I had another go at electronic scrap gold recovery,
the first stage was a soak in nitric acid to dissolve most non-gold metals,
I expect this solution, (which has the blue of copper nitrate solution, is clear and has no sediment)
to contain water, nitric acid and nitrates of
Copper, Nickel, Tin, Iron, Lead, Silver, Manganese, in order of concentration.
I would like to see how many of these cations I can separate, as simply as possible,
One method may be crystallization by evaporation
but I have no idea which would crystalize out first
or even what complex salts may crystalize out.
I will try this but how can I predict what will crystalize out in what sequence,
given that I do not know the relative quantities of cations,
and even if I did, I don't know where to start.
I will also try gentle electrolysis with slowly increasing applied voltage and see what plates out in what sequence.
ANY constructive advice welcome, this is actually more complex than I first imagined.
PHILOU Zrealone - 6-2-2016 at 03:59
Cementation with increasing redox potential metals could do the job but you need specific metals in pure state.
Example, you have Ag(+), Cu(2+), Ni(2+)
1°) Add Cu --> Ag precipitates while Cu dissolves as Cu(2+)
2°) Add Ni --> Cu precipitates while Ni dissolves as Ni(2+)
3°) Add Al --> Ni precipitates while Al dissolves as Al(3+)Sulaiman - 6-2-2016 at 04:49
Thanks, but it sort of requires a pre-knowledge of what is in there, may add new cations and looks tedious,
I think that electrolysis will be easier to be selective ... tbdPHILOU Zrealone - 6-2-2016 at 09:50
Thanks, but it sort of requires a pre-knowledge of what is in there, may add new cations and looks tedious,
I think that electrolysis will be easier to be selective ... tbd
You wrote:
"I expect this solution, (which has the blue of copper nitrate solution, is clear and has no sediment)
to contain water, nitric acid and nitrates of Copper, Nickel, Tin, Iron, Lead, Silver, Manganese, in order of concentration."
So implicitly you were supposed to know what is into your solution...
Electrolysis will be as problematic as cementation (if not more) if you dont know for sure what is in the solution to electrolyse and in what
proportion...because cementation stops when all cations more oxydant than the "saccrificial" metal are reduced. Electrolysis may go further and allow
side reactions with the anions or with the solvent...
