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Ausome: Non-Toxic Technology Extracts More Gold From Ore
https://scitechdaily.com ^ | OCTOBER 13, 2021 | By AALTO UNIVERSITY

Posted on 10/14/2021 6:17:45 AM PDT by Red Badger

Gold. Credit: Robert von Bonsdorff/Aalto University

Study shows new chloride-based process recovers 84% of gold compared to the 64% recovered with traditional methods.

Gold is one of the world’s most popular metals. Malleable, conductive and non-corrosive, it’s used in jewelry, electronics, and even space exploration. But traditional gold production typically involves a famous toxin, cyanide, which has been banned for industrial use in several countries.

The wait for a scalable non-toxic alternative may now be over as a research team from Aalto University in Finland has successfully replaced cyanide in a key part of gold extraction from ore. The results are published in Chemical Engineering.

Traditionally, once gold ore is mined from the ground, it’s crushed to a powder and passed through a series of tanks in a process called leaching. Cyanide is then used to separate the gold from the ore into the leached solution.

With the new process, the leaching and recovery process is done with chloride, one of two elements in table salt.

“Until now, no one has developed a good method for recovering small amounts of gold from industrial chloride solutions,” says Ivan Korolev, a researcher on the project and doctoral candidate.

“With our process, the amount of gold we’ve been able to recover using chloride is as high as 84%. In comparison, using the standard cyanide process with the same ore yielded only 64% in our control experiment,” he explains.

Called electrodeposition-redox replacement (EDRR), the new process combines the best of two common methods for extracting leached gold: electrolysis, which uses electric currents to reduce gold or other metals present in the leaching solution, and cementation, which adds particles of other metals to the solution to react with the gold. Professor Mari Lundström and University Lecturer Kirsi Yliniemi, from Aalto University’s School of Chemical Engineering, are behind its development.

“With EDRR, we apply short pulses of electricity to create thin layers of metal – in our case copper – on the electrode and cause a reaction that encourages gold to replace the copper layer by layer,” says Korolev. “The method has low energy consumption and doesn’t require the addition of any other elements.”

Industry-level collaboration The research was conducted as part of a broader EU sustainability project called SOCRATES, and the work was done in collaboration with Finnish mining-technology giant Metso Outotec. Most of the experiments were performed at the company’s research center in western Finland.

“Collaborating with Metso Outotec allowed us to develop the method in a way that’s much closer to real-world implementation,” says Korolev. “We started with about 9% recovery, but it then grew to 25%, and soon we were hitting 70% — sometimes we even achieved close to 95%.”

“It’s one thing to do an experiment like this on a small scale, but nobody had ever done it at the scale that we have done. We showed that even though our method is still really new, there is a lot of potential for making it a successful alternative to the traditional industrial process,” he says.

“Until now, no one has developed a good method for recovering small amounts of gold from industrial chloride solutions.” — Ivan Korolev

“The extraction methods of the past have always left some valuable metals behind. Now, as demand for metals grows all the time, even these small amounts are important,” he says. “I think we can still increase the yield with our EDRR technology. Perhaps we cannot reach 100%, but I believe we can hit the 90% mark or more.”

“It would be great to see a mining company interested in this technology and willing to test with their ore on site.”

Korolev has a very personal interest in the project too. Born in the Siberian mining town of Kemerovo, he grew up seeing both the positive and the negative sides of the industry. When studying mining engineering – first in Russia and then in several European universities – Korolev became interested in metallurgy and the recovery of waste materials.

“The extraction methods of the past always left some valuable metals behind. Now, as demand for metals grows all the time, even these small amounts are important,” he says. “I think we can still increase the yield with our EDRR technology. Perhaps we cannot reach 100%, but I believe we can hit the 90% mark or more.”

Reference: “Electro-hydrometallurgical chloride process for selective gold recovery from refractory telluride gold ores: A mini-pilot study” by Ivan Korolev, Pelin Altinkaya, Mika Haapalainen, Eero Kolehmainen, Kirsi Yliniemi and Mari Lundström, 8 September 2021, Chemical Engineering.

DOI: 10.1016/j.cej.2021.132283


TOPICS: Business/Economy; History; Military/Veterans; Science
KEYWORDS: aalto
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1 posted on 10/14/2021 6:17:45 AM PDT by Red Badger
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To: Red Badger

If this can be scaled, and is available to most soil/rock types, this could be usable for re-working old tailing piles...


2 posted on 10/14/2021 6:24:38 AM PDT by marktwain (President Trump and his supporters are the Resistance. His opponents are the Reactionaries. )
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To: marktwain

Yes.............................

Todd Hoffman is ecstatic!.....................


3 posted on 10/14/2021 6:31:24 AM PDT by Red Badger (Homeless veterans camp in the streets while illegal aliens are put up in hotels.....................)
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To: Red Badger

Terrific! Now, do lithium.


4 posted on 10/14/2021 6:42:45 AM PDT by MattMusson (Sometimes the wind blows too much)
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To: Red Badger

I know there are other alternatives to cyanide that involve either Bismuth or Lead for extraction, but I’m assuming the issue is that they are significantly more expense and/or don’t scale well.


5 posted on 10/14/2021 6:43:51 AM PDT by reed13k (For evil to triumph it is only necessary that good men do nothing)
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To: Red Badger

Tailing Piles here we come!


6 posted on 10/14/2021 6:44:27 AM PDT by MattMusson (Sometimes the wind blows too much)
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To: Red Badger
it’s used in jewelry, electronics, and even space exploration

...but it is especially valuable as currency.

They left that part out.

7 posted on 10/14/2021 6:47:32 AM PDT by Bon of Babble (Rigged Elections have Consequences)
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To: marktwain
If this can be scaled, and is available to most soil/rock types, this could be usable for re-working old tailing piles...

My first thought!

8 posted on 10/14/2021 7:10:01 AM PDT by null and void (As usual, the GOP was either totally unprepared for the onslaught or complicit in the tyranny)
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To: reed13k
...Bismuth or Lead or Mercury for extraction.

Try to get any of those past the rabid greenies!

Something that can be positioned as being like table salt or laundry bleach has a higher chance...

9 posted on 10/14/2021 7:17:45 AM PDT by null and void (As usual, the GOP was either totally unprepared for the onslaught or complicit in the tyranny)
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To: null and void

Right I knew lead had other unforgivables associated (forgot about mercury but same issue), but thought Bismuth was still viable....but likely still a heavy metal and thus verboten!

Thanks


10 posted on 10/14/2021 7:34:27 AM PDT by reed13k (For evil to triumph it is only necessary that good men do nothing)
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To: reed13k

But sooooothing pink Pepto-BISmol is still A-OK!


11 posted on 10/14/2021 7:47:38 AM PDT by null and void (As usual, the GOP was either totally unprepared for the onslaught or complicit in the tyranny)
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To: Red Badger

Soooo.... will this process work on old computer components or is that another process altogether?


12 posted on 10/14/2021 7:53:04 AM PDT by LastDayz (A blunt and brazen Texan. I will not be assimilated.)
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To: marktwain

I’m guessing it would also make it easier to reclaim gold from electronics.


13 posted on 10/14/2021 7:55:20 AM PDT by Ellendra (A single lie on our side does more damage than a thousand lies on their side.)
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To: Red Badger

No worries. The Hoffmans will find a way to screw it up.


14 posted on 10/14/2021 8:01:06 AM PDT by Noumenon (The Second Amendment exists primarily to deal with those who just won't take no for an answer. KTF)
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To: null and void
Something that can be positioned as being like table salt or laundry bleach has a higher chance...

Ah yes... handling HCl is JUST like salt water.

As a person who once spent my days producing NaCN, I guess I'd rather work around HCl. But, it's no daisy either.

15 posted on 10/14/2021 8:02:24 AM PDT by SomeCallMeTim ( The best minds are not in government. If any were, business would hire them!it)
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To: Ellendra
The problem with electronics is getting enough to make it viable.

Give me ten thousand tons of electronics, I will make money extracting the gold.

1 ton, not enough to be anywhere near viable...

16 posted on 10/14/2021 8:02:35 AM PDT by marktwain (President Trump and his supporters are the Resistance. His opponents are the Reactionaries. )
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To: LastDayz

You could use Aqua Regia for that..................


17 posted on 10/14/2021 8:03:54 AM PDT by Red Badger (Homeless veterans camp in the streets while illegal aliens are put up in hotels.....................)
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To: SomeCallMeTim

Try working with HF...


18 posted on 10/14/2021 8:26:01 AM PDT by null and void (As usual, the GOP was either totally unprepared for the onslaught or complicit in the tyranny)
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To: Red Badger
Old commercial: "There's nothing like the smell of an Aqua Velva Regia man!"
19 posted on 10/14/2021 8:29:43 AM PDT by 17th Miss Regt
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To: 17th Miss Regt

He would smell........DEAD.............................


20 posted on 10/14/2021 8:32:10 AM PDT by Red Badger (Homeless veterans camp in the streets while illegal aliens are put up in hotels.....................)
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