goldberg
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Nickel from NiCd batteries
I tried to search for this thread but did not managed to find one.
If i did not searched hard enough then sorry for that.
I have old NiCd battery and i would like to harvest nickel and cadmium from it.
Battery is rather broken and unusable as source of elctricity.
I read that in charged battery there is NiO(OH) and metallic cadium.
During discharge both metals are converted to their hydroxides.
I would like to have nickel in form of nickel (II) chloride or nickel (II) acetate.
I do not have any hydrochloric acid so i am intrested in making nickel (II) acetate.
I did not managed to find much information about NiO(OH) properties.
I'm thinking about following procedure: Charge battery as much as possible to convert both metals to NiO(OH) and metallic Cd, then dissassemble
battery, remove cadmium eletrode. Then get NiO(OH) eletrode put it into jar with NaOH solution (what concentration?) insert graphit rod as second
eletrode and apply DC voltage to convert NIO(OH) to Ni(OH)2. Then filter off nickel (II) hydroxide and treat it with excess of acetic acid. Solution
should become green. Then evaporate all water and rest of unreacted acetic acid and purify nickel (II) acetate by crystallisation.
Does it makes sense or have i missed something?
Alternatively i could maximally discharge battery, then apply some reversed DC volatage to make sure that both metals became hydroxides, disassemble
battery, add exess NaOH to make cadmium complex, filter off nickel (II) hydroxide and process as written above. Then separate cadium complex by
crystallisation. But i prefer to have cadium in metallic form.
Have anybody tried such thing? Most discution there is about dissolving nickel coins what seems to be tricky in practice.
Also should i store metallic cadium under naphta like sodium to prevent oxidation?
I know that this can be overkill but it seems to be easy and cheap way to store this metal.
Unfortunately i do not see a way to check if all NiO(OH) became nickel (II) hydroxide.
Any ideas how i can check that?
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clearly_not_atara
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Can't you find a battery that doesn't contain Cd to play with? Seems an unnecessary risk.
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fusso
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Maybe he wants to
save the Cd for future use before NiCds are banned in his country?
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RogueRose
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Maybe he wants to make yellow paints at some point?
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Sulaiman
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PLEASE CORRECT ME IMMEDIATELY IF WRONG
I can see the logic of grouping cadmium with lead, mercury and others from an environmental point of view,
but for an amateur chemist I'd think that it is less toxic than most heavy metals (or heavy metal salts).
So if reasonable precautions are taken,
I (personally) would not be too concerned with toxicity issues
- except for disposal.
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RogueRose
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To the OP, I'm with you in trying to figure out a good method of seperating the two. I have plenty of NiCd's to work with (unlimited amount if I
wanted). The biggest challenge is getting them open, I hate cutting the outer steel case.
I did find something interesting though you might want to pursue. NiSO4 heptahydrate is soluble in "alcohol" as per Wiki. Now if that is ethanol or
not IDK and to what degree (hopefully highly soluble), but CdSO4 is insoluble in ethanol and only slightly soluble in methanol.
So if you can convert the two to the sulfates (H2SO4 + H2O2 maybe?) and then use the ethyl alcohol (anhydrous I would try) then you have a way to
seperate the two metals.
IDK where you live but maybe you can find someone or some place that is getting rid of old NiMH batteries and then you would not have to worry about
the cadmium. NiMH batteries are more rare though.
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fusso
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Quote: Originally posted by Sulaiman | I can see the logic of grouping cadmium with lead, mercury and others from an environmental point of view,
but for an amateur chemist I'd think that it is less toxic than most heavy metals (or heavy metal salts).
So if reasonable precautions are taken,
I (personally) would not be too concerned with toxicity issues
- except for disposal. | I've always thought of Cd being more toxic than lead:O
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goldberg
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I'm aware of dangers of cadmium. I am intrested in NiMH too but i would like to get some cadmium too.
I'm going to process what i will get and right now i have a few NiCd batteries.
Unfortunately i do not have H2SO4 and HCl and i have no source of them. This same for H2O2 above 3%.
Does my idea of converting NiO(OH) to nickel (II) acetate makes sense?
I did not managed to find any information about properties of NiO(OH).
Ethyl alcohol does not dissolve typical salts and i do not see why it would dissolve NiSO4.
I'm wondering what concentration of NaOH i should use for electrolysis that will convert NiO(OH) to Ni(OH)2 and how
to monitor this reaction. Should nickel (II) hydroxide fall of to bottom of electrolysis cell or what i should expect?
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CarlSagans_RayGuns
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Most of the time I find the NiO(OH) is a powder embedded in a nickel metal mesh that's nearly impossible to separate. Using hot HCl is by far the
easiest way I have found. Opening fully charged batteries can be really dangerous, be careful! If you short them out they will be glowing red in a
matter of seconds. Burning through your hand, table or whatever you drop them on when it happens.
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Ubya
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i am also planning on getting nickel and cadmium from NiCd batteries (and NiMH). i had your idea of charging the battery to get metallic cadmium, but
when i dismantled the cell there was only a paste and a paste on a metallic mesh(i hoped it would be cadmium, so i heated it with a torch, cadmium has
a low melting point, this mesh didn't so probably is nickel), probably the "paste" has the cadmiun. more informations are needed
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elementcollector1
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From previous experience, they put the Cd metal as a gray, paste-like substance covering the steel mesh. You can scrape it off with little difficulty,
but melting it is a little trickier - I eventually found that a steel crucible, propane blowtorch, and a small amount of NaOH as flux worked.
Melt only larger amounts, and be sure to use flux - it will only oxidize otherwise due to small particle size.
Elements Collected:52/87
Latest Acquired: Cl
Next in Line: Nd
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Ubya
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Quote: Originally posted by elementcollector1 | From previous experience, they put the Cd metal as a gray, paste-like substance covering the steel mesh. You can scrape it off with little difficulty,
but melting it is a little trickier - I eventually found that a steel crucible, propane blowtorch, and a small amount of NaOH as flux worked.
Melt only larger amounts, and be sure to use flux - it will only oxidize otherwise due to small particle size. |
thank you for the tip, tomorrow i'll harvest some cadmium paste
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goldberg
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Thanks for information about form of nickel.
So if i have metallic nickel + NiO(OH) so maybe discharge maximally battery, then apply reverse voltate to make sure that reaction was driven to
completion. Then open battery, put everything into baker, add NaOH solution. Cadmium hydroxide will be complexed so filter it off.
Then treat residue with acetic acid. Nickel hydroxide will be converted to nickel acetate filter it and done.
Then we will have metallic nickel. How about eletrolysis of sodium carbonate solution with nickel as anode and graphite as cathode?
Nickel will dissolve as Ni2+ ions and they will react with sodium carbonate and fall of as nickel carbonate solution before reaching cathode?
Ofc. significant amount of sodium carbonate will be destroyed by electrolysis but nickel is worth much more that sodium carbonate.
Or even better: use electrolytic divider and use sodium carbonate as catholyte and something other for anolyte so there will be no risk of getting
sodium hydroxide that will react with Ni2+ to form nickel hydroxide.
What do you thing about this rotue?
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XeonTheMGPony
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Cadmium is very toxic, it goes after kidneys liver, be very diligent in your work with it, gloves and mask
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goldberg
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I am aware of that and i will protect myself.
How about disposal of waste, any sugestions?
And could someone, please verify my reasoning about planned route of getting nickel salt?
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Ubya
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i don't have any informations about NiO(OH).
to complex Cd (OH)2 back in solution you need a PH of >11, so NaOH is better
[Edited on 13-11-2018 by Ubya]
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fusso
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Use Na2S to ppt CdS, then roast to form CdO, and dissolve in
acid of your choice to reuse them. I'd keep them since I don't know whether my gov will ban it soon. It's best to obtain/hoard chemicals while you
still can.
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goldberg
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Cadmium hydroxide is not amphoteric so it will not react with NaOH to give water soluble complex.
Eletrodes are physically separated so i can just dissassemble battery and substances on both electrodes will not be mixed so separation will
be esasier. I will try to maximally discharge battery (charging is not good option because i will be dissassembling dead ones...) and try to tread
Ni(OH)2 with 10% acetic acid and see if solution will become green...
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FluoroPunch
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Hey guys, I'm joining the bandwagon to extract cadmium haha. Did you guys have any luck so far?
A few notes I'd like to add:
-Cd(OH)2 does slightly dissolve in excess alkali (not much though), but Cd(OH)4 2- can be formed
-You should definitely wear a particulate filter since CdO is produced when the metal vaporizes
-It IS more dangerous than the other heavy metals since it can vaporize more readily
Does anyone know any more of the specifics of charging a NiCad battery? From what I've read they should not be overcharged/undercharged since this
will affect their capacity - likely the quality of the metal that can be recovered will be affected too.
Here's pretty much the only videos on Youtube where someone actually takes apart a cadmium battery:
https://www.youtube.com/watch?v=w3RedyFDOO4
https://www.youtube.com/watch?v=KMiJ_ZNIk7A
https://www.youtube.com/watch?v=vPYT4kY7pao
Surprisingly more than before...
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charley1957
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Cadmium from NiCd batteries
I've also gone down this path to obtain cadmium. I removed the nickel screen from the battery and placed it under a little distilled water, and
scraped the screen clean. The scrapings, I assume, are cadmium, and I've got several teaspoons full of the stuff under water. I tried melting some
down, but as mentioned above, it only oxidizes. I'll have to try fluxing. The process is time-consuming and tedious, but it does work. The water
keeps the scrapings from flying everywhere, and I read somewhere that the cadmium was so fine it might be pyrophoric. Anyway, gloves are mandatory as
are goggles. Good luck!
You can’t claim you drank all day if you didn’t start early in the morning.
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