Film on my Cell Cathode slowing my process

[joehast]

I keep getting a brownish film collecting on my lead cathode which in turn slows down my reverse electroplating process. I have been wiping it off with paper towels, however before I discard this I want to know if this is just a copper waste product, or gold.

Could this be caused by using too much Glycerin.?

 

[butcher]

I have not used the concentrated sulfuric stripping cell, the metals are positive, the cathode is negative, so the positive metal ions migrate in solution will move to the cathode and reduce to metals, at same time the sulfate ions move to the anode, to oxidize (remove electrons from metals). this brown on cathode they can be gold or copper I do not know, but can easily be tested, I think I would not wipe them off cathode with paper towel, I would maybe rise of in water that I may use later for rinsing, a tooth brush might help, I am not even sure I would remove them as they will not adhere too much and removeing them later when done with cells processing and the cell is loaded and cleaning out then would probably be best, someone here with expierienc with the cell should clear this up for you.

 

[lazersteve]

It has been stated by GSP and confirmed by myself and many others that Glycerin is not required.

From the looks of your very black acid, either your cell is saturated or you are using liquid fire drain opener or a similar one which contains buffers. These buffers can cause strange foaming and deposits.

What was your original source of acid and how much scrap had you processed at the point the photo was taken? The type of scrap may also be a clue as to what the deposit is.

Steve

 

[joehast]

Rooto brand drain opener. I haven't processed all that much really. In the past I haven't had trouble w/ Rooto.

 

[lazersteve]

I routinely use Rooto and have not had any problems either.

Perhaps it is coming from the scrap or your positive lead?

Steve

 

[Harold_V]

A drop of AR on the brown deposit, still on the paper, then a test with stannous chloride might reveal what you're seeing. If the AR yields a yellow solution, it's likely gold. It it's green, it could be gold and copper. A test with a drop of nitric should eliminate all of the deposit if it's copper, but will leave some behind if there's gold.

Testing is key to learning.

Harold

 

[joehast]

Thanks Guys. I have no stannous chloride, and the closest thing I have to Nitric is one of the bottles in my Gold scratch test kit. I will try to determine content with Nitric.

 

[butcher]

do you have tin solder and muratic acid?

 

[Anonymous]

I can not understand why a film on your cathode would slow the process. Doesn't all the important stuff happen at the anode?
Jim

 

[Harold_V]

Thanks Guys. I have no stannous chloride, and the closest thing I have to Nitric is one of the bottles in my Gold scratch test kit. I will try to determine content with Nitric.

Please take this in the spirit in which it is offered.

One does not refine gold without stannous chloride, no more than one drives on the freeway when blind.

You should study Hoke, where you can learn how to do meaningful tests.

Harold