Sciencemadness Discussion Board

Removal of Tin from Tinned Copper

toothpick93 - 1-9-2015 at 06:09

I received quite a lot of COMMS cable (I think) from my work that's getting a make over pretty much so they were just throwing it out, Yay free copper. At closer exception after I had removed the plastic coating I noticed a silver colour instead of your expected Copper colour, I cut some off and done the flame test and sure enough it was a green flame. I done some looking up on it and found it to be Tinned Copper Cable, How do I remove the Tin from the copper? I plan to melt the copper in a furnace but do not want the Tin impurity to be in the copper ingot.

I looked up some ways but none were in-depth, on the forum finishing.com people kept on saying about this method "You might try this: 120 g/l NaOH, make the part anodic at 6 VDC. You can vary the temperature to control the rate, but be aware that if you go too hot the copper might be attacked." but there is no procedure for this that I can find anywhere else. Does anyone else have any experience with this?

gdflp - 1-9-2015 at 06:13

If the tin is simply a coating on the wire, and is not alloyed with the copper, then use dilute(~3 - 6M) hydrochloric acid. Tin is readily soluble in hydrochloric acid, but copper is not.

Bert - 1-9-2015 at 06:37

Save the Stannous chloride if you use HCl, Tin is worth several times the price of Copper these days-

Why did they tin the Copper? And why is the new cable NOT tinned...

[Edited on 1-9-2015 by Bert]

aga - 1-9-2015 at 08:32

'Tinned Copper' generally means that it's been run through a solder bath, rather than just Tin.

Depending on it's age, that could have been a 60%/40% Tin/Lead solder composition, so your 'Tin' may contain quite a lot of lead as well.