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Author: Subject: Separation of a US nickel
m1tanker78
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[*] posted on 29-7-2011 at 18:08


Updates: The ammonia complex contains copper ions so this method isn't useful for separating copper and nickel. It does appear to be useful for removing other contaminants such as iron, though (see below). Lowering the current density during my plating tests produced a distinct copper deposit on top of the nickel deposit pictured above. Bummer...

On the flip side, I collected a carefully washed sample of the precipitate that's produced from adding ammonia to the chlorides. I non-destructively dried it by passing a gentle stream of air over it for 2 days or so. I'd previously pyro'd a sample of both products which was what aroused my suspicions of the ammonia technique in the first place.

It's hard to fathom how a tiny pellet (see bottom of shot glass) can make such a voluminous precipitate. The shot glass was literally filled to the brim with the decanted slurry...


What impressed me even more was that the pellet is rigid and retained its shape as it shrunk down. Weird...


I always thought the inside bottom of the shot glasses were perfectly rounded. Obviously, they ain't!...


The pellet is only barely attracted to a strong magnet. The attraction is almost negligible but then, I don't expect there to be much nascent metal or magnetic oxide(s) within.

It's possible that some of the nickel and copper precipitates as *ides along with [God knows what else]. These two metals are a modern-day Romeo and Juliet (so far). **Sings "Love Hurts"**

Now I have that damned song stuck in my head. :(

Tank

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cyanureeves
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[*] posted on 29-7-2011 at 19:44


i tried the salicylic method also and i probably have acetysalicylic because i could not produce copper nor nickel salicylic.salisylic acid supposedly does not combine with nickel carbonate but will with copper carbonate to make copper salicylic. i turned all the nickel/copper chloride solution to the carbonate and added salicylic acid but it all turned baby blue colored and i never got the bright blue insoluble copper salicylic.
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m1tanker78
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[*] posted on 31-7-2011 at 07:47


Reeves,you went straight from electrolyte liquor to the carbonates without an intermediate ammonia step? I'm trying to picture your procedure.

I'm very tempted to try a few things in the molten state (outside!). That's a little far-reaching for academic purposes, though.

Tank

[Edited on 7-31-2011 by m1tanker78]
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cyanureeves
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[*] posted on 31-7-2011 at 10:46


yes tank i just dumped a whole lot of sodium carbonate in the chloric mixture but i think baking soda would've worked better. i dried the carbonates and went on to do the procedure that i saw on youtube to make coppersalicylate by aunonomus. he calls it copper aspirinate. first i made salicylic acid using myfanwy's method with dollar general aspirins which by the way dissolved cleanly as non of it was caught in the filter.myfanwy probably learned how to make salicylic acid here because there is a thread about it here and about copper salicylic,i just used his method because he laid it out on video. i need to make pure copper sulfate before i attempt to make copper salicylic again to see if my salicylic acid is good because my copper sulfate was gotten from epsom salt and copper and probably has alot of magnesium sulfate.

[Edited on 31-7-2011 by cyanureeves]
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[*] posted on 31-7-2011 at 11:08


You can use dimethylglyoxime to separate the nickel from the copper (Ni(dmgH)2 precipitates), although its not very affordable, may be only on small/demonstration scale.

UPDATE- Just read on the German wiki that it forms a complex with copper too, but my question below still stands.

I'm planning to form this complex myself, as I understand, it is used as a solution in ethanol, can acetone replace it?
Also, do I need any special conditions to dissociate the dimethylglyoxime into dmgH- and H+ like a basic environment? Or a dilute solution at neutral pH will also give good yield?

[Edited on 31-7-2011 by Mixell]
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m1tanker78
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[*] posted on 31-7-2011 at 19:06


Reeves, your description sounds analogous to the ascorbic acid method that was proposed (but never attempted AFAIK). I'll look for solubility data and see if it's viable for this purpose.

Mixell, I never used DMG. Like you said, it reacts with both metals so it would be back to square one.

It appears that both metals form a carbonyl complex as well. Yet another dead end on a dangerous path. Ni(CO)4 is very toxic, flammable and volatile even at room temp. Everything I'd ever want in a metal complex (NOT). I won't lie, it IS tempting.

So far, the most success I've had is in dummy plating the copper (sponge) while electrochemically dissolving the metals. This procedure removed a significant amount of copper from the cell liquor and dissolved the coins in relatively short order. Still, I'd have to find a way to remove the remainder of the copper before I can call it 'doable'. Switching to a graphite anode toward the end should allow me to continue with removing copper without introducing more metal ions. If the anode happens to shred a little, filtration will remove the carbon fluff.

Tank

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[*] posted on 1-8-2011 at 01:15


What about iodide ions to precipitate the copper as CuI (Cuprous iodide, the decomposition of the extremely unstable CuI2, which serves as an intermediate in this reaction) Ni2+ should stay in solution, because NiI2 is stable.
All according to Wikipedia, but it seems right.
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m1tanker78
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[*] posted on 3-8-2011 at 12:20


I'm iodine-poor so someone else will have to experiment with that. It'd be interesting to see it work experimentally. H2S is another one that would be reserved for a more dire situation.
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[*] posted on 17-10-2011 at 20:48
Illustrated follow-up


My method of simultaneously dissolving US nickels (coins) and reducing out Copper(I) by electrolysis appears to have produced satisfactory results. HCl was the acid of choice for that experiment - cheap and available. Like most of my 'successful' experiments, I used my senses to make adjustments.

After it was all said and done, I had some concentrated nickel chloride solution with which I could perform some simple tests.
Below is a small sample:


After adding aluminum, the nickel 'crashed' out of solution and left a sludgy mess.


Sludge after drying:


Easily crushed to a fine powder:


Nickel powder influenced by a magnet (underneath):




Copper residue recovered from the process:


I'll try to reproduce this soon and note down voltage, current, temperatures, procedures, so on. Not bad for having started with 75%/25% Cu/Ni.

Tank
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[*] posted on 18-10-2011 at 15:49


congratulations! can't wait til you write up the whole process. google this very same thing and you'll see a whole bunch of theory but hardly anyone shows proof.
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[*] posted on 18-10-2011 at 15:54


I second cyanureeves, that is nifty.
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m1tanker78
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[*] posted on 23-10-2011 at 08:33


I dissolved a single nickel several months ago in concentrated HCl + 18% hydrogen peroxide. I don't know how long it took because I flat out forgot about this one. I had to add distilled water and a bit of HCl to redissolve the solid. It should have been roughly 3/4 copper and 1/4 nickel. I used aluminum metal to drop out the metal powders.

The experiment revolved around using a magnet to separate the dry, powdered metals. All attempts of doing so were unsuccessful. I tried dragging the nickel powder up with the magnet and tapping off the copper. I also placed the magnet on the cap of the container and gently shook. This method alone would constitute an unacceptable loss of nickel in each 'purification' step and will still have too much copper mixed in.

This would have made the electrolytic process much more hands-free but it didn't work out. I should have some free time today so I'll make another electrolytic batch and take some notes and pics.

Tank
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[*] posted on 23-10-2011 at 09:26


The acid of choice for both Cu and Ni is nitric acid. If you haven’t got any, try HCl + NaNO3. HCl alone is a slow boat to China for both.

To separate the precipitated metals purely on magnetism is a pipe dream, IMHO. The metal powders are too intertwined and there may have been some coprecipitation too, making good separation difficult. It’s a recipe for very impure Ni and very impure Cu, both of which would then need refining anyway.

Separation by sulphides is highly efficient but smelly.

Perhaps you could try taking advantage of Cu’s amphoterism? Cu(OH)2 does dissolve appreciably in strong NaOH/KOH, forming cobalt blue cuprate [Cu(OH)<sub>4</sub><sup>2-</sup>] anions. Ni(OH)2 does not. At 75/25 Cu/Ni that would take a lot of NaOH though…




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m1tanker78
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[*] posted on 23-10-2011 at 10:35


Quote: Originally posted by blogfast25  
The metal powders are too intertwined and there may have been some coprecipitation too, making good separation difficult. It’s a recipe for very impure Ni and very impure Cu, both of which would then need refining anyway.


That's precisely what I observed. I was trying to get around having to scrape the Copper(I) Oxide (and/or hydride?) off the cathode every hour or so. Aside from that, the electrolytic separation of the metals seems to work well. I'm working on starting another batch as I type...

Tank
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[*] posted on 23-10-2011 at 14:04


Quote: Originally posted by m1tanker78  
Sedit, the magnet test (which I forgot about) will be useful once I remove iron from the mix. Thanks for the suggestions. Just to clarify, you precipitated nickel powder from an acidic solution of nickel chloride with aluminum, right? Seems easy enough for a qualitative test for nickel...

+++++++++++++++++++++++

I dried a sample of the freshly prepared carbonate (same as the pic I posted before). For clarity, this carbonate is prepared from the ammonia complex, not from the original precipitate.


Although the image is crap, the powder bears a striking resemblance to 'the real deal', nickel(II) carbonate. Then, I'm reminded, "Don't judge a chemical by its color."

So what's better here, acetate for a plating test or chloride then reduce with Al for a magnet test? It's probably too little to practically plate anything except maybe the tip of a copper wire or similar. I have ~ 500mL of cell liquor left from this batch.

Tank





I haven't abandon you in your quest Tanker just been very busy. Its glad to see your making progress.

In reply to your quote may I offer another suggestion, Covert the carbonate powder you have to the respective chlorides and heat it till its anhydrous, Copper contamination will show a brown color where as anhydrous Nickle will be yellow. It should give you some idea if there is Cu in the mix to some extent.

I need to get on the ball repeating this experiment and documenting it completely just so back up my claims but like I stated before time has not really been on my side. That magnet test should be the most productive as far as determining the amount of Ni present but will not exclude excess Cu from carrying over into the magnetic particles. Me and Vesp tried in the past to use a magnetic stirrer to separate the two after precipitation but it proved relatively useless due to the small particle size. I may right more later when I get a chance but I just wanted to let you know I am still here watching along so when I get a chance to repeat I will offer more information as to the process I toyed with sometime ago on precipitating just the Ni out of the Cu/Ni complex.

Good to see someone more motivated then myself in this experiment, carry on the good work.
~Sedit





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m1tanker78
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[*] posted on 23-10-2011 at 15:11
The Anode:


A late start; I tack welded 17 nickels together in the form of a fly swatter. The total starting mass is 84.2g:


It's important to make sure the welds penetrate all the way though so that there's good conductivity even as the anode erodes. Back side:


I used a sharpened graphite gouging rod - DCEN - Poor man's TIG :D

More to come...

p.s.: Sedit, glad you're following along.

Tank
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[*] posted on 23-10-2011 at 18:35


I just noticed something that may be of value to someone more apt then me in chemistry and I feel it has to do with the common ion effect of some sorts.

I mixed H2O2 and H2SO4, added 15 USA nickles and after a few hours noticed a shit load of CuSO4 precipitating with a green solution on top.... No evidence of precipitated Nickle sulfate has shown itself only the Copper sulfate.

Anyone care to elaborate on what I can't fully explain?


PS: I have seen this before with the sulfate however the green solution still contains SOME Cu salts yet much has been precipitated already so it may aid in separation in one form or another.

[Edited on 24-10-2011 by Sedit]





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m1tanker78
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[*] posted on 23-10-2011 at 18:56


Sedit, I noticed the same thing:



Look familiar?? hehe
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[*] posted on 23-10-2011 at 21:28


VERY!.... Make that Exactly!

Reduction with Al proved there is still Copper ions in there but it is obvious much has precipitated. Im running it with Aluminum in a magnetic stirrer as we speak but there is still a significant amount of Copper present in the green solution.





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[*] posted on 24-10-2011 at 04:46


Quote: Originally posted by m1tanker78  
A late start; I tack welded 17 nickels together in the form of a fly swatter (...)
Tank


What type of electrode are you using? Tungsten? Titanium? Iron?Wouldn't this welding introduce another metal impurity to your solution? Even carbon arc electrodes have a copper shielding that would alter the metals present in your nickel anode...

Robert




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[*] posted on 24-10-2011 at 04:48


Both:

You've obviously exceeded the solubility limit of CuSO4 in your solvent, the excess of which crystalised out, but not the solubility limit of NiSO4 which remains in solution in its entirety: partial separation! Naturally the supernatant liquid is saturated with CuSO4 but it won't be that much, going by colour. There must be some common ion effect going on here.

Precipitate the supernatant liquid as mixed hydroxides, then treat with hot, stronng NaOH to leach out the copper as cuprate and Bob should be your uncle!

For the CuSO4, wash with cold water, then recrystallise once to get relatively pure copper suphate pentahydrate...

The FBI should now be onto both of you for destroying legal tender! :D

[Edited on 24-10-2011 by blogfast25]




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m1tanker78
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[*] posted on 24-10-2011 at 06:23


Quote: Originally posted by Arthur Dent  
What type of electrode are you using? Tungsten? Titanium? Iron?Wouldn't this welding introduce another metal impurity to your solution? Even carbon arc electrodes have a copper shielding that would alter the metals present in your nickel anode...


Hi Robert, the copper cladding on gouging rods can easily be peeled or etched off. Our nickels contain 75% copper - of which >97% will be electrolytically removed so copper is hardly a contaminant. I didn't use any filler metal to tack the coins.

Tank
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[*] posted on 24-10-2011 at 06:42


I think you're safe as far as the legal tender issue goes - Title 18, United States Code, 331 says only that it is illegal to "fraudulently" mutilate coins.

On the other hand, deliberately rendering a bill unfit for use does appear to be illegal, under Title 18, United States Code, 333.

Not legal advice, just one of those bits of trivia that accumulates after a while, thought it might be worth passing on.
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[*] posted on 24-10-2011 at 06:51


The experiment is coming along nicely. I was afraid I'd develop the 'scaling up blues' but that hasn't been the case. Unfortunately I'm going to have to interrupt the electrolysis experiment until I get back home. I'll leave a few pics showing the progress and fill in details this evening...

The cell:


"First fuzz" and a hint of tint:


Just before the first cathode scrape:



What it looks like now. Nice emerald green:


Anode has thinned considerably (hard to see in the pic):


Stay tuned..

Tank
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[*] posted on 24-10-2011 at 08:52


Now that's what I call copper!

So you're selectively plating out the copper on a steel cathode, while the nickel enters into solution, as NiSO4 right?

What's the electrolyte... dilute H2SO4? And what voltage and amps are you reading?

Very interesting, Tank, much more so than the 'magnetic effort'...




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