# How to deplate copper?

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I have a quick question. I would like to remove the copper coating from a modern U.S. Penny in order to obtain the zinc inside, but with the form of a penny. Is there any easy, relatively safe, way to remove the copper without damaging the zinc? I was thinking of electro-plating the copper off of it, but I figured that the zinc would react with the copper and displace it from solution. Is there a simple chemical way? Could I just soak the penny in bleach, and every day or so take it out and remove the copper chloride/hypochlorite that builds up on the surface until all the copper is gone? I'm just having some cerebral flatulence with this one.

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youre quite right, the copper will come off 1st, and then the 1st tiny bit of Zinc exposed and its ball game over, Displacement city!

you could dissolve the whole thing though! and recover your copper AND zinc later though

although I dont know why you just dont strip down some old dead Alkali batteries and get your Zinc that way? or even the casing from old zinc carbon types?

Edit: just as an afterthought, Ive done a similar set of experiments along these lines before, I use NH4NO3 soln and it dissolved the copper just perfectly! (dont ever let the soln crystalise after though!). itll make Tetramine copper 2 Nitrate.

I tried the same with Zinc metal, and the reactuions still going as of 8 months ago, it hardly wants to touch the Zinc at all. although I DONT have any experimental data as to displacemnet in this though, I did the 2 seperately, but eitherway, itll only cost you a penny to find out

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I found it very easy just to melt the zinc and because the copper is so thin it easily rips and the pure zinc pours out. Or to make it easier you can file down one side then melt and pour.

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Well, the reason why I want the zinc un-harmed is that I'd like to have the impression of the penny, but without the copper. I think it'd be pretty neat to show that a penny is made out of pure zinc, and removing just the copper part would show the original penny, but made out of zinc. I'll have to get some NH4NO3 and try the copper removing that way. One question though; since I'd have no use for the solution afterwards, how would I go about making it not 'KA-BOOMABLE'?

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My idea just isnt good enough for you eh? I see how it is....

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hehe. The idea is fine, but me + high levels of heat generally = UH-OH. lol. I do have a few zinc samples from where I used a grinder and ground away the copper outer plating. But having a sample that looks just like a penny, but made of zinc, would be pretty cool to have.

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How about a penny without the zinc? You could drill a tiny hole in the side then drop it in some hydrochloric acid. It would be cool to have a solid zinc penny though.

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I've done that before. We did it in High School Chemistry lab. It was pretty neat. We also took a copper penny and soaked it in a strong NaOH/powdered Zinc solution, then heated the penny in a bunsen burner flame. The copper and zinc alloyed and made the surface a nice golden brass color.

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I Zinc plated a penny the other day. I dissolved some zinc in some HCl, then connected the penny to the negative terminal of a transformer (18V, 2.23Amp, not sure if it matters) and another chunk of zinc to the positive terminal, and placed both of them into the Zinc Chloride solution. It worked rather well, put a thin layer of zinc onto the penny.

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I was going through my back closet and saw that I had an old amber glass bottle that I had kept Iodine in for a while. To clean the bottle, I had filled it with isopropanol a few years ago and forgot about it. Now I have a superconcentrated iodine solution. I decided to just soak a penny in that for a while until enough corrosion has occured to remove the outer copper covering. Some zinc will wind up being destroyed, but not too much as long as I watch it every day and occasionally clean the penny. (Though all this dissolved iodine will make a mess. heh.)

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I'll have to get some NH4NO3 and try the copper removing that way. One question though; since I'd have no use for the solution afterwards, how would I go about making it not 'KA-BOOMABLE'?

just keep it in soln, dont allow any large crystals to form, and then pour it down the toilet when its finished.

you wouldnt make enough for a KaBooom, but larger crystals can detonate loud enough for you to drop your equipment, although youde be very unlucky for it to happen, its not impossible and worthy of a mention

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just keep it in soln' date=' dont allow any large crystals to form, and then pour it down the toilet when its finished.

you wouldnt make enough for a KaBooom, but larger crystals can detonate loud enough for you to drop your equipment, although youde be very unlucky for it to happen, its not impossible and worthy of a mention [/quote']

Heh. Gee thanks for giving me some evil ideas.

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if you recon youre smart enough to work with such compounds that even the Military turned down as a viable primary, anfd yo recon you can do it with toatly impunity, then be my guest!

MY ADVICE AND ALSO IN COMPLIANCE WITH SFN REGULATIONS IS NOT TO DO THIS!

there, Ive said my peice, the rest (in fragments or not) is up to you

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I'm happy to say that my iodine-in-isopropanol method seems to be working. I've had a penny soaking in the solution overnight, and the deep, dark red-brown color of the solution has faded quite a bit, and there's a very fine powder of, I'm guessing, CuI or CuI2 on the bottom of the vial. Plus, on the high points of the penny, where the copper plating is probably the thinest, it looks as if a silvery colored metal is starting to show. Now while this probably won't turn out as a completely shiny and clean with full detail zinc penny, I think a good majority of the detail will remain.

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I Zinc plated a penny the other day. I dissolved some zinc in some HCl, then connected the penny to the negative terminal of a transformer (18V, 2.23Amp, not sure if it matters) and another chunk of zinc to the positive terminal, and placed both of them into the Zinc Chloride solution. It worked rather well, put a thin layer of zinc onto the penny.

Keep the voltage around 3V and have th amps as you wish, higher the better. you will get a great results that way.

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Keep the voltage around 3V and have th amps as you wish, higher the better. you will get a great results that way.

Thanks for the tip! I was just using what I had around, I'll see if I can find a 3V transformer.

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• 3 months later...
you could dissolve the whole thing though! and recover your copper AND zinc later though

How would you go about doing that? Can you get the zinc out, and then get the copper out? Or do they come out at the same time. I just would like to make zinc powder. Thanks.

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youde have to fractionaly crystalise the mix os solns and separate the copper sulphate crystals from the zinc sulphate, then redissolve them and electroplate the zinc or copper back out.

but if you just want Zinc, why dont you just strip down some old Zinc/Carbon batteries?

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Because I want to do it the hard way Im assuming that you used sulphuric acid? If so, what concentration?

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This might be a bit easier to do. Take a bunch of pennies which are dated AFTER 1982 and scrape off a small notch on the side to expose the zinc core. You then take these notched pennies and put them into any acidic solution. A weak sulfuric acid solution or a weak hydrochloric acid solution will do a fine job of dissolving the zinc and not even touching the copper. You'll then have your zinc ions in solution which you can crystalize out without any worry about copper contamination.

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Cool, thanks jdurg.

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• 2 weeks later...

I put some pennies in a ammonium nitrate soln, forgot about it (literally) for about a week and a half, to find that the soln turned blue. Some bits of copper remained, but the zinc and the rest of the copper was gone. There was also a white percipitate at the bottom. Can anyone tell me what the percipitate is, and what compound of copper it is? Thanks!

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probably zinc hydroxide

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Cool, thanks. Is the soln a soln of copper hydroxide then? Or of tetramine copper 2 nitrate that was mentioned above?

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i think you got the tetraamine cupric nitrate complex

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