kernels - 18-1-2018 at 01:55
Hi there, brand new member here, engineering background and only a little bit of experience with chemistry.
I have two questions that I hoped you guys and gals may be able to help with:
1 - What is the difference between electrowinning and electrolysis, it appears that with both you apply a voltage between two electrodes in a solution
and split molecules with oxidation and reduction happening at the electrodes.
2 - What determines the order that various metals will plate out of a solution in ? Assuming the solution contained Cu, Sn and Fe chlorides together
with HCl
Greatly appreciate any information, or even just a pointer at where to look to find the answer.
Thank you
brubei - 18-1-2018 at 02:21
Yes it the same, the reactions with higher potential difference will happen first.
wg48 - 18-1-2018 at 03:26
1, Electrowinning uses electrolysis to separate metals or purify them.
So electrotwinning is electrolysis but not all electrolysis is electrotwinning.
2, The electrochemical series relative to the voltage between the electrodes prinicpaly determines which metals if
any may be deposited.
kernels - 18-1-2018 at 16:34
Thank you guys for the insights
elementcollector1 - 18-1-2018 at 20:08
To clarify, electrowinning refers to the large-scale recovery of a bulk deposit of a metal from a solution, usually as a means of production.
Electrolysis, on the other hand, is any process that uses electrons and an electrical current to split a compound into two or more new ones.
Cu, Sn and Fe, if I recall correctly, are all pretty far apart on the electrochemical series, so you shouldn't have much trouble with them so long as
you keep your voltage well-controlled during each experiment.
One thing I noticed during my work with selective electrodeposition is that solutions with low pH have an unfortunate habit of dissolving your
electrodeposited metal right back off the electrode until the acid is depleted. In HCl's case, I would recommend heating somewhere outside to drive
off HCl fumes and push the pH back towards something that won't eat your deposit alive.
symboom - 19-1-2018 at 00:31
I got an interesting question if aluminum is placed in a copper nitrate, lead nitrate and silver nitrate what will happen all metals displaced at once
or just the least reactive such that silver is displaced out then lead followed by coper