Sciencemadness Discussion Board

How to [recover] dissolved in acid Tin

Romix - 7-6-2024 at 15:40

Hello again Dear forum members.
Any literature you could recommend?
Or maybe you have experience?
Displaced Tin out of solution with Aluminium, not melting.
Any ways of recovering it from solution as metal in bars?


[Edit by mod]
Title change for clarification.
(Replaced "melt" with "recover")

[Edited on 8-6-2024 by j_sum1]

[Edited on 8-6-2024 by Romix]

bnull - 7-6-2024 at 15:50

Did you try electrolysis?

Romix - 7-6-2024 at 15:52

Quote: Originally posted by bnull  
Did you try electrolysis?

Not yet.

Rainwater - 8-6-2024 at 03:56

You can try cementing the tin out of solution with a more reactive metal such as iron or aluminum.
The results will vary based on ph and the exact composition of the solution.
Here is some reading explaining the reaction
https://chem.libretexts.org/Courses/Oregon_Institute_of_Tech...

[Edited on 8-6-2024 by Rainwater]

j_sum1 - 8-6-2024 at 04:42

Electrolysis of tin solutions is very easy.
Only a couple of issues I can think of. If the solution is too acidic, the crystals can redissolve quickly when the voltage is turned off. Also, the tin crystals grow quickly enough that you could have shorting problems.

Sulaiman - 8-6-2024 at 07:42

As above, tin electrolysis is super easy,
Blatant promotion of my own video (real time)
https://www.youtube.com/watch?v=G1sq4hnrBgM

At low current densities you may be able to plate a cathode,
putting your recovered metal, connected as an anode, in a membrane.
Sreetips silver cell on YouTube comes to mind.

PS
What kind of volume are you dealing with?
What acid, tin concentration in solution, contaminants?
Have you processed all with Al, or just a sample?


[Edited on 8-6-2024 by Sulaiman]

Romix - 8-6-2024 at 11:31

Quote: Originally posted by Sulaiman  
As above, tin electrolysis is super easy,
Blatant promotion of my own video (real time)
https://www.youtube.com/watch?v=G1sq4hnrBgM

At low current densities you may be able to plate a cathode,
putting your recovered metal, connected as an anode, in a membrane.
Sreetips silver cell on YouTube comes to mind.

PS
What kind of volume are you dealing with?
What acid, tin concentration in solution, contaminants?
Have you processed all with Al, or just a sample?


[Edited on 8-6-2024 by Sulaiman]

Sample!

Sulaiman - 8-6-2024 at 23:18

Two options; (assuming HCl is the acid)
Electrolysis of the bulk liquid, graphite anode?
HCl and Cl2 gasses may be evolved.
Slow (low over-voltage) plating will minimise electrodeposition of other metals.

Al replacement then heating above 180 C to sublime off the aluminium chloride,
turn up the heat, add a little borax, and melt your tin.
(try some borax with your existing processed sample)
EDIT: this is wrong based on an incorrect assumption of mine. See Rainwater's post below.

[Edited on 9-6-2024 by Sulaiman]

chornedsnorkack - 8-6-2024 at 23:37

What is the pH range where tin precipitates as metal on cathode?
Too low pH, and cathode will reduce H2, not Sn
Too high pH, and Sn precipitates as Sn(OH)2.

Rainwater - 9-6-2024 at 02:11

Quote: Originally posted by Sulaiman  

Al replacement then heating above 180 C to sublime off the aluminium chloride,
turn up the heat, add a little borax, and melt your tin.

That will only work with anhydrous AlCl3 once the Al is dissolved in water, it changes.... maybe the word is complexes...... with water forming [Al(H2O)6]Cl3. Heating over 100c will release water and HCl, leaving a mixture of Al hydroxide and oxides.

bnull - 9-6-2024 at 06:10

@Romix: How much tin are we talking about? What acid did you use?

If you're not in a hurry, you may try this: neutralize the excess acid with sodium carbonate; sandpaper the interior of a paint can or other disposable steel container; attach a piece of aluminum to the outside of the can by means of a copper wire; fill the can with the solution and immerse the aluminum piece on it (don't let it touch the bottom). It will take some time, it is boring as hell to watch any length of the process, and I only resort to that when I don't want to electrolyse stuff.

Romix - 9-6-2024 at 19:06

Sorry guys, too many of you asked too many questions all at once, I'm confused.
Displaced Sn with Al out of Chloride, yes, metal isn't melting!
I'll leave a piece of 99% plumbing solder in HCl for few months then will electrolyse solution and try melting after.
Volume from small experiment up to buying tons of PCBs dirt cheap and processing them. Legally or not...
Pewter is also an interesting alloy.



[Edited on 10-6-2024 by Romix]