Electrochemistry Sulphuric cell.

[jason_recliner]

I used this: http://www.sschemical.com/wp-content/uploads/2013/05/Conversion_Table.pdf
Although on looking at it again I realise I made an error. I accidentally read from the "% 66 Baume" column instead of "% H2SO4". So 78% of 93% acid. Understanding the high concentrations takes a bit of getting your head around for new players!
So my evaporated acid was only ~73%, not ~78%, which is becoming a fair way short of the ideal 85%. No wonder I have a copper powder collection!

 

[Barren Realms 007]

I used this: http://www.sschemical.com/wp-content/uploads/2013/05/Conversion_Table.pdf
Although on looking at it again I realise I made an error. I accidentally read from the "% 66 Baume" column instead of "% H2SO4". So 78% of 93% acid. Understanding the high concentrations takes a bit of getting your head around for new players!
So my evaporated acid was only ~73%, not ~78%, which is becoming a fair way short of the ideal 85%. No wonder I have a copper powder collection!

What were you deplating and how long did you leave it in the cell to deplate the material? I don't think the concentration of the acid is what caused your copper build up.

 

[jason_recliner]

Yes, but the low concentration won't help. I am sure the advice already given is right, that the current was limited to too high a value.

The material I have accumulated is a pile of gold plated Bluetooth stub antennas. The plastic covers rip right off the nut; the steel antenna wire pulls out with pliers. I was only able to deplate about a dozen before my adjustable 40V 5A power supply spat the dummy. I built it 25 years ago from scratch using a magazine design and it has been brilliant until Sunday.

Each test set of 3 was in probably < 5 mins. I was expecting < 10 mins. Some still look like they should run a little longer. I left each set in until they looked like the gold plating was gone or until the current dropped off significantly, however the latter may have been caused by the power supply starting to fail. I really don't know. No more cell work for me until I dig up a 30 year old circuit diagram for an ETI163.

 

[Emmjae]

Here is the company I use to buy my copper mesh. They also carry a lot of other hard to find items.

http://www.mcmaster.com/

Just type in "copper mesh" in their search box and you'll find what you need.

You can purchase a piece as small as 12"x12" or as large as you want.

Regards,

Mike

 

[MarcoP]

Or in U.K. http://www.themeshcompany.com/ that's where I've got mine.

 

[bemate]

This might have been covered already, but I couldn't find any information on it: does the orientation of the cell play a role?

I have no definite plans for any of my scrap yet, but I try to get as much input as possible while I'm still reading and learning.

The reason I ask is simple : I have a sheet of pure copper that would make a great anode (or cathode? Can't remember right now as I have had a few too many at a party...). The thought, drunkenness aside, is to place the plate at the bottom if the cell, connect it to the power supply with copper wire and pile my pins on top in a heap and suspend my lead electrode at the top.

I realize this would make for more work cleaning the pins of black gold dust, but the question is rather if it would affect the efficiency of the cell as opposed to the usual horizontal setup?

 

[FrugalRefiner]

Yes.

Dave

 

[Barren Realms 007]

This might have been covered already, but I couldn't find any information on it: does the orientation of the cell play a role?

I have no definite plans for any of my scrap yet, but I try to get as much input as possible while I'm still reading and learning.

The reason I ask is simple : I have a sheet of pure copper that would make a great anode (or cathode? Can't remember right now as I have had a few too many at a party...). The thought, drunkenness aside, is to place the plate at the bottom if the cell, connect it to the power supply with copper wire and pile my pins on top in a heap and suspend my lead electrode at the top.

I realize this would make for more work cleaning the pins of black gold dust, but the question is rather if it would affect the efficiency of the cell as opposed to the usual horizontal setup?

This would create a problem because the gold that deplates from the material will settle on top of the material and not allow for conductivity to deplate the material. You need to have both the anode (material being deplated) and cathode (lead) suspended in your solution so that the deplated gold can settle to the bottom of the cell. You also need to to make sure they are not separated too far.

 

[nickton]

what does this mean: "In fact, the 50 gallon mild steel tank I used for the solution was made the cathode." ? :mrgreen:

 

[g_axelsson]

He is using the steel tank as cathode instead of having a separate cathode.

Göran

 

[LT_golden]

This is an old thread, and hopefully by now, solar_plasma has found his answer or an equally viable solution.

In case not or if anyone is curious, let's try out catfish's method.

 

[anachronism]

No disrespect but I would rather not. It's horrible stuff to heat to that temperature. You have no margin for error whatsoever.