Muradic acid w/Carbon electrodes Hydrogen/Chlorine process

Hello all,
Forgive me if this process has been discussed previously. I did a search on the topic but didn't see anything posted.

For the past 6 months I have been using Muradic Acid as an electrolyte in a vertical column with carbon rods/disks as electrodes, Cathode at the bottom and anode at the top, to disolve gold and other metals from boards and fingers.

I use 8-15volts DC and around 10amps to disolve everything including platinum into the solution. The platinum disolves when the solution is heated (I just turn up the juice and that is sufficient to increase the temperature. It will boil if you let it.
Using higher amps, dissolve everything faster, but be aware of the hydrogen bubbles that will vented out the top of your column. Make sure the connections to your top electrode are secure and don't remove it while the power is on or you can create a spark resulting in possible BANG!

As the metals begin to dissolve, copper will plate to the anode (top carbon rod or disk). I periodically turn off the power, remove the electrode and scrape the copper off into a separate container.

The solution turns green at first, then a much darker color at the bottom, as Hydrogen/Chlorine is created and slowly moves up the column. The solution is contained and never escapes the rig (unless you have a spill) Very interesting to watch it attack the boards. The gold falls off and sometimes create a bright pure gold ring around the column.

The time to complete the process will vary with size of your column and amount of current applyed. Mine is a cylinder glass flower vase I found at Marshals ($10), and is about 2.5' x 7" 1/4" thick. It usually completes the process in 2 days. You can use a plastic bucket, 5 gallon water jug, or tupperware container from wallmart if you want.

But the fun begins when you try to connect the bottom electrode to the power lead without allowing it to come in contact with the solution.
I use a volt and amp meter connected to the rig so I can tell if a connection is compromised.

I also use Dow Corning 3140 RTV to coat all contacts points, with the lead running through a small hole I drilled in the side of the glass. (took about 30min to slowly drill with a glass bit) I filled the bottom of the container with the sealent up past this hole (about 1" thick) I encased the carbon disk and its connection in the sealant allowing only the top side of the electrode to be visible.

You can try running a wire down the inside of the column but will run into problems as the solution slowly penetrates the wire. I even tried using coated wire used in the oil and gas industry but found the next weakest link was the connection.

Using glass I find the RTV sufficient even when the glass flexes due to temperature change. Plastic containers dont seem to hold as well. If you do use plastic make sure to put the whole thing in a container (5 gallon bucket) just in case you spring a leak.

The advantage to this process is only needing Muradic, and not having to deal with Nitric.

Plus no need for urea, just SMB out the gold.

A word of advise, make sure you do this process in a place where you can vent off the fumes. I learned that lesson when I discovered everything in my kitchen (where I had the rig running) started to corode.

I can post photos of my rig if you are interested.

Your comments please.

Thanks
DallasGoldBug

Clever setup. I can see how generating Chlorine gas at the bottom of the column would aid digestion by circulating the liquid.

Once the solution is saturated with Chlorine, generating more will just create excess pressure and outgassing of the Chlorine.

Have you tried to cycle the power to generate the Chlorine as needed?

dallasgoldbug please do post pictures of your setup, what a marvelous way to manufacture chlorine for digestion.

Irons I think you hit it when you suggested pulsating the current as needed. I think this rig has a lot of potential and plenty of room for modifications.

Gill

Ive been researching patents and processes while I design a stand alone unit. The liquid would circulate through a second column where it can be cooled or heated along with filtered, then running through a condenser enabling the acid to be reused.

Only having to deal with only Muradic cuts production costs and recycling/reusing it eliminates having to dealing with disposal of harmful by products.

So far I haven't had a problem with out gassing. Seems to remain contained in the liquid. I typically run it without a lid to allow the hydrogen to escape. In the final design the reaction chamber will be enclosed, but until I get it finished, Ive been building an active charcoal filter attachment that eliminates most of the corrosive fumes.

The goal is to have a small closet size unit that can constantly run. All you would have to do is keep throwing in the fingers/scrap and switching out the end filters containg your end product.
Another option is to plate the end product out.

Make sure you throw me a bone if you uses my ideas to make a billion.
Donations are happily accepted.

What if you used the first column to generate the chlorine, introducing the gas into the base of a second column containing your gold bearing scrap.

Wondering if you could run the second column dry with only the chlorine passing through. After a couple of days introduce a water bath to dislodge any values, drain and collect for further preperations.

The advantage of the seconded column would be that you would not have to clean your carbons nor filter the muriatic acid.

Gill

Yep using a second column to generate it was a thought, but keeping the carbon electrodes in the loop has its advantages. It removes the copper (as mentioned before) but by changing the carbon to other materials is a way to to plate out other metals plus the bubbles that travel up the column also assist in removing the gold.

You'll find yourself with flashlight in hand fixated for hours watching the process. I finally ended up running a plexiglass rod down the inside wall and attached the end to 4 LEDs. It works well to illuminate the solution.

Additionally using the electrodes heats the solution making it work much faster this allows platinum to be dissolved without adding external heat. Of course you could heat the second column to achieve the same effect, but this just consumes more power, introduces additional hardware, and creates additional opportunity for accidents to happen. That was a bad day :shock: almost bit the big one when the column took a fall.

I just took some photos of the setup and will post them in a few minutes.

Photo:
#2 Looking down the column at the carbon disk at bottom imbeded in RTV

#3 Top Electrode attached to pvc holder with RTV surrounding it. the electrode is attached to a stainless rod that can be lowered down into the column so the electrode touches the liquid. The blue cap is a plastic bottle cap acting as a nut that the electrode is lowered through.

#4 top of the stainless rod. Stainless wire connection that goes to neg of power. As long as there is a current running through the stainless it will resist corrosion. You could use a stainless container for the reaction vessel but if the power were to go out, the solution would begin to eat it. So stick to plastic or better glass.

#5 rig is in the center. TO the left is a HHO column that I built to generate Hydrogen for welding and cutting. Soon to be installed in my car.

#6 Bottom of column showing the hole drilled in it connecting the anode to the positive power.

#7 Small DC Power supply with two multimeters to read volts and amps while your cooking. Also shows if there is an open in your setup.

#8 Base of the column (an old subwoofer speaker. I mounted a computer fan in the center that can be used in emergencies to cool the column.

#9 rig with top on

#10 Old unit I built with two gravity filters attached to the side that filtered the solution as it cycled.

#11 Small cups that stack together. each with drain holes in bottems. (bought them at dollar store) They screw together and can stack as many as you want. Helpful when removing the fingers after processing or retrieving gem stones from jewelry.

#12 me and the rigs

photos 2

You may find that this unit, basically a HCl/Cl digester, may work just as well at room temperature since the solubility of CL2 in water decreases rapidly as the temperature rises. The chlorine is what does the digestion and even though increasing the temperature will speed up the reaction, it will slow down because of loss of Chlorine.
You might also try diluting the HCl since the process works very well in a Ph range of 1-5. This will save on having to distill of or neutralize excess HCl and reduce loss from evaporation. Using NaCl /HCl as a Chlorine source is another tack to consider.

I have material digesting nicely in the barn at 0 Deg. C using HCl/Cl and even on a day that went down to -23 Deg. C, it was still digesting away nicely because the Chlorine concentration can get quite high at those temperatures without outgassing.

Dallas,

Neat rig.

Some questions:

How much scrap do you process in a single 2 day cycle?

What other metals end up in the solution and which end up as a sludge in the bottom?

How does silver react in the chamber?

How often do you have to scrape the copper off the cathode ?

Any issues with anode or cathode decay ?


Some safety notes:

1) I'd be concerned about the glass vase shattering if the temperature where to change too rapidly.

2) You should support the cylinder better, it looks fairly easy to topple while sitting on top of the speaker cone.

3) A hose routing the H2 gas outside should be added to protect against accidents during extend operation.

and some comments:

The gold produced would most likely require a second refining.

The liquid around the copper sludge may contain dissolved gold, so the sludge should be rinsed well with water.

The unit would need to be completely disassembled periodically to clean all the build up from the inside.

This is a very good idea Dallas.

Steve

Where did you get a carbon disc like that. I've been working on some electrolysis cells myself. The best thing so far I've found is carbon rods used for gouging (welding supplies). But they degrade. Do you have problems with the carbon degrading too?
Have you considered using a titanium plated disc as your anode?

Wow that looks great.

Wondering if the hydrogen and excess clorine recombine in the gas phase at the top of the unit and go back into solution? they react in light if I remember correctly.

Edit - I want one -

Platinum huh.......ok, throw some cat material in it and see what happens..
........
Randy

Randy,

I tried a honeycomb in HCl-Cl this past weekend and successfully extracted a very small amount of Pt, the strange thing was there was no Pd in the solution, only Pt.

Steve

Gotcha.......

what voltage are you running at?

James, he stated this...."I use 8-15volts DC and around 10amps to disolve everything including platinum into the solution. "

Interesting.


Knowing the amount of electricity going into it, you can determine exactly how much platinum, gold, or whatever you are oxidizing.

Coloumbmetry.

Oh, thanks, missed that. Been working since 4AM today.

Jim

Lazersteve, Thanks for the tips. By the way love your site. Its an excellent source of info. Your a wealth of information, thanks for sharing it with us.

I have some additional harvesting techniques Ill post in the appropriate category. Ill try to video them as well and post them to youtube.

To answer your questions:

Q: How much scrap do you process in a single 2 day cycle?
A: That column, if finger are placed neatly can hold 5-8lbs. But Ive made reactors for friends out of plastic 5gallon water bottles (5gallon buckets are easy to use but you cant monitor the reaction as well. Watching it ,through the side of the column is much more enjoyable.

For the water bottles I cut a small hole close to the top enabling easier access to place the disks and your scrap in the jug. Cutting off the top weakens the integrity of the bottle. Ive been trying to bribe the manager of my local home depot to sell me the blue water bottle racks they have in the store. They hold multiple jugs securely which would be perfect to build a wall of reactors in a closet or garage for large scale production.

In the bottom of the buckets or jugs I place 6 disks (5 surrounding 1 in the center) on a flat piece of copper. Then fill the jug up to the top edge of the disks with RTV. After thats cures, I then drill the hole through the side, (or bottom depending on how they will be using the jug) into one of the disks, for the connection. In the bottom configuration i secure a bolt so the head will make contact when the bottle is placed on a metal rack or plate. By connecting your positive to a plate or metal stand neatens it up a bit, and makes it easier to move the jugs.

Q: What other metals end up in the solution and which end up as a sludge in the bottom?
A: I try to trim my fingers neatly, and wash the final scrap, removing dirt, finger grease and loose particles. I also have some harvesting techniques that ill share later that remove almost all the solder from boards.

So far I haven't had any metal sludge at the bottom it dissolves everything, finger come out nice and clean. I focus mainly on gold and my scrap is usually gold/coper plated. Like I said platinum is dissolved when the temp is increased. But I rarely process anything other than gold. As for any other metals I cant say, but judging on how it eats the platinum, I would guess other metals would be similar.


Q: How does silver react in the chamber?
A: It gets dissolved as well.

Q: How often do you have to scrape the copper off the cathode ?


A: I usually scrape the anode 2-3 times a day. The cathode doesn't get anything on it since the current flow from positive to negative. I like to keep an eye on it because, as you mentioned some gold will make its way in with the copper. For this reason the copper scrapings are collected and processed with hcl/peroxide method(as seen on your website)

The copper grows like a fuzzy tree off the electrode. You have to VERY SLOWLY lift the electrode or it will fall back in. For this reason I hang one of those plastic cups with small holes in the bottom of it, under the electrode to catch the falling bits.

Tip: Be careful not to score the surface of the electrode. keeping it smooth you'll find the copper peals off easily. If there are grooves or scratches the copper has more of a foothold.

You can distinguish the gold from the copper easily due to its color. But processing it will ensure you get all of it.


Q: Any issues with anode or cathode decay ?


A: Surprisingly, so far there has been very little decay. I estimate running the rig 40 times in the past 6 months and have no noticeable loss. I get the disks for about $10 each. I can get larger disks up to 12" dia and cut to whatever thickness I request. The disk size in the photos are a good size to work with when I build rigs for others.

Q: Have you considered using a titanium plated disc as your anode?

A: Yes but would really hate to come home one day to find them dissolved due to loss of power, blown fuse, or power supply failure.

Like I mentioned you should use stainless as well as long as there is current passing through it, it will not be dissolved.

Using a stainless reaction vessel is not a good idea. In addition to the above mentioned problem, the reaction is designed to take place between the electrodes. Since the anode is partially submerged and sealed around the edges to the pvc cap (as seen th the photo) keeps the reaction contained under the liquid. If you just stick the anode into the solution you will be creating a reaction on the surface as well as in the column. As I mentioned, in the beginning I found this out the hard way after everything metal in my kitchen corroded. Plus it was a pain loosing connection due to the fumes were dissolving the wire contact to the anode. Sealing it up as seen in the photo eliminates the problems. Your lungs will thank you later.
:wink:

Sorry for the long post. Hope I answered all the questions.