Electrochemistry Sulfuric acid cell

[Axlrod2]

I finally got my reserve electroplating cell to work. I got a good white bubbles from the neg lead side but it does not last long till the power supply shorts out. Why? Should I use a battery charger? Use a bigger, longer dish?

 

[NobleMetalWorks]

I finally got my reserve electroplating cell to work. I got a good white bubbles from the neg lead side but it does not last long till the power supply shorts out. Why? Should I use a battery charger? Use a bigger, longer dish?

You are probably drawing too many amps from your power supply. I use a regular Sears battery charger, 12v 10amps. If you are using a power supply, I'm assuming you can change the voltage and amps, right? If you can. If you are using a small Pyrex bread dish, like most everyone does, you might want to try only a half lb of material at a time. When I try to do more than a half lb of pins, I run the risk of blowing the battery charger's fuse. The other reason you may be shorting out is that your Anode and Cathode are somehow touching. If you are not using a plain Pyrex dish, and the dish has a fine trace of metal like silver, or gold, for decoration, you might be shorting out on that if it touches both Anode and Cathode. Or you may have wires touching, or material bridging the gap between your Anode and Cathode. It might take some observation, but it can be fixed easily enough once you figure out the problem.

 

[Geo]

if you are using a converted ATI power supply, cut back on the amount of pins your are trying to run at one time. the older ones just cant hold that many amps for long.

 

[Axlrod2]

I don't even have close to a pound of material in the acid. Probably closer to sereval ounces. Is that to little? I am using a power supply from a computer putting out about 13 amps.

 

[Geo]

are you using the 12v or the 5v? a couple of ounces at a time is fine. the cathode has to be bigger than the anode. if you are using a wire mesh basket you will need a larger cathode. too the distance from anode to cathode causes resistance and makes the amps go up. you may be able to find a way to hang the basket closer to the cathode, a wire rod or wood rod to hang it on.

 

[Axlrod2]

Actually the more I thought I used the 2 amp wires. Tomorrow I'll use the 13 amp wires

 

[NobleMetalWorks]

That's probably why your power supply is shorting out, because the electrolytic process was trying to pull more amps than the power supply could give. I would wager that providing more amps for the process will fix your problem with the power supply shorting out.

 

[Axlrod2]

So now that I got my cell to work. After I filter the black surf from the acid, clean it of acid. Do I just boil it in muratic acid to "clean" it and then wash again. Then is it ready for testing and selling?

 

[Geo]

thats just the recovery part, now it needs to be refined. after rinsing with water, give the powder a good boil in hcl and follow with a boil in water.then dissolve the powder with which ever chemical you prefer.personally, id suggest hcl/Cl which is by far the easiest and fastest and then precipitate with SMB.

 

[Axlrod2]

I thought the dust was just gold. What else is there?

 

[Geo]

the sulfuric cell strips the gold, but as the sulfuric warms, it also strips some of the nickel, copper and dissolves a little bit of lead.it has a couple other traces of base metals that need to be cleaned up. if you take the powder with the little bit of acid and add it to 1,000 ml's of water and wait a few hours, the solution will turn green. you can remove a large part of the contamination this way by rinsing with water and waiting till the water stays clear. it still wont be contaminant free but it will be alot cleaner.

 

[NobleMetalWorks]

Assume that whatever precious metals you recover, have other metals present that you need to deal with. Remember also there are at least two parts to the overall process, there is recovering and refining. A stripping cell is used to recover, other types of cells can be used to refine. Anytime you recover, you are including other metals.

There are a few other things you can do to prevent as much other metals as possible, from being included in your "sand". You can watch you drop in amps/volts until it hits zero or close. That usually means you are finished de-plating. Also, you can put your cell in a bed of ice to keep it cool. Hot sulfuric acid is more likely to dissolve other metals than if it were room temperature.

Scott

 

[Geo]

scott, we try not to recommend someone use a bath where water can be introduced to the acid for safety reasons.if you do recommend something like that, please include the appropriated warnings about the dangers involved.

concentrated sulfuric acid will react violently when water is added and could cause steam explosions that will splash acid all over. WARNING : hot concentrated sulfuric acid will cause severe chemical burns on contact with exposed skin and cause blindness on contact with eyes. always wear safety equipment when working with sulfuric acid.

 

[NobleMetalWorks]

scott, we try not to recommend someone use a bath where water can be introduced to the acid for safety reasons.if you do recommend something like that, please include the appropriated warnings about the dangers involved.

concentrated sulfuric acid will react violently when water is added and could cause steam explosions that will splash acid all over. WARNING : hot concentrated sulfuric acid will cause severe chemical burns on contact with exposed skin and cause blindness on contact with eyes. always wear safety equipment when working with sulfuric acid.

You're right, thank you for correcting me Geo. To be crystal clear, the method I use is ice packs that are made of water, in poly bags, around the cell in a second Pyrex dish that is a little larger than the cell. I do it this way so that I do not have to use new ice each time, and also so that any Sulfuric acid does not accidentally come into contact with water. I use poly bags because they are resistant to acid.

Thank you for the correction, I'll make sure to post a safety warning along with any suggestions, and if this method is generally frowned upon, I won't suggest it again.

Scott

 

[nickvc]

Scott I think I speak for most of the active membership when I say you can post most processes so long as you point out any potential dangers or pitfalls that go with them. If you had stated that the ice bath was in the form of enclosed packs of ice and that was done to keep the water and sulphuric separate and the reason was that the mixing of the two was extremely dangerous then no problem.
I know it all seems a bit longwinded but the point to remember is we have members of all ages and levels of understanding and many whose first language isn't English so we try to make it as simple and with warnings when appropriate. I guess the point is we don't want anyone injured or worse and I'm sure you feel the same, we err on the side of caution to try to avoid accidents and if the poster misses the warnings someone else will usually step in to cover the point, feel free to do the same to any post by any member we really don't mind and it's not taken with offence.

 

[NobleMetalWorks]

Scott I think I speak for most of the active membership when I say you can post most processes so long as you point out any potential dangers or pitfalls that go with them. If you had stated that the ice bath was in the form of enclosed packs of ice and that was done to keep the water and sulphuric separate and the reason was that the mixing of the two was extremely dangerous then no problem.
I know it all seems a bit longwinded but the point to remember is we have members of all ages and levels of understanding and many whose first language isn't English so we try to make it as simple and with warnings when appropriate. I guess the point is we don't want anyone injured or worse and I'm sure you feel the same, we err on the side of caution to try to avoid accidents and if the poster misses the warnings someone else will usually step in to cover the point, feel free to do the same to any post by any member we really don't mind and it's not taken with offence.

:mrgreen: I have no problem at all being corrected, honestly, I, in fact, prefer to be corrected so I can be a more productive member of the forum, and as well, continue to learn as I have been. I run two forums myself that have nothing to do with the subject matter on this forum, and I understand all too well the dynamics of a forum, that is technical, such as this. I hope I didn't give anyone the impression that I am bothered by being corrected, because that is no where close to being the truth.

When I feel comfortable enough about what I know, and have enough experience under my belt, then maybe I can also contribute in the form of helping other people understand the correct way. Until then, I welcome being corrected so long as it has been as it has, insightful and with respect. I love to learn, and unlike some people I see being corrected as a lesson I might not have learned otherwise. I am fascinated with all of this, and spend most of my free time either reading and trying to contribute to this forum, or in my work. I have literally not slept more than 4 hours at a time, for months and months now. And I am absolutely having the time of my life. So please, if I say something that is not complete or not correct in some way, please, by all means, tell me. In the public forum is how I would prefer it so that others that read the thread will see the mistake I made, and learn from it as well.

:mrgreen:

Scott

 

[Axlrod2]

What kind of filter should I use?

 

[goldsilverpro]

What kind of filter should I use?

No filter paper will stand up to strong sulfuric.

 

[Axlrod2]

How do one filter out the sulfuric acid from the cell?

 

[Geo]

you decant the acid and powder into a glass container (i use a graduated cylinder) and let the powder settle.if it looks like its going to take a couple of days, i cover the top with a piece of clinge plastic wrap.the powder will settle to the point that the liquid becomes clear.decant this back into the cell and continue or store in a glass container with a screw on lid.the powder will still have a small amount of acid, just add this to about 1 quart of water very slowly until its all been mixed with the water.let the mixture settle. this will happen much more quickly (a couple of hours) and the solution will be green and acidic. carefully decant this to another glass container leaving the powder in the bottom.add water again and let settle, repeat this process until the water stays clear. the last rinse will leave you with clean powder with very little acid residue.