electrokinetic
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Reducing Cu and Ni with Zn
I read a blurb online about how zinc will not reduce nickel ions even though Zn is above Ni in the potential series.
https://www.nature.com/articles/142210a0
I thought this might be a useful way to separate copper from nickel, but I can't find any mention of it searching through the threads on that topic.
I decided to do a test and share what I did for feedback.
Here are two test tubes. The one on the left contains 1 mmol of CuSO4 and the one on the right contains 1 mmol of Ni2NO3.
Here are the same two test tubes one day after a slight excess of Zn dust was added.
The Cu test tube looks like all the Cu has reacted. To make any Cu ions more visible, I added 5 drops of 30% NH4OH. Here is a pic right after adding
the ammonia before shaking,
and after shaking.
Am I right to conclude that the lack of visible blue means all the Cu has been reduced?
To see if any of the Ni was reduced, I used a neodymium magnet to try and move around the solid material in the Ni test tube. Here are pics I took
while moving the magnet around the solid material. They're not the best pics because I twisted the tube between pics, but it was clear to me the
solid material didn't move at all.
I think the next thing I'm going to do is try to plate the nickel out of solution. I'll update the post if I do.
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Fluorite
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You can also use aluminum to reduce nickel metal The reaction is not vigorous as with copper compounds but it happens
To see if there's any copper ions left in the solution you can bubble hydrogen sulfide or use sodium or ammonium sulfide to precipitate dark copper
sulfide, zinc sulfide is white so it should not be a problem
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S.C. Wack
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Zn reduces Ni salts, perhaps not quantitatively under all conditions or to pure Ni...with evolution of hydrogen...search term: Urushibara
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electrokinetic
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Quote: Originally posted by Fluorite  | You can also use aluminum to reduce nickel metal The reaction is not vigorous as with copper compounds but it happens
To see if there's any copper ions left in the solution you can bubble hydrogen sulfide or use sodium or ammonium sulfide to precipitate dark copper
sulfide, zinc sulfide is white so it should not be a problem |
Does the aluminum require any specific anion present to reduce the nickel? For example, aluminum foil put into copper sulfate won't do anything until
chloride ions are added.
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symboom
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Not sure but I dissolved some pennies in peracetic acid and I'll deffinatly try the zinc trick to get the copper out
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njl
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Seeing as how many coins are simply a nickel/copper alloy, this might be a nice way to extract nickel from them.
Reflux condenser?? I barely know her!
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Bedlasky
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Nickel react better with zinc or aluminium in the presence of chloride ions. Reaction is very fast and very exothermic (when I made nickel metal using
aluminium and NaCl, reaction was so exothermic that I must cool the mixture). Nickel made by this way isn't pure even after several hours in
concentrated NaOH (mine is 93,5% or so).
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electrokinetic
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It is interesting that the Urushibara article specifically named NiCl2 as the nickel salt in the preparation of nickel using zinc.
Urushibara
What I am going to do tomorrow is add some chloride ions to the nickel nitrate test tube and report back what happens.
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electrokinetic
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| Quote: Originally posted by Bedlasky | | Nickel react better with zinc or aluminium in the presence of chloride ions. Reaction is very fast and very exothermic (when I made nickel metal using
aluminium and NaCl, reaction was so exothermic that I must cool the mixture). Nickel made by this way isn't pure even after several hours in
concentrated NaOH (mine is 93,5% or so). |
Educate me please, what does the NaOH do purification-wise?
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S.C. Wack
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There is mention of using the sulfate in the related literature but it is generally not used for reasons which I haven't seen explained. The sulfate
absolutely reacts...nitrate could possibly be reduced to ammonia.
[Edited on 26-4-2021 by S.C. Wack]
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Bedlasky
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NaOH remove leftover aluminium. Al react with NaOH to form [Al(OH)4]- and H2 gas. Nickel doesn't react with NaOH.
Chlorides help to proceed the reaction because of dissolving Al2O3 protective layer on the surface of aluminium (formation of [AlCl4]-). For zinc it
is similar.
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electrokinetic
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| Quote: Originally posted by Bedlasky | NaOH remove leftover aluminium. Al react with NaOH to form [Al(OH)4]- and H2 gas. Nickel doesn't react with NaOH.
Chlorides help to proceed the reaction because of dissolving Al2O3 protective layer on the surface of aluminium (formation of [AlCl4]-). For zinc it
is similar. |
Jesus Christ, I can't believe I had to ask that—I've used that reaction to make hydrogen for fire balloons. Thanks for clarifying though.
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electrokinetic
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Here is the test tube a day after adding ten drops of saturated sodium chloride solution. There appears to be no change:
Right after adding a strip of aluminum foil:
And then 3 days later, where there does seem to be some cloudy material near the bottom. Test with a magnet for nickel was negative:
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