AP on my way

[VolkD]

The liquid is also clear but blue.

 

[4metals]

That seems like you used a lot of persulfate in the solution for that quantity of crystallization, or was that after you decanted a lot of liquid?

 

[VolkD]

It's really cold outside at night, temperatures can go down to -8°C. Because I didn't want my glass to crack because of the ice, I warmed it up a bit. I didn't even think about the water evaporating.

 

[dwtmint]

I have been researching persulfates as a fast gold finger releasing solution, to keep halides as far away from the gold as possible. Then I searched persulfates here and found this thread. I'll share some of what I've found:

1. There are apparently many ways to "activate" persulfates in solution (which are basically salts of piranha solution). What is meant by activation is the generation of sulfate radicals, which have an oxidation potential around that of Florine. Some common ways to activate persulfates are heat (50c-70c), UV light, base metal ions (Fe and Cu in particular), silver ions and alkalinity to name a few.
2. Attached are papers from 2016 and 2017 where ammonium persulfate was was explored as a way to recover gold from ewaste by removing the substrate. They were able to get 100% gold release in 5 minutes with 30psi pressure (pressure cooker) or 40 minutes with heat (70c I think) at normal pressure. Spent Ammonium Persulfate is Ammonium Sulfate.
3. Ammonium Persulfate (aka APS) can be regenerated or generated by electrolyzing a saturated ammonium sulfate solution with 30% by weight sulfuric acid. In theory you might could have a gold finger removing solution that was constantly electrolyzed regenerating the APS, you would have base metal sulfates in solution.
4. Potassium Peroxymonosulfate (PMS) is the potassium salt and sold in the pool section as non-chlorine shock. I bought some to experiment with, though I think I will likely go the APS route from electrolyzing ammonium sulfate (cheap fertilizer).
5. Most persulfate research can be found around the buzz term PS-AOP or PerSulfate based Advanced Oxidation Processes, which mainly refer to the use of persulfates to oxidize organic pollutants to CO2 from sewage to underground. The uses are not limited to organic pollutants.

There is much more than I can write here now, but long story short, I think it is definitely a promising alternative to CuCl and other halide based methods to release gold and possibly even dissolve base metals from inquarted gold.

 

[Martijn]

I have been researching persulfates as a fast gold finger releasing solution, to keep halides as far away from the gold as possible. Then I searched persulfates here and found this thread. I'll share some of what I've found:

1. There are apparently many ways to "activate" persulfates in solution (which are basically salts of piranha solution). What is meant by activation is the generation of sulfate radicals, which have an oxidation potential around that of Florine. Some common ways to activate persulfates are heat (50c-70c), UV light, base metal ions (Fe and Cu in particular), silver ions and alkalinity to name a few.
2. Attached are papers from 2016 and 2017 where ammonium persulfate was was explored as a way to recover gold from ewaste by removing the substrate. They were able to get 100% gold release in 5 minutes with 30psi pressure (pressure cooker) or 40 minutes with heat (70c I think) at normal pressure. Spent Ammonium Persulfate is Ammonium Sulfate.
3. Ammonium Persulfate (aka APS) can be regenerated or generated by electrolyzing a saturated ammonium sulfate solution with 30% by weight sulfuric acid. In theory you might could have a gold finger removing solution that was constantly electrolyzed regenerating the APS, you would have base metal sulfates in solution.
4. Potassium Peroxymonosulfate (PMS) is the potassium salt and sold in the pool section as non-chlorine shock. I bought some to experiment with, though I think I will likely go the APS route from electrolyzing ammonium sulfate (cheap fertilizer).
5. Most persulfate research can be found around the buzz term PS-AOP or PerSulfate based Advanced Oxidation Processes, which mainly refer to the use of persulfates to oxidize organic pollutants to CO2 from sewage to underground. The uses are not limited to organic pollutants.

There is much more than I can write here now, but long story short, I think it is definitely a promising alternative to CuCl and other halide based methods to release gold and possibly even dissolve base metals from inquarted gold.

The electrolisys method is not suitable for stripping foils from pcb's as the persulfate only exists close to the anode if i understood it correctly.

regarding inquarted gold: Not including white gold, and I still have to run some tests with 'high' silver content gold, but the sulfuric cell 'dissolves' or actually parts karat gold.

No need to inquart and find an alternative for nitric to eat 3 times as much as the gold you have to refine.

You can just part the alloy in the cell and, in comparison to inquarting, dissolve the tiny amount of silver present in the slimes with way less nitric or simply in your AR digestion or leave it in the slimes as you dissolve the gold out with HCl & bleech, completely leaving nitric out of the process.

 

[ólom]

Yesterday I made an AP with a little hydrogen peroxide and bubbled it. Do you think I could add sodium persulfate? I'm asking about the hydrogen peroxide.

 

[VolkD]

Yesterday I made an AP with a little hydrogen peroxide and bubbled it. Do you think I could add sodium persulfate? I'm asking about the hydrogen peroxide.

Hydrogen peroxide + hydrochloric acid will also be golden in principle. Not a good combination.

 

[ólom]

Hydrogen peroxide + hydrochloric acid will also be golden in principle. Not a good combination.

Thank you!

 

[VolkD]

I did a new experiment. This time I threw printed circuit boards full of solder into the solution. I didn't bother to remove it.
I put 0.8l of hydrochloric acid, 0.2l of copper chloride from the previous batch and 45g of sodium persulfate in a beaker. I heated it to about 60°C. I also added bubbling air bubbles.
I added sodium persulfate three times. 15g+15g+15g. At the beginning, after 12 hours and after 24 hours.
At the beginning I added 0.6l of hydrochloric acid, and after 24 hours I added 0.2l.
The whole process took 36 hours, but I think it would be good to wait at least another 6 hours.
I am currently working on filtering. I will probably add another 0.2l of hydrochloric acid, as the liquid is thick and dark brown (saturation). This is causing the filter to clog.

 

[Martijn]

I did a new experiment. This time I threw printed circuit boards full of solder into the solution. I didn't bother to remove it.
I put 0.8l of hydrochloric acid, 0.2l of copper chloride from the previous batch and 45g of sodium persulfate in a beaker. I heated it to about 60°C. I also added bubbling air bubbles.
I added sodium persulfate three times. 15g+15g+15g. At the beginning, after 12 hours and after 24 hours.
At the beginning I added 0.6l of hydrochloric acid, and after 24 hours I added 0.2l.
The whole process took 36 hours, but I think it would be good to wait at least another 6 hours.
I am currently working on filtering. I will probably add another 0.2l of hydrochloric acid, as the liquid is thick and dark brown (saturation). This is causing the filter to clog.

I advise to keep track of the amount and costs of your acids, time spent to process and clean up waste versus values recovered.
This is an experiment, and can tell you a lot if you're on to something or wasting more money than you will profit from any values.

 

[VolkD]

I advise to keep track of the amount and costs of your acids, time spent to process and clean up waste versus values recovered.
This is an experiment, and can tell you a lot if you're on to something or wasting more money than you will profit from any values.

Of course, economics is an important aspect of the whole thing, especially if you want to make a business out of it. Well, I won't be doing business, I see it as a hobby. Nevertheless, I can try to at least partially evaluate the consumption and income.
So far, I've used 3.5l of hydrochloric acid - let's round it up to 4l and 230g of sodium persulfate - let's round it up to 250g. Electricity was minimal and I'll just ignore it. I've made four batches, and I'm combining the foils and ravinating them together. Only then will I know how much gold I've gained. The time spent is the most problematic. If you take this as a hobby, it's very difficult to put any value on it. If you take this as a business, then loss is probably guaranteed. In addition, when calculating the time spent, it's very difficult to take into account individual parts of the time when you're actually doing it and separate them from those when you could be doing something else, but you still have to be somehow prepared. Well, I don't have this problem, I have a pension for life, and the time I invest in this is pure joy.
For everyone else, it's something like this:
4l of hydrochloric acid a 1.6€ ............ 6.4€
0.25kg of sodium persulfate a 4€ .... 1€
So I've spent 7.4€ so far.