Sciencemadness Discussion Board

Cadmium metal from NiCd batteries, and conversion to soluble salt. + Hazards

Rhodanide - 7-3-2018 at 06:39

In my quest to make all the Oxalates that I can, Cadmium is next!
Is it correct that NiCd batteries contain a perforated foil of pure Cd metal, or is it a salt? Also, how would I turn the metal into a salt, if it is in metallic form? What acid works best? One last thing - anything I should know about Cd besides its toxicity before I go to work with it?

ninhydric1 - 7-3-2018 at 08:50

Magpie made a (successful, sorry Magpie) attempt at extracting Cd from batteries in the following thread:

http://www.sciencemadness.org/talk/viewthread.php?tid=4676

[Edited on 3-7-2018 by ninhydric1]

Magpie - 7-3-2018 at 09:51

What do you mean “attempt”? I did it.

elementcollector1 - 7-3-2018 at 13:15

I've done it as well. The cadmium inside is a gray, slightly clumpy powder pasted onto a steel support mesh, and needs to be scraped off vigorously with a screwdriver. I'm not sure how pure it actually is, but dissolving it in an acid and plating it out again at very low voltage (to avoid iron plating, etc.) would probably give a reasonably pure metal product.

Personally, I used H2SO4 and got about the same color as Magpie's cadmium nitrate. I don't quite recall how it behaves in HCl, but I've no reason to suspect any of the three main acids are any better or worse than the others in this case.

j_sum1 - 7-3-2018 at 14:36

This is on my list -- I have an old nicad drill battery that no longer holds charge that I picked up from somewhere. I have not yet looked up how these are constructed or what steps would need to be taken to extract the Cd from it in its current state.

I'll take a look at the thread you linked, ninhydric.