# 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.

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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. – Kamil Jul 12 '13 at 12:20
• It is possible you would get the sponge this way. It might still be worth a try. – Ben Norris 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 :) – Kamil 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. – user2617804 Jan 25 '14 at 4:22
• google.com/… – Dale Feb 17 '15 at 6:53

Well You need some kind of crystal structure even for sponge. Tin and copper forms an alloy and they have formed crystal structure together. So solving bronze in acid will destroy that structure, witch hold the peace as whole. Sponge can be formed from sintered peace if it is formed from zinc and copper powder. Then solving zinc whit acid will not destroy coppers crystal structure.