# Karat Cell experiments



## Noxx (Oct 18, 2007)

Hello everyone,
I just did a few tries with an home made karat cell.
Here is what I did:
Current: 1A MAX
Voltage: 7.5V
graphite cathode
10k gold anode
Aqueous solution: NaCl (regular table salt, ionised)

As soon as I started the current, bubbling started. But I notice a Chlorine smell so I stopped the experiment (30 sec total time lol, I'm inside)

Results: Blue coloration of the coffee filter, 10k gold turned black.

Pictures at the end...

Questions: 
I suppose the black powder on the ring is gold or silver chloride. But habitually, silver chloride is white lol. What could have cause the light blue colouration on the coffee filter ? I suspect copper ? And how could I stop the Cl gas emission ?
Lots of questions lol

Thanks


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## Noxx (Oct 18, 2007)

I just saw on the wiki, that the electrolysis of NaCl releases Chlorine gases...
Too bad... I have to find another electrolyte.


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## goldsilverpro (Oct 18, 2007)

I would guess that the black smut is gold. That's what the photo looks like. Metals tend to dissolve in an order similar to that in the electromotive series, from the top down, and I would think that the copper would tend to go before the gold. This would leave a gold sponge or, when thin, a black gold smut.

What do you want to accomplish with the cell? As the cell sits, you are plating as well as dissolving. The copper will plate out with the gold and you won't accomplish much, if anything, no matter what electrolyte you use. 

In one of the Shor patents, and maybe in the Simplicity cell, he uses ammonium chloride. This also dissolves the silver and prevents it from coating the anode. The Pt.Gp. metals end up as a sludge in the anode bag. It also uses a porous cup around the anode to create a separate anode compartment and a cathode compartment. If I remember right, the only things that pass through the porous cup are current and water molecules. The dissolved metals stay in the anode compartment and don't plate out. The gold is dropped out of the anode solution using SMB. 

I haven't used porous cups but I have used lots of similar membranes. In them, you could use completely different solutions in the anode and cathode compartments. It should be the same in the porous cup. In other words, you could use a chloride solution in the anode compartment and, say, a sulfate solution in the cathode compartment. This would prevent the evolution of chlorine at the cathode. You will still get hydrogen off the cathode, but that's easy to deal with.

Just thinking out loud.


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## lazersteve (Oct 18, 2007)

Noxx,

Before you give up on sodium chloride as the electrolyte try using a divided cell. I think it was scavenger that demonstrated the use of a crucible as the cell membrane of sorts as seen here:

Divided Salt Cell for Karat Jewelry

Be sure you read thru the whole topic as it has a lot of information on the salt cell. I am hoping to get back into my karat cell project using scavengers ideas as a starting point after I finish my PGMs DVD.

Steve


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## goldsilverpro (Oct 18, 2007)

Noxx.

Check this thread, also.

http://goldrefiningforum.com/phpBB3/viewtopic.php?t=485


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## Noxx (Oct 18, 2007)

Thanks for the link Steve,
but I don't understand why he doesn't get any Chlorine gases...

I have to buy a fusilica cup


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## Noxx (Oct 18, 2007)

Thanks, nice post too. I'm learning lol.


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## goldsilverpro (Oct 18, 2007)

If he used chlorides in the cathode compartment, he did get chlorine gas.


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## OMG (Nov 5, 2007)

If you used a membrane cell setup you should get chlorine gas at the anode, and sodium hydroxide and hydrogen gas at the cathode.
2NaCl + 2H20 -> Cl2 + H2 + 2NaOH 
If you used a single cell, you would get a mix of stuff because the NaOH can come in contact with the Cl being produced.


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## heirloomreplacement (Dec 21, 2007)

a little info for thought

I was running RGP with my cell the other night, and had quite a bit of gold in solution.
some of this scrap was over silver and I could see a silver sheen at times on the top of the solution.

So I got kind of curious as to what would happen if I set a 
(Corn Flake> as Harold calls them)
14 K down into the solution

I weighed it out first and found one that was at 1.9 g
the largest i had.

anyway My solution was quite hot at 285 deg from running the cell

as I watched > I had a lot of bubbles at both sides and the top coat around the cathadode turned brownish in color>

it ran up around 8 amps> so I left it in there for around 3-4 minutes to see what would happen.

after that I pulled it out> rinsed it a few times and weighed it again
it weighed 1.5G

Now knowing the Cell doesn't take up a lot of base metals I wonder what the loss was?
did it take gold into the solution ?
Silver? I don't think because i always see the silver around the Cathadode when i do gold over silver items and the color was brown which leads me to think gold was going into solution.

Anyone ever try to run KT gold into a pregnet De- Plating Cell before?

any thoughts?

and has anyone done any more work with the salt water devided KT Cell?

Thanks Jim


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## aflacglobal (Dec 21, 2007)

> My solution was quite hot at 285 deg from running the cell



:shock: :shock: :shock:


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## heirloomreplacement (Dec 21, 2007)

I see those Big looking eyes> lol

Yes I know it's Hot>

the firt time I did a large load of gold filled i hit almost 400 deg and had a fit when it started smoking.

I have never been able to find any actual temps from people running filled or RGP through a cell.

I know when i do the little gold plate i get it's much lower usualy around 140 deg or so.

But honestly I have been running filled and RGP throught this same cell for many batches without any issue> to date

I do let it cool down if it gets up to 300 deg
because it starts to smoke pretty good around 340 deg

always makes me to nervious to keep going.

keep in mind the scrap i process is usualy large items with heavy plating or filled > so I have become acustomed to seeing amps at 10 and temp at 200 plus

I use a doubble contained unit and a full scatter shield . and resperation
for Gas

Do you or anyone have any Temps I should get concerned about?

I cook sulfuric to make it stronger and it handles high temp without issue.
boiling point of sulfuric is way up there> 600 plus?

anyway it's been working for me
should i expect to blow up ?
should i secure my spark arrestor to the ground rod outside?

I'll take all the knowledge i can get
from all I read in the forum > i'm working in unchartered waters with this scrap and the process I use
I find very little about this type of refining

so bring it on> I'll listen :lol: 

Jim


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## lazersteve (Dec 21, 2007)

Jim,

Can you confirm the temperatures you are quoting are in Fairenheit or Celcius? I'm assuming F.

Concentrated sulfuric acid boils at 338 C.

Steve


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## heirloomreplacement (Dec 21, 2007)

Steve I was waiting > LOL

I do temps in F just out of habit> and i use an infered gun that is very accurate.


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## Noxx (Dec 21, 2007)

I taught it was in Celcius :lol: 


> I do let it cool down if it gets up to 300 deg
> because it starts to smoke pretty good around 340 deg


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## heirloomreplacement (Dec 21, 2007)

Sorry Guys

You must have guessed by Now I'm No chemist> lol

I talk and work in rude laymans terms> I should have been more accurate with my details.

Noxx> it starts smoking at around 340 F > and it gets to smell real bad if i take the make off> with the mask I can't smell anything :lol: 

I know concentrated Sulfuric boils at very high temp because I looked it the first time i hit 200 Deg F

I'm smart enough to know Battery acid and sparks do do well together

But other than sparks I don't see any real issue 

the only thing i have to pay special attention to is My clips>
with the hight amps I tend to get> if the clip gets near the solution it will be gone in minutes>
found that out the hard way> LOL

I will say the reg metal clips seem to last longer than stainless for me> which is totaly backwards of everything i have learned> but with the stainless clips the spring fails> i think because of high amps and so much heat>

I actually seem to get 2-3 times the life out of the plain steel ones i been using
they are a little bigger and have stronger springs.


My Lead cathadode has been the same one for over 50 hours on this cell> no sign of any wear.

( not 50 hrs. on same solution just same cathadode)

just trying to add info to what i have been finding 
JIM


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## lazersteve (Dec 21, 2007)

Jim,

I've never really measured the temperature of my cell while it's operational so I don't know what a 'normal' temperature is. I just place my gloved hand on the side of the cell to see if it's hot or not. 

My cell draws 8 amps typically while in operation and I run it for 2-3 three hours in a sitting. 

If your acid is known to be in the 98%+ range, when hot it can dissolve copper which is a likely ingredient in karated gold. 

The brown color at the cathode you mention is not uncommon when I run my cell with plated scrap. I'm not sure what it is , maybe GSP does.

When the cell is hot it will also dissolve silver into the electrolyte.

Excessive smoking is typically a sign of poor continuty at your connections. Check that your connecting leads are making good contact and are not sparking or acring. Usually the smoke will lead you to the arcing point.

Steve


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## heirloomreplacement (Dec 22, 2007)

Thanks For all the super feedback

Steve> yes I think you may be correct with the browish color i am seeing,

Note its not the same color I usually see when I strip yellow gold plate or filled.
It seems to be much lighter and come to think of it i had a redish brown film covering the KT gold flake when I pulled it out.

So I think you are right on with copper being the metal going into solution.

I should start a new post on the differant colors I see when I strip RGP and Filled scrap> lol
As this post was more toward KT Cells experiments.

Besides the normal colors I see at the top of the cathdode

Normal 
1) dark brown or Black > Gold

2) dark Redish > copper

3) bright silver > silver?

4) Light gun metal Blue ?? > i have no clue , but i get it on pre. 1940's
white gold filled, RGP 
rarely with 14K > 
almost always I get this color with 18 -19-20 K RG

I just asume it's alloyed to make white gold> possable PT group?

again Just to be clear> 75% of the scrap I deal with is KT filled or RG from early 1920's to 1950's

JIM


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