Glycine method

[samuel-a]

Hello Sam
Tell us about your results!

pp2kr

The short version... it didn't really worked.
Perhaps some dissolution of gold, but not enough to make it a viable option..

 

[pp2kr]

Hello Sam
Post your long version or PM me please!

pp2kr

 

[Craig A]

Sam,, I am currently building a leach tank(4000 Ltr) , heated and insulated for au reduction in Glycine. it would be interesting to share notes on ur failures,,, success's in your trial. Btw ,, we dont have a Cu problem, will be using Hydrogen peroxide for di-oxy,, CuSO4 ( 4 nMol) 1 Mol Glycine. running thru a carbon collumn . cheers

 

[Fireflymetals]

There is a process for leeching using glycine, It looked a bit to me at a first glimpse as what they were aiming at.

A leeching process in the right PH range and at the right temp would work about that fast...

I will run this up in the lab tomorrow after my normally scheduled tomfoolery and see what happens. I think I have some glycine around...

Oh, and howdy guys, been reading for a while, never actually posted. I am rather impressed. I actually studied BioChem postgrad and well, ::coughs:: I hate to admit I am rather dodgy on actual knowledge of inorganic processing. I was more aimed at bio research, it has been lovely dusting off the cobwebs with you lads.

--L

 

[g_axelsson]

Hi Fireflymetals and welcome to the forum.

Since your post mentioned glycine, I moved it to the glycine thread.

There are a couple of papers written about glycine leach, but it seems it isn't so specific to gold only.

Some articles that can be found via sci-hub.ac :
"The leaching of gold, silver and their alloys in alkaline glycine-peroxide solutions and their adsorption on carbon", E.A. Oraby, J.J. Eksteen, 2014, doi: 10.1016/j.hydromet.2014.12.015
"The selective leaching of copper from a gold–copper concentrate in glycine solutions", E.A. Oraby, J.J. Eksteen, 2014, doi: 10.1016/j.hydromet.2014.09.005

Looks like they are experimenting with it in Australia.

Let us know how it goes, so far I haven't heard anyone else trying glycime on the forum.

Göran

 

[g_axelsson]

I found open sources of two interesting papers.

The Selective Leaching of Copper from a Gold-Copper Concentrate in Glycine Solutions, E.A. Oraby and J.J. Eksteen, December 2014
The leaching of gold, silver and their alloys in alkaline glycine-peroxide solutions and their adsorption on carbon, E.A. Oraby and J.J. Eksteen, December 2014

Göran

 

[Fireflymetals]

So, while I have tonnes of odd things in my kit, I did not have glycine...

I ordered it and it showed up today, was packing things up to wander into the lab and got a call informing me that there was no power in the building, so results will be delayed.

I played a bit with modeling software (it never answers anything but it gives you good basal parameters).

Long story short, the answer is delayed...

I was planning on answering in the other thread (thanks for moving this), I also found datum I will post over there.

In any case I will keep you all appraised of what comes from this, I expect to have the experiment up and running in about 48 hours.

For datum points however I will run down what the process is going to be:

I have 4 items up on this weeks bench.

For testing I have 40kg of tight trimmed gold fingers. (I hear people having problems sourcing volumes of items. I don't know why I found that part easy but there ya go).


Glycine leaching: Testing 500 grams, looks like I will be working in a 5l beaker and starting with roughly 1l of leechant (I over shoot needs due to the fact that I prefer big batches).
Recovery will be carbon and I will be doing a ash out, water plunge separation then tossing the remains in the small furnace for a melt out. I should get a lil bead out of that.

More as it comes along.

--L

 

[nickvc]

I do not know if my input will help but you need to keep the solution heated, I think the temperature is fairly critical, and moving constantly to effectively strip the gold the same as using weak cyanide solutions, also from the little I understand of this method it will not load as much gold as cyanide so running a winning cell would allow the solution to be stripped of values and pumped back into the leach tank providing the movement, I'm not sure how the cell will react to the glycine so more may have to be added if it destroys some or all of it.
As I stated earlier this method has legs but the details at present are sketchy and I think testing is going to be needed to make the process work effectively, it also looks like this process will need specific equipment such as pumps to provide flow, a cell to strip the solution and almost certainly access to assaying to determine the effectiveness of the stripping and recovery, short version is this will not be for a hobbyist or home refiner until the process is proved.

 

[Barstool miner]

I have a very specific and unusual Gold coated Silica ore . I use the Simple Glycine hydrogen peroxide leach at +/- 150 deg F. . I still have to figure out how
to post photos. My pregnant leach has a reddish color to it giving me the impression of Colloidal Gold . I pass a red Laser beam thru the loaded leach and
get a clear line thru the leach , no defusion of the light . My Activated Carbon
increases by 16 grams per 1pound in my carbon column when I have dried the loaded AC . I am unable to elute the Gold from the Activated Carbon (AC )
I am able to recover the Gold by destroying the Glycine leach, turning it into
Chloride . I welcome new ideas

 

[FrugalRefiner]

I still have to figure out how to post photos.

See Attaching Images or Files, Working with Attachments.

Dave

 

[Barstool miner]

Thank you Frugal-refiner, for tips on posting pictures on this forum. I will have to study on it .

 

[FrugalRefiner]

You can practice in the Private message area.

Click on "Private message" up toward the upper right corner of the window.

Then click on "Compose message" from the menu list along the left side.

You can type a little text, attach a couple of images, and hit the "Preview" button to see how it looks. Play with the "Place inline" button.

The PM editing screen is pretty close to the Post editing screen. If you click on the "Submit" button by mistake, it will just give you an error that you didn't specify a subject or a recipient (don't ask me how I know ). I built a couple of my large projects that way.

Dave

 

[MareNextDoor]

Hi all,
Wanted to chime in here as I've been doing a lot of reading both on the forums and academic literature over the past few months and finally decided to register and contribute.
My background is a decade as an electrical engineer with a lifetime passion for chemistry, so I'm doing my best to use my career knowledge of the initial production process of what becomes ewaste to optimize my feedstock processing and selection.

I am still doing my "getting started" required reading and am abstaining from using strong acids until I know I have all safety measures in place. That being said, I decided to give alkaline glycine leaching a try since I'm comfortable with NaOH form prior soapmaking experience.

My feedstock is some trimmed PCI card and RAM stick fingers, as well as some trimmed down mylar flex PCBs from old cell phones that have what is likely ENIG gold on some of the ground planes.

I've been trying different ratios of H2O2 and glycine molarity (no more than 1M solution) along with constant stirring at room temperature, and I'm finding decent, albeit slow, success dissolving the base metals out from under the gold foils. I'm taking my time and waiting until I have more gold foils before I try a refining of the gold via higher temperature alkaline glycine process as outlined in literature.

I had an idea to use copper to drop out the other base metals in the waste glycine solutions and indeed immediately saw what I believe is nickel cement out on some pieces of copper plate placed in the copper glycinate filtrate. I'm hoping to figure out something to be able to drop out the copper in a way that preserves the glycine for reuse, though the only mention in literature I've found is sodium hydrosulfide, which I would prefer not to work with at this time. Perhaps there is a way to acidify the solution, use sodium metabisulfite to drop the copper, and then increase the pH again, without degradation of the solution.

Anyway, I've attached some photos, apologies for the quality, I took them simply for personal documentation at the time and wasn't expecting to post them.
That being said, I'm grateful for this place and how willing everyone is to share knowledge.

- Mare

 

[Yggdrasil]

Hi all,
Wanted to chime in here as I've been doing a lot of reading both on the forums and academic literature over the past few months and finally decided to register and contribute.
My background is a decade as an electrical engineer with a lifetime passion for chemistry, so I'm doing my best to use my career knowledge of the initial production process of what becomes ewaste to optimize my feedstock processing and selection.

I am still doing my "getting started" required reading and am abstaining from using strong acids until I know I have all safety measures in place. That being said, I decided to give alkaline glycine leaching a try since I'm comfortable with NaOH form prior soapmaking experience.

My feedstock is some trimmed PCI card and RAM stick fingers, as well as some trimmed down mylar flex PCBs from old cell phones that have what is likely ENIG gold on some of the ground planes.

I've been trying different ratios of H2O2 and glycine molarity (no more than 1M solution) along with constant stirring at room temperature, and I'm finding decent, albeit slow, success dissolving the base metals out from under the gold foils. I'm taking my time and waiting until I have more gold foils before I try a refining of the gold via higher temperature alkaline glycine process as outlined in literature.

I had an idea to use copper to drop out the other base metals in the waste glycine solutions and indeed immediately saw what I believe is nickel cement out on some pieces of copper plate placed in the copper glycinate filtrate. I'm hoping to figure out something to be able to drop out the copper in a way that preserves the glycine for reuse, though the only mention in literature I've found is sodium hydrosulfide, which I would prefer not to work with at this time. Perhaps there is a way to acidify the solution, use sodium metabisulfite to drop the copper, and then increase the pH again, without degradation of the solution.

Anyway, I've attached some photos, apologies for the quality, I took them simply for personal documentation at the time and wasn't expecting to post them.
That being said, I'm grateful for this place and how willing everyone is to share knowledge.

- Mare

Welcome

 

[Yggdrasil]

Hi all,
Wanted to chime in here as I've been doing a lot of reading both on the forums and academic literature over the past few months and finally decided to register and contribute.
My background is a decade as an electrical engineer with a lifetime passion for chemistry, so I'm doing my best to use my career knowledge of the initial production process of what becomes ewaste to optimize my feedstock processing and selection.

I am still doing my "getting started" required reading and am abstaining from using strong acids until I know I have all safety measures in place. That being said, I decided to give alkaline glycine leaching a try since I'm comfortable with NaOH form prior soapmaking experience.

My feedstock is some trimmed PCI card and RAM stick fingers, as well as some trimmed down mylar flex PCBs from old cell phones that have what is likely ENIG gold on some of the ground planes.

I've been trying different ratios of H2O2 and glycine molarity (no more than 1M solution) along with constant stirring at room temperature, and I'm finding decent, albeit slow, success dissolving the base metals out from under the gold foils. I'm taking my time and waiting until I have more gold foils before I try a refining of the gold via higher temperature alkaline glycine process as outlined in literature.

I had an idea to use copper to drop out the other base metals in the waste glycine solutions and indeed immediately saw what I believe is nickel cement out on some pieces of copper plate placed in the copper glycinate filtrate. I'm hoping to figure out something to be able to drop out the copper in a way that preserves the glycine for reuse, though the only mention in literature I've found is sodium hydrosulfide, which I would prefer not to work with at this time. Perhaps there is a way to acidify the solution, use sodium metabisulfite to drop the copper, and then increase the pH again, without degradation of the solution.

Anyway, I've attached some photos, apologies for the quality, I took them simply for personal documentation at the time and wasn't expecting to post them.
That being said, I'm grateful for this place and how willing everyone is to share knowledge.

- Mare

Copper will only drop the precious metals and Mercury if present.

 

[MareNextDoor]

Copper will only drop the precious metals and Mercury if present.

Ah right, I'll have to pull a piece and test the silver metal that's cemented onto the copper in that case.

 

[Yggdrasil]

Ah right, I'll have to pull a piece and test the silver metal that's cemented onto the copper in that case.

Silver will cement on Copper.