BlackDogSociety - 15-6-2012 at 07:28
Greetings everyone, this is my first post and I'm a beginner, as you will soon see 
. Ok I put some nickel coins in Muriatic Acid (31% HCl) and in a couple of minutes the solution started turning yellow. I presume that the nickel
is changing to nickel chloride. This process seem to be taking a long time so added some H2O2 to speed up the reaction. It worked but the solution
change to a green color. I guessing that was due to the copper content in the coins. Yeah adding the H2O2 probably wasn't a great idea, anyway...
I left it for a couple of days then I decided to put some Sodium Carbonate (A & H Super Washing Soda) to precipitate out the carbonates. I realize
that I have no idea how much to use so I started adding the Na2CO3 slowly stopping when the bubbling stopped. Upon filtering the solution I thought
I'd be left with a water clear solution of NaCl but the solution is clear but a dark shade of blue, as dark as the copper acetate I've made before.
What could this solution be?
Pyro - 15-6-2012 at 08:16
no idea, but do you have your carbonate? if so just dump the solution 
BlackDogSociety - 15-6-2012 at 08:54
Yeah, I have the carbonate. It just such an intense blue color that it must contain a lot of copper in it. Is there a way to determine what it is and
recover it?
[Edited on 15-6-2012 by BlackDogSociety]
cyanureeves - 16-6-2012 at 05:21
add ammonium hydroxide to it and see what you get then take your results to the separating nickel from coins thread,you'll be in for i a ride i think!
[Edited on 16-6-2012 by cyanureeves]
bbartlog - 16-6-2012 at 13:53
Na2CO3 is basic enough that some of the copper may be solubilized as cuprate (which is deep blue just as you describe). You probably overshot somewhat
when adding Na2CO3. You could try adding HCl dropwise with stirring to see whether the intensity of the blue diminishes; if it does, then that's your
answer and you just need to lower the pH to somewhere close to neutral to precipitate out the cuprates.