# Concentrated vinegar technology



## Patry0t

Stephen Foley is looking to get his hands on some gold… the problem is that it takes too much time, costs too much money and harms the environment.

The work of his research team—made up of Loghman Moradi, research associate, and Hiwa Salimi, PhD student— changes all of that.

“We’ve found a simple, cheap and environmentally benign solution that extracts gold in seconds, and can be recycled and reused,” said Foley, an associate professor in the Department of Chemistry. “This could change the gold industry.”

The problem with gold, explained Foley, is that it is one of the least reactive chemical elements, making it difficult to dissolve. That is why “artifacts discovered from 3,000 year ago still have gold on them.”

Given this difficulty, there are two main ways to get gold: through mining gold from the earth, which requires massive amounts of sodium cyanide; and recycling gold from secondary sources like jewelry or electronic scraps.

“The problem with mining has to do with the harsh environmental effects of the toxicity of cyanide that fills tailing ponds,” said Foley. “When one of the ponds breaks, it dumps the cyanide into nearby lakes or rivers and kills the environment.”

Recycling gold from jewelry or electronic scraps—think computer chips and circuits lined with thin layers of gold—is not without issue either.
Annually, Foley explained, the world produces more than 50 million tons of electronic waste per year; that amount is increasing rapidly due to non-stop innovation that shortens the life span of electronic devices.

Because of the lack of suitable recycling methods, he continued, more than 80 per cent of “e-waste” ends up in landfills, making it a pretty serious environmental issue.

There are two current industry standards for removing gold from electronic scraps. The first is pyrometallurgy, which burns the gold off using high temperatures. This method is energy intensive, cost prohibitive and releases dangerous gases, like dioxins.

The second is hydrometallurgy in which leaching chemicals like cyanide solution or aqua regia—Latin for king’s water, which is a mixture of concentrated nitric acid and hydrochloric acid—are used, a process Foley called “expensive, very toxic and completely non-recyclable.
“The environmental effects of current practices can be devastating,” said Foley.

Foley used the city of Guiyu, China, considered the e-waste capital of the world, as an example. Guiyu receives 100,000 tonnes of e-waste per day, and because of unregulated processing, Guiyu has the highest levels of dioxins for any city ever recorded. The result, he continued, is the majority of Guiyu’s residents have some form of neurological damage.

What Foley and his research team discovered is a process that extracts gold efficiently and effectively without any of the downfalls of current industry practices.

*“We use one of the most mass-produced chemicals: acetic acid; at five per cent concentration it’s plain table vinegar. We use a minute amount of an acid and an oxidant to finish our solution.”*

The solution, he continued, is the greenest solvent next to water, so eliminates the vast number of environmental concerns that come with long standing methods of gold extraction.

In this technique, the gold extraction is done under very mild conditions while the solution dissolves gold with the fastest rate ever recorded. “Gold is stripped out from circuits in about 10 seconds leaving the other metals intact” Foley said.

When time is factored in with lower toxicity and conse*quential effects, this new solution appears to be a natural replacement that could revolutionize the industry.

To highlight the improve*ment Foley’s solution presents, consider that it costs $1,520 to extract one kilogram of gold using aqua regia and results in 5,000 litres of waste. With the U of S solution it costs $66 to produce one kilogram of gold and results in 100 litres of waste that can be reused over again.

The other main advantage over current recycling processes, he continued, is that this specific solution is gold selective, meaning it only dissolves gold not other base metals, like copper, nickel, iron and cobalt, found in printed circuit boards.

“Aqua regia, for example, dissolves everything,” he explained, meaning that once dissolved, the gold still needs to be extracted from the solution and the other metals, and the solution gets saturated very quickly.

The next step for Foley and his team is to move the process into large-scale applications for gold recycling from gold-bearing materials.
By large-scale, Foley means very large.

“To extract three grams of gold from ore, you need one tonne of rock. We are not yet viable on a big scale like that,” he said, adding that to that end they are currently searching for industry partners.

Youtube:
https://www.youtube.com/watch?v=Wqql-5S8dm4

SOURCE 

SOURCE2

Any thoughts?


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## butcher

I may just be uneducated, and did not waste my time researching this or watching the video.
How can making a dilute form of aqua regia from an organic acid be safer or better than other methods?

I think it is a good selling point, but in the end not as true as many would like us to believe, the solution is not safer will not work as well as other methods...
If I cannot get an acid like HCl which if mixed with hydroxide will form something I could eat on my potatoes, then I may look to an organic weak acid like vinegar. 

But even then I would still have to properly treat the toxic waste from that vinegar process, which is not much different than the processes we use now. and organic acid could add some other issues some of which may become more dangerous in certain circumstances.

I have seen many new boxes of tricks, although interesting not much use practically in most cases.
Maybe this is some new kind of vinegar? To prove me wrong.
just call me Doubtful Debbie on this one.


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## FrugalRefiner

Patry0t said:


> *“We use one of the most mass-produced chemicals: acetic acid; at five per cent concentration it’s plain table vinegar. We use a minute amount of an acid and an oxidant to finish our solution.”*
> 
> Any thoughts?


I could dissect the post line by line and point out flaw after flaw, but I'll just focus on the one above, because we've discussed this "new solution" before, and I've made the same comment then.

Let's start with the acetic acid. I agree it's perfectly safe at low concentrations like vinegar, and I often use it when cooking.

The water I use when cooking flows through the copper pipes in my home, and it too is perfectly safe.

But if I put that same vinegar together with a piece of the copper pipe, and leave it open to the air we breathe (an oxidizer), it creates copper acetate. As with most copper salts, copper acetate is very toxic to virtually all living things. To make it worse, it is a permeator, meaning that if you get it on your skin, some of it will be absorbed into your system.

Like butcher, I'll stick with the tried and true methods we promote here on the forum.

Dave


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## anachronism

Patry0t said:


> To highlight the improve*ment Foley’s solution presents, consider that it costs $1,520 to extract one kilogram of gold using aqua regia and results in 5,000 litres of waste. With the U of S solution it costs $66 to produce one kilogram of gold and results in 100 litres of waste that can be reused over again.
> 
> 
> 
> Any thoughts?



Yes I have a thought - how do you quantify the above statement?


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## rickbb

Anytime the sales pitch consists entirely of how great it is, "fastest ever", "revolutionize the industry", and no words on how it actually works, you can bet it's all a load of hooey.

If it worked they wouldn't have to sell it at all, it'd sell itself.


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## rickbb

anachronism said:


> and results in 100 litres of waste that can be reused over again.
> 
> 
> 
> Any thoughts?



If it can be re-used over again, is it really waste?


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## anachronism

Rick the part I'm really looking to quantify is the 5000 litres of waste AR solutions to recover 1Kg of gold, along with the $1,520 cost. To be honest though, I'm not holding my breath waiting for an answer. 

Although I might be pleasantly surprised, I doubt he'll be back.


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## Patry0t

Unfortunately I don't know the answers either. I'm not to good at chemistry, but I have this new hobby, the precious metal recovery, and I found this article so I decided to share it here. 
I hope the article is true, because it is a product of a university's research, so I doubt that it is fake.


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## anachronism

That's fair. Excuse me I wrongly assumed you were trying to promote the method. I wonder where the university got their figures from.


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## butcher

Patry0t,
They come up with this kind of thing all of the time, there may be a use for it somewhere, maybe, like as an etchant in some electronic process or something. just because these study's come from a university doesn't always give them credentials in real world applications, or with what we do. will it work yes, but not well at all for what we do here, and several of the claims you stated are just plain bogus bull.

Just because someone patented something does not mean it works better than proven methods, although the patents always will claim they will. I have seen many patents of very common knowledge known and used thousands of years before it was written, they may have added or changed some minor twist, just to sell their wares.

This forum is better than any university I could think of when it comes to precious metal recovery and refining, the library of information here is better than most universities will have on their bookshelves.
I still say it is the best university in the world and registration is free.

Spend a couple of years here and you will soon begin to see what I am talking about.

Welcome to the best pace in the world to learn this field of chemistry.


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## nickvc

anachronism said:


> Patry0t said:
> 
> 
> 
> To highlight the improve*ment Foley’s solution presents, consider that it costs $1,520 to extract one kilogram of gold using aqua regia and results in 5,000 litres of waste. With the U of S solution it costs $66 to produce one kilogram of gold and results in 100 litres of waste that can be reused over again.
> 
> 
> 
> Any thoughts?
> 
> 
> 
> 
> Yes I have a thought - how do you quantify the above statement?
Click to expand...



Well I know some members pay well above the real cost for nitric but that is one big leap in costs, I'm sure I have had a kilo of gold dissolved in AR at well under 5 litres many many times and the cost qouted amounts to nearly 4% of the value of the gold....complete BS !


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## pp2kr

Acetic acid, HCL, H2O2 and CaCl2 goes well for palladium...At least my tests goes nice...


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## pp2kr

Today I performed another test with NaNo3 instead of NaCl2. Quit surprised with the reaction.
I could disolve a 4x4 mm gold sheet in 30 minutes at about 60C. The drawback is the smell...powerfull chlorine


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## g_axelsson

pp2kr said:


> Acetic acid, HCL, H2O2 and CaCl2 goes well for palladium...At least my tests goes nice...





pp2kr said:


> Today I performed another test with NaNo3 instead of NaCl2. Quit surprised with the reaction.
> I could disolve a 4x4 mm gold sheet in 30 minutes at about 60C. The drawback is the smell...powerfull chlorine


I guess one is a typo... which one?

Adding HCL and NaNo3 is what we call poor mans aqua regia on this forum and a well known process.

Göran


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## Patry0t

so this process is nothing new?


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## butcher

You will not find much new, that we have not thoroughly discussed. instead of trying to find "new" it is many times better to learn the older tried and tested methods, which have been developed through much more research than the new tricks.

Understanding the old methods gives a better understanding to develop further improvements or even sometimes a new method.


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## pp2kr

Hello

I agree that HCL+NaNo3 will be a poor man AR. However I'm trying a new way to get some results. Maybe I could be completly wrong. I just wish to *share *my experiments! I'm not telling anyone that my findings and errors are the right way to do!

But I'm learning with them! 8)


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## pp2kr

Ok guys.

You're sure! I will read more than post. I have a lot to learn!


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## Lou

Why doesn't someone ask him to come to the forum and explain:

http://artsandscience.usask.ca/profile/SFoley#/research


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## Topher_osAUrus

:!: 

Clever... Almost too clever..


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## Patry0t

Lou said:


> Why doesn't someone ask him to come to the forum and explain:
> 
> http://artsandscience.usask.ca/profile/SFoley#/research



Good idea!


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## FrugalRefiner

Patry0t said:


> Lou said:
> 
> 
> 
> Why doesn't someone ask him to come to the forum and explain:
> 
> http://artsandscience.usask.ca/profile/SFoley#/research
> 
> 
> 
> Good idea!
Click to expand...

Since you posted the information, we'll allow you the honor.

Dave


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## richoc

I spoke about using this to strip clean P C B s, got wiped off here.
Was using it to take off solder, but I went farther.
I do not go after the gold with it, I am going after the copper under the gold.
AP system with air coil I made, leaves gold foils nice and clean.
But slow, very slow, so found ways to speed it up.
Lots of copper to recover in the end also.

Now go at just exposed gold, leave the rest of the trace in place.
I have dreamed of this.

But this acid concentrated is a Deadly.
You should see the reaction at high concentration,wow.

I am going the next step now that I am able to work again.
Will report back findings.


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## galenrog

Your thread that you claim is missing is still here, Richoc. Do a search of your own posts and you will find it.


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## ZombieScrapper

I've watched this video a few times in the past. Even left a response. No description really just a look at my magic formula kind of video. Doesn't or didn't answer comments (but haven't looked lately) thought it was kinda neat being as its from university of Saskatchewan up here in my country, but seems a little fishy to me some how. Idk, would be nice to have a simple and safe method though. 


Sent from my iPhone using Tapatalk


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## hkhogold

https://www.google.com.hk/patents/US8663584?dq=loghman+moradi&hl=zh-TW&sa=X&ved=0ahUKEwjGt975tYjPAhUDJZQKHbQTCWEQ6AEIGTAA
The method here about seem like didnt about vinegar .


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## g_axelsson

hkhogold said:


> https://www.google.com.hk/patents/US8663584?dq=loghman+moradi&hl=zh-TW&sa=X&ved=0ahUKEwjGt975tYjPAhUDJZQKHbQTCWEQ6AEIGTAA
> The method here about seem like didnt about vinegar .


It is a patent for liquid-liquid extraction of gold and palladium at the same time from an acidic solution.

Göran


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## Patry0t

don't wanted to write another post about it. Just another university claiming a new and eco-friendly way to extract gold from e-waste. I will post it here:
http://www.ed.ac.uk/news/2016/gold-from-phones-becomes-real-prospect

We should watch what happens next.

Edit:
I found the article too, but we have to pay to read it..
http://onlinelibrary.wiley.com/doi/10.1002/anie.201606113/abstract


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## Geo

When it trickles down to the hobbyist refiner, let me know. There was a time when you had to pay for a college degree (or two) to get the knowledge I have gotten from this forum alone for free. As long as people want to keep their magic water secret, I'll stick with tried and true.


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## Topher_osAUrus

Geo said:


> When it trickles down to the hobbyist refiner, let me know. There was a time when you had to pay for a college degree (or two) to get the knowledge I have gotten from this forum alone for free. As long as people want to keep their magic water secret, I'll stick with tried and true.



+1 times 1000000

Universities want money to come in to keep on keep'n on...
Pretty easy to do that if people think you have found the magic bullet, eh?


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## Patry0t

I found another piece of information:

http://www.cbc.ca/news/canada/saskat...aste-1.3424573


> "They were investigating concentrated vinegar as a solvent, and they found that they could use this solvent, with a few minor additions of extra chemicals in there, to be a very efficient solvent for stripping gold off of circuit boards," he said.
> *The gold comes out in an oxidized form solution, but the team added zinc which makes it a solid.*
> Foley said, for chemists, it's actually quite a simple process and happens in seconds.


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## bemate

Patry0t said:


> don't wanted to write another post about it. Just another university claiming a new and eco-friendly way to extract gold from e-waste. I will post it here:
> http://www.ed.ac.uk/news/2016/gold-from-phones-becomes-real-prospect
> 
> We should watch what happens next.
> 
> Edit:
> I found the article too, but we have to pay to read it..
> http://onlinelibrary.wiley.com/doi/10.1002/anie.201606113/abstract



Figured I would start off in here by contributing: The article is attached as a pdf, but it doesn't provide much except a structural formula. They consistently call the compund L, but the structure makes it possible to identify it. It's been way too long since I took my organic chemistry courses for me to bother trying to find its proper IUPAC name, and that will only provide so much anyway. Those of you in here with more experience can have a look and see if it provides something new, though I doubt it...

B


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## Patry0t

yes, interesting. I'm also waiting for the pros! I'm curious! No clue what that "L" is.


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## Patry0t

Patry0t said:


> yes, interesting. I'm also waiting for the pros! I'm curious! No clue what that "L" is.



No one??


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## Deano

Vinegar is effectively acetic acid with processing contaminants.

Acetic acid is the solvent for metals in the TCLP environmental test for metal solubility and mobility.

Acetic acid on its own will not dissolve gold.

Careful reading of the blurbs indicates that the process is yet another academic effort to get or maintain funding by publishing articles.

Note the use of phrases like "with the minor addition of some other chemicals" which indicates that these additions are what the author considered to be minor, not what prospective users might consider minor.

The most likely scenario is that the acetic acid is used to dissolve base metals away from the gold and so prevent them either limiting the gold solvent's access to the gold or, by forming acetate complexes with the base metals, putting them in a soluble form where they will not react with other reagents used in the process.

The actual gold solvent used is not revealed in the articles.

The reagent 'L" is a primary amine used for recovery of the gold from the solution, think a version of organic extraction.

As a primary amine it will only accept gold complexes when it is protonated which means it has to operate in acid conditions.

Vinegar is an acid solution so the amine will efficiently adsorb gold complexes from these solutions.

The amine has absolutely no role to play in the dissolving of the gold in the first place, it is there purely as a recovery agent.

Deano


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## pp2kr

Hiwa's article "Gold Leaching in Organic Solvents: Simple and Milde Reaction Conditions for Fast Gold Dissolution" is avaliable in http://libgen.io/ in full. Just search for it.

However they used THF but Acetic acid could be used. I have seen a poster claiming by one of the team they used Acetic acid, HCL, H2O2 and CaCl2 for palladium at high rates. Maybe a clue maybe not....


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## g_axelsson

pp2kr said:


> Hiwa's article "Gold Leaching in Organic Solvents: Simple and Milde Reaction Conditions for Fast Gold Dissolution" is avaliable in http://libgen.io/ in full. Just search for it.
> 
> However they used THF but Acetic acid could be used. I have seen a poster claiming by one of the team they used Acetic acid, HCL, H2O2 and CaCl2 for palladium at high rates. Maybe a clue maybe not....


That paper describes measuring the gold dissolving speed with HCl and H2O2 mixed in different organic solvents. It's a purely academic work to compare some different organic solvents and it can give some clues about how it exactly works, but for practical refining work I don't see any application.

The reaction was measured on gold powder without any other solid substances or metals present.

The process of dissolving gold with hydrochloric acid and hydrogen peroxide is well known and I have used it myself sometimes. The only thing worth noting is that more than 1M HCl and 0.2M H2O2 doesn't speed up the process. The speed were also compared to cyanide, aqua regia and a number of other solvents. There were also some references that could be worth following up on.

Göran


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## Patry0t

thank you for looking into it Göran.


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## pp2kr

http://artsandscience.usask.ca/chemistry/news/article.php?articleid=573

In the second process, a comprehensive set of water-miscible organic solvents including small amounts of *HCl, CaCl2* and some *oxidizing reagents* were used as new leaching systems for gold. Among all studied solvents, *acetic acid* provided the highest gold dissolution rates reported to date. Along with an unmatched gold dissolution rate, this new leaching system was also highly selective for gold over base metals such that in the case of electronic scraps, more than 99% of gold was extracted from printed circuit boards (PCBs) in less than 20 seconds (which is the fastest known gold recycling process from e-waste ever reported) while less than 1.5% of nickel, 0.3% of copper, and 0.05% of all of the other base and heavy metals were leached during the same contact time. This new discovery promises to replace highly hazardous chemicals commonly used for gold recovery and opens new opportunities into the field of gold extraction for future studies

Maybe, maybe....the key is the oxidant....who's know?


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## bemate

I took a closer look at this today, and one word stood out to me: dithiobiuret. They are using derivatives of this compound added to the acidic solution, and my guess is this is the active ingredient in question. Problem is, depending on the specific derivate they use, dithiobiuret is highly toxic, probably because of the various C-S and C-N bonds.

The way I read this is that it's simply a slightly improved version of cyanide leachning for all practical intents and purposes. Still highly toxic, and why their process does not produce waste of the same scale as ordinary cyanide leaching is not clear to me. They do, however, give away very little specific information, likely to protect future patents they are planning, but until we know more it's hard to say anything other than that it seems a bit too good to be true, which it usually is...


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## pp2kr

bemate
This is for the first method. He presents two methods: (i) simultaneous leaching and solvent extraction and (ii) gold leaching in acidified water-miscible organic solvents. 8) 

I have found a study stating that nickel in insoluble in acetic acid but didn't find much about base metal...


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## frontiermetals

It's disappointing to read so many posts on this thread stating how there's nothing new about this process or how tried and true methods are the only way to go and so on. Have you guys watched the video? That's what blew me away... In a matter of seconds, the gold layer on boards was stripped away, leaving the base metals behind. This is HIGHLY selective and FAST, unlike almost all other methods discussed and presented here on hundreds of threads. These guys are not some con artists. They are professors at the University of Saskatchewan for crying out loud. If you haven't watched the video, here it is again: 
https://www.youtube.com/watch?v=Wqql-5S8dm4


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## dragoneproducts

Patry0t said:


> Stephen Foley is looking to get his hands on some gold… the problem is that it takes too much time, costs too much money and harms the environment.
> 
> The work of his research team—made up of Loghman Moradi, research associate, and Hiwa Salimi, PhD student— changes all of that.
> 
> “We’ve found a simple, cheap and environmentally benign solution that extracts gold in seconds, and can be recycled and reused,” said Foley, an associate professor in the Department of Chemistry. “This could change the gold industry.”
> 
> The problem with gold, explained Foley, is that it is one of the least reactive chemical elements, making it difficult to dissolve. That is why “artifacts discovered from 3,000 year ago still have gold on them.”
> 
> Given this difficulty, there are two main ways to get gold: through mining gold from the earth, which requires massive amounts of sodium cyanide; and recycling gold from secondary sources like jewelry or electronic scraps.
> 
> “The problem with mining has to do with the harsh environmental effects of the toxicity of cyanide that fills tailing ponds,” said Foley. “When one of the ponds breaks, it dumps the cyanide into nearby lakes or rivers and kills the environment.”
> 
> Recycling gold from jewelry or electronic scraps—think computer chips and circuits lined with thin layers of gold—is not without issue either.
> Annually, Foley explained, the world produces more than 50 million tons of electronic waste per year; that amount is increasing rapidly due to non-stop innovation that shortens the life span of electronic devices.
> 
> Because of the lack of suitable recycling methods, he continued, more than 80 per cent of “e-waste” ends up in landfills, making it a pretty serious environmental issue.
> 
> There are two current industry standards for removing gold from electronic scraps. The first is pyrometallurgy, which burns the gold off using high temperatures. This method is energy intensive, cost prohibitive and releases dangerous gases, like dioxins.
> 
> The second is hydrometallurgy in which leaching chemicals like cyanide solution or aqua regia—Latin for king’s water, which is a mixture of concentrated nitric acid and hydrochloric acid—are used, a process Foley called “expensive, very toxic and completely non-recyclable.
> “The environmental effects of current practices can be devastating,” said Foley.
> 
> Foley used the city of Guiyu, China, considered the e-waste capital of the world, as an example. Guiyu receives 100,000 tonnes of e-waste per day, and because of unregulated processing, Guiyu has the highest levels of dioxins for any city ever recorded. The result, he continued, is the majority of Guiyu’s residents have some form of neurological damage.
> 
> What Foley and his research team discovered is a process that extracts gold efficiently and effectively without any of the downfalls of current industry practices.
> 
> *“We use one of the most mass-produced chemicals: acetic acid; at five per cent concentration it’s plain table vinegar. We use a minute amount of an acid and an oxidant to finish our solution.”*
> 
> The solution, he continued, is the greenest solvent next to water, so eliminates the vast number of environmental concerns that come with long standing methods of gold extraction.
> 
> In this technique, the gold extraction is done under very mild conditions while the solution dissolves gold with the fastest rate ever recorded. “Gold is stripped out from circuits in about 10 seconds leaving the other metals intact” Foley said.
> 
> When time is factored in with lower toxicity and conse*quential effects, this new solution appears to be a natural replacement that could revolutionize the industry.
> 
> To highlight the improve*ment Foley’s solution presents, consider that it costs $1,520 to extract one kilogram of gold using aqua regia and results in 5,000 litres of waste. With the U of S solution it costs $66 to produce one kilogram of gold and results in 100 litres of waste that can be reused over again.
> 
> The other main advantage over current recycling processes, he continued, is that this specific solution is gold selective, meaning it only dissolves gold not other base metals, like copper, nickel, iron and cobalt, found in printed circuit boards.
> 
> “Aqua regia, for example, dissolves everything,” he explained, meaning that once dissolved, the gold still needs to be extracted from the solution and the other metals, and the solution gets saturated very quickly.
> 
> The next step for Foley and his team is to move the process into large-scale applications for gold recycling from gold-bearing materials.
> By large-scale, Foley means very large.
> 
> “To extract three grams of gold from ore, you need one tonne of rock. We are not yet viable on a big scale like that,” he said, adding that to that end they are currently searching for industry partners.
> 
> Youtube:
> https://www.youtube.com/watch?v=Wqql-5S8dm4
> 
> SOURCE
> 
> SOURCE2
> 
> Any thoughts?


I am by no measure, a 'chemist.' As a prospector of only 5 years, I was told that simple table salt and vineger would clean my gold. It works. I also dabbled with some old organ parts and used vinegar to dissolve the plastic from the values. In retrospect, of the idea, that it could work in the mining industry, it just adds another step too the refining process. In other words if I have a ton of material, with values ranging from copper to iridium/osmium, everything still needs to be processed. Could it work, simply for gold, I would think so. But, then you have some other form of pregnant liquid too deal with. One pregnancy is tuff enuff to deal with[emoji7] If I contemplate the steps. 1 gather values. 2 roast values.
3 separate larger values.
4 assay values for toxics/radioactivity
5 proceed with hydrochloric and nitrics.
6 separate with reagents.
7 forge disiered values.

Using the viniger is only going to extract surface gold, from a prospectors concentrate point of view. Maybe it would be useful to quickly purify an amount of values from concentrate, but then, what is the reagent? I'm a novice; intuitive, but not nearly experienced enough to give guidance or advice....


Sent from my X301 - Locked to Life Wireless using Tapatalk


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## rickbb

_ "The other main advantage over current recycling processes, he continued, is that this specific solution is gold selective, meaning it only dissolves gold not other base metals, like copper, nickel, iron and cobalt, found in printed circuit boards." _

Doesn't this violate some basic law of chemistry? Wouldn't an acid strong enough to dissolve gold also dissolve everything above it in the reactivity scale?

How can you dissolve gold off a PCB without dissolving the copper it's plated on? I could understand it if it was a time thing, dip in in solutions for an exact amount of time to get the gold off then pull it before the copper starts, but that seems a bit dubious to me.


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## Platdigger

Well, cyanide becomes fairly selective to gold at the right concentrations.
Also this type of thing can happen with the use of certain buffers when using acids.
Perhaps we should ask Deano if thiocyanate would act like this.


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## Deano

Thiocyanate reacts with copper to form an insoluble complex, unless you keep removing this layer as it forms there is only am monolayer of copper complexed.

Exactly what they are defining as an acid is the key to their processing.

Vinegar on its own is a relatively mild reagent but will complex with most metals at a slow rate.

My thoughts are that the vinegar is there purely to provide the acid environment in which the actual gold solvent and gold complexes so formed exists.

Vinegar is used probably because of its cheapness.

The actual gold solvent would then be something like selenic acid or similar or a derivative there from.

The cost of these solvents is high so the idea of having a cheap acid set the conditions where the expensive acid and corresponding complexes is stable is fairly obvious.

Adding an oxidiser would speed up the gold leaching rate more than the copper leaching rate, thus justifying the carefully worded claims.

Deano


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## aga

I did some experiments with salt, vinegar, hydrogen peroxide and bleach a while back.
The 'trick' is to maintain the pH in the correct range as the reaction proceeds.
http://www.sciencemadness.org/talk/viewthread.php?tid=63606&page=2#pid419451

While a 'correct' balance of ingredients does actually dissolve gold, it is very slow compared to HNO3.

Probably the most useful result was getting the gold foils off RAM fingers with just salt, vinegar and 3% H2O2.

With the foils filtered out and then dissolved normally, this method could save on the costs and dangers of using HCl/HNO3 for every step. 

For example, the volume of aqua regia required in the next step (to dissolve the foils) could be much smaller.

The advertised 'magic bullet' solution is probably hookum.


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## Fireflymetals

Ok, so I did some serious digging round the interwebz...

I found the actual process. while I understand the statements. I am not exactly a pro at the gold side of things, here is hoping that Deano has better perspective.

I am however going to set up and lab this one to see what it looks like results wise.

http://www.rexresearch.com/foleygold/foleygold.html

--L


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## Deano

My comments on the leaching side still stand.

All gold leaches require a source of energy and some form of complexant to keep the gold in solution.

The first blurb says that they are using hydrogen peroxide as the energy source and an unknown acid as the complexant.

The actual role of the vinegar is not revealed.

It really has two possibilities, firstly to dissolve base metals cheaply to allow the leach access to the gold, secondly to establish acid conditions cheaply so that a complexant which operates in acid conditions needs only a small amount of this complexant for the conditions to be suitable.

Assuming that the article is totally factual then the complexant is limited to acids which can form complexes with gold.

The obvious first one is hydrochloric acid but the gold complexant part of hydrochloric acid is the chloride. This could be cheaply substituted with common salt, sodium chloride.

As sodium chloride is not mentioned it may have been deliberately left out in the ingredients list.

Assuming that the article has no omissions in the ingredients listings, you are then left with any acid forms of gold complexants as the mystery substance.

This can range from actual single acids such as selenic acid which can dissolve gold to known gold complexants such as iodine in the form of hydroiodic acid etc.

Disappointing as it may seem, there are only new versions of known gold processes being put forward as being new and revolutionary.

Many of these new versions are clever and show good chemistry understanding.

The one thing about all of them is that none have been adopted by industry.

If they were all so good and cheap and robust then they would have replaced cyanide and chloride leaching in the mining and recycling industries.

Deano


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## pp2kr

Deano

They cited HCL and CaCl2...I don't know the CaCl2's roles in the process but should be a starting point(guessing!!!) to look...


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## Deano

The only role calcium chloride can play is as a source of chloride ions in place of sodium chloride referenced above.

Deano


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## mark.balcorp

Deano said:


> The only role calcium chloride can play is as a source of chloride ions in place of sodium chloride referenced above.
> 
> Deano



Hello, 

I am new to this forum and gold extraction, though have been researching the space quite a bit as of recent. The company I work for was approached by a company claiming to have a (green) proprietary acid leach solvent extraction method that has been optimized for to ultra-fine gold extraction applicable to extraction of gold in the mining industry (specifically to fine gold trapped ore tailings). 

The company claims their leach solvent is able to recover gold at a 99% purity, and outperforms environmentally hazardous standard methods in the mining industry, like CN extraction used on ore and tailings, in terms of both cost and %recovery (98% recovery stated for trapped ultra fine (ppm) gold in tailings). They also claim the tech to be scalable to industry application, and has already been done by them. Thus going forward I will be attempting to verify this the best I can, and will be evaluating the tech for specifically for application in an e-waste recycling business model (focused upon gold extraction with this tech). So upon receiving verifiable details on the tech's gold %percent recovery (as applicable to e-waste gold extraction), scalability specifics, and a detailed cost-analysis - I will want to run a financial analysis and a critical competitive analysis. 

Thus I was wondering if anyone has knowledge of the current processes (both green and not) that are most used and widely accepted as the best method for extracting gold from E-waste based mainly on the endpoint of generating the most profit (thus considering scalability). From my research AR variant procedures seem to be the most widely accepted on the basis of cost and environmental safety - though as mentioned I am new to the space. 

Going forward, I am in need of cost and performance spec estimates for current industry optimal and standard methods, as per scale, for extracting gold from e-waste [$/ton of E-waste (for general e-waste and/or PCB waste) and %recovery of gold content and %purity of gold content recovered].

Any insight, information, or even direction to sources of expertise where I can find these answers would be much appreciated. Even rough estimates at small scale would be helpful.

Thank you,

Best,
Mark


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## pp2kr

Below is the fresh patent of Hiwa. I think it's another method. Not acetic acid process. Yet...

https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2016168933&recNum=2&maxRec=3&office=&prevFilter=&sortOption=Pub+Date+Desc&queryString=ALL%3A%28hiwa+salimi%29&tab=PCTDescription


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## aga

mark.balcorp said:


> Going forward, I am in need of cost and performance spec estimates for current industry optimal and standard methods, as per scale, for extracting gold from e-waste [$/ton of E-waste (for general e-waste and/or PCB waste) and %recovery of gold content and %purity of gold content recovered].


I get the impression that you're asking experienced gold refiners for the precise data regarding their efficiency and recovery rates.

If so, it is very unlikely that anyone will answer, as those figures are the basis of their livelihoods.

Your best bet is to take a random sample of the expected scrap for your business model and process it yourself, empirically.

All the details of How that is done can be found on this forum.

That way you will have exact data for each scrap type that your plan encompasses.

There never has been, probably never will be, a Single method for all scrap types.


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## anachronism

mark.balcorp said:


> Thus I was wondering if anyone has knowledge of the current processes (both green and not) that are most used and widely accepted as the best method for extracting gold from E-waste based mainly on the endpoint of generating the most profit (thus considering scalability). From my research AR variant procedures seem to be the most widely accepted on the basis of cost and environmental safety - though as mentioned I am new to the space.
> 
> Going forward, I am in need of cost and performance spec estimates for current industry optimal and standard methods, as per scale, for extracting gold from e-waste [$/ton of E-waste (for general e-waste and/or PCB waste) and %recovery of gold content and %purity of gold content recovered].
> 
> Any insight, information, or even direction to sources of expertise where I can find these answers would be much appreciated. Even rough estimates at small scale would be helpful.



Mark 

Some of us on here do have deals directly with refineries. The knowledge that comes from those costs hundreds of thousands of dollars of investment and experimentation and sampling to learn. My recommendation to you would be to talk to all the refineries applicable to you, compare their rates, get references, and start sending your batches in and in that way you will get your yield data. Don't get hung up on the 1 or 2 percents - get hung up on the overall cost of doing the business because it doesn't matter WHAT they charge if they don't recover all your precious metals......

Jon


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## someguy2

pp2kr said:


> Below is the fresh patent of Hiwa. I think it's another method. Not acetic acid process. Yet...
> 
> https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2016168933&recNum=2&maxRec=3&office=&prevFilter=&sortOption=Pub+Date+Desc&queryString=ALL%3A%28hiwa+salimi%29&tab=PCTDescription



I read over this patent and it does appear to be the process used in the video and news releases. If you look at the tables in the latter section of the patent the solution their using is a 1.5M HCl 0.6M H2O2 and 0.6M CaCL solution in an acetic acid solvent.

I have reproduced this and you can see my results blow:

http://imgur.com/a/dLkba

I used 99.7% glacial acetic acid, 31.45% HCl, 35% H2O2 and CaCl anyhydrous. This was my first attempt at doing this and would like to hear some feedback from some of the other members that have some more chemistry experience.

I have not yet attempted to drop the gold out of solution yet.

As a follow up this is what I did to create a 500mL solution.

1.5M HCl @ 31.45 w/w = 75mL
0.6M H2O2 @ 35 w/w = 20mL
0.6M CaCl = 33g

I added the HCl to 125mL of 99.7% glacial acetic after I added another 125 mL and 20mL H2O2 then diluted the solution to 500mL finally adding the CaCl. 

I stirred this for about 5 minutes and noticed the solution rose in temperature to about 35 degrees Celsius. After 10 minutes I added a single ram stick with the flat packs removed and saw the gold leached off within 3 minutes.

If someone would double check my calculations it would be very helpful.

Thanks


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## aga

The photo is a bit confusing - is that the foil removal step, or the gold dissolution step ?

As i recall, i did both without GAA, using just 8% OTC vinegar.


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## someguy2

aga said:


> The photo is a bit confusing - is that the foil removal step, or the gold dissolution step ?
> 
> As i recall, i did both without GAA, using just 8% OTC vinegar.



The gold foils are removed by directly leaching into solution as this solution is "Gold selective'. Other methods rely on dissolving the metals behind the gold plating to produce the gold foils and leaving the gold as a solid. Does this answer the question?

The patent posted above describes using GAA and H2O and the appear to getting a faster dissolution of gold using less dilute acetic acid.


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## aga

someguy2 said:


> 1.5M HCl @ 31.45 w/w = 75mL
> 0.6M H2O2 @ 35 w/w = 20mL
> 0.6M CaCl = 33g
> 
> I added the HCl to 125mL of 99.7% glacial acetic after I added another 125 mL and 20mL H2O2 then diluted the solution to 500mL finally adding the CaCl.
> 
> I stirred this for about 5 minutes and noticed the solution rose in temperature to about 35 degrees C.
> If someone would double check my calculations it would be very helpful.


For the acid and the peroxide, using w% concentrations and then measuring milli-litres makes no sense.
Use weight when it's concentration is in weight-percent, use volume when it's concentration is in molarity [M]. Need the density to work out the moles otherwise.

The 'recipe' sounds highly dubious if this comes from a Chemistry write-up.

Assuming the density of water, i.e. 1, 75mls of 31.45w% HCl would be 0.65 Moles of HCl.
20ml of 35 w% H2O2 would be 0.206 Moles of H2O2.

Calcium chloride is rarely anhydrous - it needs to be heated to melting point and then cooled in a water-free atmosphere to achieve that. It rips water from the air so well that it will turn to a puddle if left exposed ( i.e. it is deliquescent).

33g of truly anhydrous CaCl2 would be 0.297 Moles. 

When it is added to water, the dissolution is exothermic, i.e. it gets hot, same as dissolving NaOH does.


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## someguy2

Thanks for the feedback Aga, I am new to this whole thing so I do appreciate it. 

My 'recipe' could very well be incorrect. I am just reporting on what I did and what the effect was.

In terms of the Molarity and volume used for the HCl could you explain in further detail?

What I did was having a 31.45% 20 baume solution I calculated it was a 10M solution. If I want to add it to the acetic acid to have it at 1.5M for 500ml should I not be adding 75mL?


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## aga

Molarity is a measure that tells you how *many *atoms or molecule are in a volume of a solution.

W% tells you how much of the *weight *of a solution is those atoms or molecules.

I can think of only 1 reason why you have mentioned at this late stage the defunct Baumé scale, which was only made known (to me at least) on this site recently.

Google a little to find further answers relating to the Chemistry calculations required.


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## someguy2

There has been a follow up article posted by the local newspaper. It seems Dr Foley is going to be attempting to do a mobile based processing plant with this technology.

http://thestarphoenix.com/business/local-business/i-was-completely-unprepared-for-the-craziness-u-of-s-chemist-surprised-by-reaction-to-innovative-gold-company


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## Patry0t

thanks, for the update!


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## Xdoorsx

I just recently watched the video in question the only part i was the oxidizet. I dont know if anyone notice the temperature of the hot plate. Which is what i believe speads up the process of sepersting the gold from the base metal. From the video i watch the solution was preheated to 675 ° , then they turned it to the off position before putting the curcuit board into the solution.

I also saw a video. That clame you can completely etch all of the metal from circuit bosrds in like 5 minute. This was done using a plastic container with 2 parts hydrogen peroxide and 1 part muric acid. Alway adding the muric to the hydro.and not the otherway around. The you fill anothe container with hot water and boil it in the microwave. No you pkace the container with the solution into tge container of water. So the the first one floats in the other. Pkace the circuit boards into the solution and begin rocking the container up and down slowly so that the solution washes over the boards and stays agitated. Again without thethe container of hot water this process would be the ssme as all te others.


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## Snodigator

I put a ram bnoard with gold on it and a cpu with gold in a glass container overnight. The ram board i had broken in half to fit under the liquid. I used 6% and 3% combination hydrogen peroxide. It looks like there are flakes of something in the water and they are gold in color but it looks like shillac to me. It doesnt look like those gold specs from panning. Any feedback thank you.


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## Snodigator

Xdoorsx said:


> I just recently watched the video in question the only part i was the oxidizet. I dont know if anyone notice the temperature of the hot plate. Which is what i believe speads up the process of sepersting the gold from the base metal. From the video i watch the solution was preheated to 675 ° , then they turned it to the off position before putting the curcuit board into the solution.
> 
> I also saw a video. That clame you can completely etch all of the metal from circuit bosrds in like 5 minute. This was done using a plastic container with 2 parts hydrogen peroxide and 1 part muric acid. Alway adding the muric to the hydro.and not the otherway around. The you fill anothe container with hot water and boil it in the microwave. No you pkace the container with the solution into tge container of water. So the the first one floats in the other. Pkace the circuit boards into the solution and begin rocking the container up and down slowly so that the solution washes over the boards and stays agitated. Again without thethe container of hot water this process would be the ssme as all te others.


I wouldnt put in the microvwave it might spark or catch fire. Metal isnt meant to go in the microwave.


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## anachronism

Snod you can actually happily melt gold in a microwave if you build the correct housing for it. Surprising but true 8) 8)


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## lasseff

pp2kr said:


> http://artsandscience.usask.ca/chemistry/news/article.php?articleid=573
> 
> In the second process, a comprehensive set of water-miscible organic solvents including small amounts of *HCl, CaCl2* and some *oxidizing reagents* were used as new leaching systems for gold. Among all studied solvents, *acetic acid* provided the highest gold dissolution rates reported to date. Along with an unmatched gold dissolution rate, this new leaching system was also highly selective for gold over base metals such that in the case of electronic scraps, more than 99% of gold was extracted from printed circuit boards (PCBs) in less than 20 seconds (which is the fastest known gold recycling process from e-waste ever reported) while less than 1.5% of nickel, 0.3% of copper, and 0.05% of all of the other base and heavy metals were leached during the same contact time. This new discovery promises to replace highly hazardous chemicals commonly used for gold recovery and opens new opportunities into the field of gold extraction for future studies
> 
> Maybe, maybe....the key is the oxidant....who's know?



i really dont see this helping the environment in any way unless they give this info to the public freely :?


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## im1badpup1

I deleted my post because i can sum up whats going on in a far shorter way.

They know far more about the reaction process and are only showing a fraction of it and detailing even less. Its misrepresenting and misleading in effect.

One thing what may be of interest and true is that this process can be adapted to extract gold etc cheaper, without as much special licensing chemical controls and producing less hazardous waste.

But they cant patent that nor make money from it unless ppl agree to pay for it. And it is easy enough with readily available chemicals to do at home.


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## pp2kr

resurrecting the topic.
I have done some experiment with HCL and CaClO2 with good results. 
I've read the thesis(now blocked again). Quite promising


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## pp2kr

The thesis by google: 

https://core.ac.uk/download/pdf/226131006.pdf


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## Geo

Peracetic acid is dangerous when mixed with certain salts and even by itself. Mixing organic chemistry and mineral chemistry can lead to unstable compounds.


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