriatic acid, will likely increase the rate. However, since the composition of the alloy is uniform throughout, the copper will likely come out of solution as a fine powder.

• Well... Powder will not satisfy me. Please take a look at my updated question. Jul 12 '13 at 12:20
• It is possible you would get the sponge this way. It might still be worth a try. Jul 12 '13 at 15:38
• I think, that Sn/Cu ratio is not 50/50 and it may not work, but I have to try :) Jul 12 '13 at 19:53
• Selective corrosion would definitely produce a copper sponge but I don't what chemicals selective removes tin in a tin/copper alloy. Jan 25 '14 at 4:22