Critique / discuss electrolytic methods

[aussie_noob]

I have multiple methods prepared, please critique these and give tips. Using quality materials, done university chemistry.

Method 1. No acid electrolytic stripping of base copper with electrical contact

Example video

### Materials and Equipment:
- 250 grams of copper sulfate
- 1 liter of distilled water
- Gold-plated copper substrate (anode)
- Stainless steel electrode (cathode)
- Adjustable power supply

### Process:
1. **Prepare Solution**: Dissolve copper sulfate in distilled water.
2. **Setup Electrodes**: Attach the gold-plated copper to the anode and the stainless steel to the cathode.
3. **Voltage Application**: Apply 2.0 to 3.0 volts.
4. **Electrolysis**: Copper dissolves, leaving gold behind.
5. **Collection**: Turn off power, decant or filter to collect the gold.

Q. Will gold flakes with attached copper fall off and not be pure gold, requiring further refining?
Q. Gold losses? Where, how, how to prevent?

Method 2. Sulfuric acid reverse electroplating

Example video

### Materials and Equipment:
- 98% Sulfuric acid (H2SO4)
- Lead electrode (cathode)
- Gold-plated material (anode)
- Adjustable power supply
- Filter paper and filtration setup
- Aqua regia (HCl and HNO3 mixture)
- Distilled water
- Glass container

### Process:
1. **Prepare Bath**: Fill the glass container with sulfuric acid.
2. **Setup Electrodes**: Connect gold-plated material to anode and lead electrode to cathode.
3. **Apply Voltage**: Use the power supply to achieve about 1 amp of current. Gold strips from the anode and precipitates.
4. **Filter**: Collect precipitate by filtering the solution.
5. **Burn**: Burn the filter paper to obtain ash containing gold.
6. **Dissolve in Aqua Regia**: Mix the ash with aqua regia to dissolve gold.
7. **Extract Gold**: Filter aqua regia solution and precipitate gold using sodium metabisulfite (SMB).


Method 3. Ai generated method: Non-electrical contact reverse electroplating (I want a real method similar to this fake method)


### Materials and Equipment:
- Hydrochloric acid (HCl)
- Hydrogen peroxide (H2O2)
- Stainless steel electrodes (anode and cathode)
- Gold-plated copper substrate
- Adjustable power supply
- Glass container
- Distilled water

### Process:
1. **Prepare Solution**: Mix three parts HCl with one part H2O2.
2. **Setup Electrodes**: Place stainless steel electrodes in the solution. The gold-plated copper substrate should not touch the electrodes directly.
3. **Voltage Application**: Apply 1.5 to 3.0 volts.
4. **Electrolysis**: Gold dissolves and migrates to the stainless steel cathode.
5. **Collection**: Turn off power, remove and recover gold from the cathode.

Please tell me something like this exists? I don't want to electrically contact all my samples.

 

[Yggdrasil]

I have multiple methods prepared, please critique these and give tips. Using quality materials, done university chemistry.

Method 1. No acid electrolytic stripping of base copper with electrical contact

Example video

### Materials and Equipment:
- 250 grams of copper sulfate
- 1 liter of distilled water
- Gold-plated copper substrate (anode)
- Stainless steel electrode (cathode)
- Adjustable power supply

### Process:
1. **Prepare Solution**: Dissolve copper sulfate in distilled water.
2. **Setup Electrodes**: Attach the gold-plated copper to the anode and the stainless steel to the cathode.
3. **Voltage Application**: Apply 2.0 to 3.0 volts.
4. **Electrolysis**: Copper dissolves, leaving gold behind.
5. **Collection**: Turn off power, decant or filter to collect the gold.

Q. Will gold flakes with attached copper fall off and not be pure gold, requiring further refining?
Q. Gold losses? Where, how, how to prevent?

This will be more or less straight forward but will be equivalent with dissolving the Copper directly in either Nitric or Cupric Chloride.

Method 2. Sulfuric acid reverse electroplating

Example video

### Materials and Equipment:
- 98% Sulfuric acid (H2SO4)
- Lead electrode (cathode)
- Gold-plated material (anode)
- Adjustable power supply
- Filter paper and filtration setup
- Aqua regia (HCl and HNO3 mixture)
- Distilled water
- Glass container

### Process:
1. **Prepare Bath**: Fill the glass container with sulfuric acid.
2. **Setup Electrodes**: Connect gold-plated material to anode and lead electrode to cathode.
3. **Apply Voltage**: Use the power supply to achieve about 1 amp of current. Gold strips from the anode and precipitates.
4. **Filter**: Collect precipitate by filtering the solution.
5. **Burn**: Burn the filter paper to obtain ash containing gold.
6. **Dissolve in Aqua Regia**: Mix the ash with aqua regia to dissolve gold.
7. **Extract Gold**: Filter aqua regia solution and precipitate gold using sodium metabisulfite (SMB).

This is often done in an basket of Copper mesh.
The Sulfuric will dissolve any paper so it is better to give it time to settle and decant the majority of the acid and then dilute the acid and decant again.
It is not necessary to use AR for this, better use HCl/Peroxide or HCl/Chlorine.

Method 3. Ai generated method: Non-electrical contact reverse electroplating (I want a real method similar to this fake method)


### Materials and Equipment:
- Hydrochloric acid (HCl)
- Hydrogen peroxide (H2O2)
- Stainless steel electrodes (anode and cathode)
- Gold-plated copper substrate
- Adjustable power supply
- Glass container
- Distilled water

### Process:
1. **Prepare Solution**: Mix three parts HCl with one part H2O2.
2. **Setup Electrodes**: Place stainless steel electrodes in the solution. The gold-plated copper substrate should not touch the electrodes directly.
3. **Voltage Application**: Apply 1.5 to 3.0 volts.
4. **Electrolysis**: Gold dissolves and migrates to the stainless steel cathode.
5. **Collection**: Turn off power, remove and recover gold from the cathode.

Will not work due to the lack of contact, the only effect will be that the HCl will be split up and create some free Chlorine.
Stainless steel do not handle HCl well.
HCl Peroxide will dissolve all metals in solution by itself given some time.


Please tell me something like this exists? I don't want to electrically contact all my samples.

For ease I will comment in bold inside the reply quote.

You will be better off with a selective leach for Gold.

 

[aussie_noob]

For ease I will comment in bold inside the reply quote.

You will be better off with a selective leach for Gold.

Thanks for the replies to each part, quite insightful. Cyanide would be amazing! Wish I could get it. I'll look into thiosulphate as an alternative. Yeah, cyanide would be really great.....

Oh, didn't think of using a basket for method 2. Hmmm i'll drill some holes in my anode containers for drainage.

For method 3. Does this mean there's no way to put electrodes in some chemical bath, dip non electrically contacting gold plated stuff in and have the gold selectively migrate to the cathode? I feel like this should be possible somehow? Maybe not, chemicals that dissolve the gold would also attack the cathode gold plating.... yeah fair enough.

EDIT: ahhh, selective leach and simultaneous electrowinning. This is getting fun.

 

[Yggdrasil]

Thanks for the replies to each part, quite insightful. Cyanide would be amazing! Wish I could get it. I'll look into thiosulphate as an alternative. Yeah, cyanide would be really great.....

Oh, didn't think of using a basket for method 2. Hmmm i'll drill some holes in my anode containers for drainage.

For method 3. Does this mean there's no way to put electrodes in some chemical bath, dip non electrically contacting gold plated stuff in and have the gold selectively migrate to the cathode? I feel like this should be possible somehow? Maybe not, chemicals that dissolve the gold would also attack the cathode gold plating.... yeah fair enough.

EDIT: ahhh, selective leach and simultaneous electrowinning. This is getting fun.

The electrode basket is usually made of copper mesh.

 

[4metals]

In the first scenario the process may benefit from bagging the anode to collect what drops off, in a beaker this may be a moot point but in a larger tank with bigger anodes and cathodes the anodes will be better off bagged.
As far as purity it will be no more or less pure than collecting foils from the AP process.

 

[Yggdrasil]

Thanks for the replies to each part, quite insightful. Cyanide would be amazing! Wish I could get it. I'll look into thiosulphate as an alternative. Yeah, cyanide would be really great.....

Oh, didn't think of using a basket for method 2. Hmmm i'll drill some holes in my anode containers for drainage.

For method 3. Does this mean there's no way to put electrodes in some chemical bath, dip non electrically contacting gold plated stuff in and have the gold selectively migrate to the cathode? I feel like this should be possible somehow? Maybe not, chemicals that dissolve the gold would also attack the cathode gold plating.... yeah fair enough.

EDIT: ahhh, selective leach and simultaneous electrowinning. This is getting fun.

What happens when you attach the metal to one of the electrodes and push a voltage onto it is that you create either a surplus or deficit of electrons (charges it).
This in turn creates the basis for the situation/process we want to have.
If it is not connected, it will just sit in the same liquid without any charge.

 

[aussie_noob]

What happens when you attach the metal to one of the electrodes and push a voltage onto it is that you create either a surplus or deficit of electrons (charges it).
This in turn creates the basis for the situation/process we want to have.
If it is not connected, it will just sit in the same liquid without any charge.

Thanks 4metals for the bagging idea for large quantities. I'm going back to the drawing board. I suspect that cyanide/thiolsulphate leaching and simultaneous electrowinning could work? The leach converts the solid gold to ionic gold that can then migrate to negative cathode. Sure you don't have a positive charged gold anode pushing gold into solution, but you still got the negative pulling. Slower process, but should work? Possible i'm just an idiot. I'll try and prove it works if any aussies will lend me some leach.

 

[Yggdrasil]

Thanks 4metals for the bagging idea for large quantities. I'm going back to the drawing board. I suspect that cyanide/thiolsulphate leaching and simultaneous electrowinning could work? The leach converts the solid gold to ionic gold that can then migrate to negative cathode. Sure you don't have a positive charged gold anode pushing gold into solution, but you still got the negative pulling. Slower process, but should work? Possible i'm just an idiot. I'll try and prove it works if any aussies will lend me some leach.

Electrowinning is usually done with electrodes quote close to each others and pumping the leach either between or through the electrodes as in carbon felt or steel-wool.
Not very practical in a leach tank, so it usually are a unit outside the tank.

 

[aussie_noob]

Electrowinning is usually done with electrodes quote close to each others and pumping the leach either between or through the electrodes as in carbon felt or steel-wool.
Not very practical in a leach tank, so it usually are a unit outside the tank.

Ahhh, these are the smart things I like to hear! Never thought of that. So bonded leach-gold is net neutral charge and doesn't get electrically pulled to cathode in electrowinning, it's just diffusion. We need convection for far separated electrodes.

Method 4: Simultaneous Leaching, Electrowinning and Convection (EDIT: UNSAFE, NOBODY TRY THIS. Need alkaline solution)

### Materials and Equipment:
- Sodium cyanide solution (0.1-0.5%)
- Stainless steel electrodes (anode and cathode)
- Gold-plated objects (non-electrically connected)
- Adjustable power supply
- Glass or plastic container
- Distilled water
- Magnetic stirrer with inert stir bar

### Process:
1. **Prepare Solution**: Dissolve sodium cyanide in distilled water to make a 0.1-0.5% solution.
2. **Setup Electrodes**: Place stainless steel electrodes in the solution.
3. **Apply Voltage**: Connect electrodes to a power supply and apply 2.5 to 3.5 volts.
4. **Initiate Convection**: Place the container on a magnetic stirrer, insert the inert stir bar, and turn on the stirrer to ensure constant convection.
5. **Add Gold-Plated Objects**: Carefully immerse the gold-plated objects in the solution without touching the electrodes.
6. **Electrolysis and Leaching**: The gold-plated objects leach, gold ions dissolve, and migrate to the cathode, depositing as solid gold.
7. **Collection**: Once sufficient gold has deposited on the cathode, turn off the power, remove the cathode, and recover the gold.

So basically, put non-electrically connected gold plated stuff in bath, wait, then pull gold off cathode. Repeat.

Will this not work?

 

[Yggdrasil]

Ahhh, these are the smart things I like to hear! Never thought of that. So bonded leach-gold is net neutral charge and doesn't get electrically pulled to cathode in electrowinning, it's just diffusion. We need convection for far separated electrodes.

Method 4: Simultaneous Leaching, Electrowinning and Convection

### Materials and Equipment:
- Sodium cyanide solution (0.1-0.5%)
- Stainless steel electrodes (anode and cathode)
- Gold-plated objects (non-electrically connected)
- Adjustable power supply
- Glass or plastic container
- Distilled water
- Magnetic stirrer with inert stir bar

### Process:
1. **Prepare Solution**: Dissolve sodium cyanide in distilled water to make a 0.1-0.5% solution.
2. **Setup Electrodes**: Place stainless steel electrodes in the solution, ensuring the gold-plated objects are immersed but not touching the electrodes.
3. **Apply Voltage**: Connect electrodes to a power supply and apply 2.5 to 3.5 volts.
4. **Initiate Convection**: Place the container on a magnetic stirrer, insert the inert stir bar, and turn on the stirrer to ensure constant convection.
5. **Electrolysis and Leaching**: The gold-plated objects leach, gold ions dissolve, and migrate to the cathode, depositing as solid gold.
6. **Collection**: Get gold off cathode.

Gold in Cyanide or other solution are not neutral as they are in an ionic state.
For example as a positive Gold complex and negative CN^-.
But they are not very mobile and will just follow the liquid until.they come close enough to the cathode to aquire an electron and become Au(0).
That is why an electrowinning cell are usually in a pumping circuit so you can pump the pregnant solution through it.
It will not be completely barren though, some Gold will stay back so after the Leaching is done it is usually put through a cementation cycle to get out the remaining values.

 

[aussie_noob]

Alright, gotta extract remaining gold in solution at the end. Also adding safety steps.

NOTE: Nobody try this, hazardous chemicals.
Method 4 (revised): Simultaneous Leaching, Electrowinning, and Convection with Multiple Runs and Cementation Cycle

### Materials and Equipment:
- Sodium cyanide and NaOH alkaline solution (pH 10-11)
- pH test strips
- Stainless steel electrodes (anode and cathode)
- Gold-plated objects (non-electrically connected)
- Adjustable power supply
- Glass container
- Distilled water
- Magnetic stirrer with inert stir bar
- Cementation agent (e.g., zinc powder)
- Filter paper

### Process:
1. **Setup Electrodes and Stirrer**: Place electrodes in the container at 2.5 to 3.5 volts and add stirrer.
2. **Add Alkaline Sodium Cyanide Solution**: Prepare the solution with a pH of 10-11 and add it to the container.
3. **Add Gold-Plated Objects**: Immerse the gold-plated objects in the solution without touching the electrodes.
4. **Electrolysis and Leaching**: The gold-plated objects leach, gold ions dissolve, and migrate to the cathode, depositing as solid gold.
5. **Regularly Check pH**: Regularly check pH, and maintain at 10 to 11.
6. **Remove and Add New Objects**: When gold-plated objects lose gold, take them out of the solution and add new gold-plated objects.
7. **Repeat Process**: Continue steps 4 to 6 for multiple runs.
8. **Collection**: Turn off the power, remove the cathode, and peel off the deposited gold.
9. **Cementation Cycle**: Add a cementation agent to the solution. The remaining dissolved gold will precipitate out and can be collected by filtration.

DO NOT TRY ABOVE PROCEDURE! CHEMICAL HAZARDS! use safer alternative methods.

Imagine this: get a container, put electrodes on sides, add stirer and chemical solution, then just dunk in baskets of gold plated stuff one at a time, you've got refined high purity gold. DONE. Pour the chemical bath into a container and do cementation another day to get the remaining bit of gold. Shame the chemicals are difficult to handle safely.