Iodine leach

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kurtak said:
Just wanted to say thank you to everyone contributing to this thread :G 8) 8)

Its "really good" to see a discussion going on about a process different from the so to speak "norm" of processes discussed :mrgreen:

So thanks Pat for starting this thread - as well as the contributions of Rick, Yggdrasil, Owltech, etc. 8)

And Phil - Sooooo cool to see you pop in on this one --- reminds me of the good old days 8) :mrgreen:

Since my move I don't really do much any more - might just have to go looking for some material to play again :mrgreen:

Kurt
Come on in Kurt the water is fine...[emoji23][emoji1787][emoji16]

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I completely agree Rick.
We have nice comfortable water here :D
The only sharks we have here do not eat people anyway :mrgreen:
No pun intended Shark :wink:

Back to the topic, this is the kind of threads I really love.
When we combine forces and delve into the ocean of knowledge amongst our esteemed members and discover new/old things in new/old ways as a group.
The Iodine leach has been sitting in a hidden dusted down corner of my brain waiting to get out, since I first heard about it.

And then Pat opened this thread and the nuggets of knowledge just materialize :)
For me the main eyeopener was the patent document Owltech posted.
So I think the thanks should go to the ones that has done the testing, I'm just reading back my findings in the document.

In my eyes this is the kind of discussions that makes this forum so valuable.
Thanks to all the contributors, past and future.
If we can ignite enough interest to lure some of our dignified members back into the art again, even better :D :lol: :mrgreen:
 
Just wanted to say thank you to everyone contributing to this thread :G 8) 8)

Its "really good" to see a discussion going on about a process different from the so to speak "norm" of processes discussed :mrgreen:

So thanks Pat for starting this thread - as well as the contributions of Rick, Yggdrasil, Owltech, etc. 8)

And Phil - Sooooo cool to see you pop in on this one --- reminds me of the good old days 8) :mrgreen:

Since my move I don't really do much any more - might just have to go looking for some material to play again :mrgreen:

Kurt

Thanks indeed, to all!

In the last year and a half, I haven't done much processing either... I've been a bit burned out, so doing some resting; also recovering from a couple of surgeries to repair hernias, and my right knee.
I always like to check in, though,... and when I read about Pat's iodine testing, I said to myself, " I gotta try this"! :mrgreen:
 
I completely agree Rick.
We have nice comfortable water here :D
The only sharks we have here do not eat people anyway :mrgreen:
No pun intended Shark :wink:

Back to the topic, this is the kind of threads I really love.
When we combine forces and delve into the ocean of knowledge amongst our esteemed members and discover new/old things in new/old ways as a group.
The Iodine leach has been sitting in a hidden dusted down corner of my brain waiting to get out, since I first heard about it.

And then Pat opened this thread and the nuggets of knowledge just materialize :)
For me the main eyeopener was the patent document Owltech posted.
So I think the thanks should go to the ones that has done the testing, I'm just reading back my findings in the document.

In my eyes this is the kind of discussions that makes this forum so valuable.
Thanks to all the contributors, past and future.
If we can ignite enough interest to lure some of our dignified members back into the art again, even better :D :lol: :mrgreen:

I, for one, have been wanting to find an easier and safer way to de-plate gold... I've used the sulphuric cell successfully, but we all know its dangers... and it can be messy!
Pat's presentation made it look so safe, and simple, that I just needed to give it try.
So far, so good! Knock on :G :mrgreen:
I know that we'll all be able to end with a very detailed, and safe way to use this process!

This great Forum has the minds! 8) ... uhhhh, speaking of great minds, :)
I'm trying to rejuvenate the solution, but after adding about 20ml of peroxide, no change in color, other than when I add it.
So, my question is: after running 2.25 pounds of material thru the 300ml solution, the iodine was depleted? Can the solution be rejuvenated?
I've read that in some of the other tests, only a few items were deplated... maybe there was enough free iodine left, and that's the reason why it was rejuvenated!?

Thank you kindly!
 
philddreamer said:
I completely agree Rick.
We have nice comfortable water here :D
The only sharks we have here do not eat people anyway :mrgreen:
No pun intended Shark :wink:

Back to the topic, this is the kind of threads I really love.
When we combine forces and delve into the ocean of knowledge amongst our esteemed members and discover new/old things in new/old ways as a group.
The Iodine leach has been sitting in a hidden dusted down corner of my brain waiting to get out, since I first heard about it.

And then Pat opened this thread and the nuggets of knowledge just materialize :)
For me the main eyeopener was the patent document Owltech posted.
So I think the thanks should go to the ones that has done the testing, I'm just reading back my findings in the document.

In my eyes this is the kind of discussions that makes this forum so valuable.
Thanks to all the contributors, past and future.
If we can ignite enough interest to lure some of our dignified members back into the art again, even better :D [emoji38] :mrgreen:

I, for one, have been wanting to find an easier and safer way to de-plate gold... I've used the sulphuric cell successfully, but we all know its dangers... and it can be messy!
Pat's presentation made it look so safe, and simple, that I just needed to give it try.
So far, so good! Knock on :G :mrgreen:
I know that we'll all be able to end with a very detailed, and safe way to use this process!

This great Forum has the minds! 8) ... uhhhh, speaking of great minds, :)
I'm trying to rejuvenate the solution, but after adding about 20ml of peroxide, no change in color, other than when I add it.
So, my question is: after running 2.25 pounds of material thru the 300ml solution, the iodine was depleted? Can the solution be rejuvenated?
I've read that in some of the other tests, only a few items were deplated... maybe there was enough free iodine left, and that's the reason why it was rejuvenated!?

Thank you kindly!
When I rejuvenated mine I added 32% H202 drop wise. Each time I added it the solution would turn to a cloud of red as the drops entered the solution. I kept adding g slowly until it was back to it original color.

I added it faster on a second time and it was very vigorous to the point of almost "boiling" over the top of the beaker. It was a very hot reaction so I would use caution when adding the peroxide and use a catch basin.

The literature I read said you could recover the iodine by adding even more H202 and the filtering out the elemental iodine. (I have not tried this yet but it is on my to do list)

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Again pr the document and the forum:
It can be rejuvinated but it is recommended to not do it too many times.

Since the I2 - KI leach is acidic, it will pick up base metals which will make it less effective over time.
Just add 30% H2O2 slowly with stirring untill it have restored the deep brown color.

If you add 3% H2O2during the leach, it will leach significantly faster but it should be done at the bottom of the liquor so it will generate O2 bubbles through the liquor.
Which makes me think... How about an air pump like AP???

When it becomes too contaminated, you add 30% H2O2 with stirring untill all the Iodine has precipitated out.
It shall then be rinsed in HCl or Nitric and De Ionized water and it is ready to make up a new mix.

PS!
Rick beat me to it :lol:
 
Yggdrasil said:
Again pr the document and the forum:
It can be rejuvinated but it is recommended to not do it too many times.

Since the I2 - KI leach is acidic, it will pick up base metals which will make it less effective over time.
Just add 30% H2O2 slowly with stirring untill it have restored the deep brown color.

If you add 3% H2O2during the leach, it will leach significantly faster but it should be done at the bottom of the liquor so it will generate O2 bubbles through the liquor.
Which makes me think... How about an air pump like AP???

When it becomes too contaminated, you add 30% H2O2 with stirring untill all the Iodine has precipitated out.
It shall then be rinsed in HCl or Nitric and De Ionized water and it is ready to make up a new mix.

PS!
Rick beat me to it [emoji38]
The HCL wash is a new item for me. Thanks.

I also prepared a leach with just KI and HCL and added a small amount of 32% H202.

I used 50 grams KI and 50 ml of HCL in 250 ml DI water. (Distilled would work as well of course) I used 3 ml of H202.

It seemed to strip as well as using the elemental iodine and KI. I am concerned it may be more aggressive to base metals so I am going to do some trials of base metals only. I ordered some copper, nichol and carbon steel foils to test.

I will report here when I get the results.

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The HCl or Nitric wash is to clean the Iodine after it have been dropped out of the dirty Iodide solution.
The document uses the phrase "mineral acid" so I guess HCl might be the goto solution for most of us.

I'm going to test Ammonium Iodide because then I'm not confined to buy new KI.
I will then just generate the NH4I needed by adding NH4OH and H2O2 to the I2.
That is my plan at least :wink: :mrgreen:
 
rickzeien wrote:
The literature I read said you could recover the iodine by adding even more H202 and the filtering out the elemental iodine. (I have not tried this yet but it is on my to do list)
Well, I only have 12% H2O2, so I must have been too generous, and added extra H2O2, because the solution turned very brown and there're chunks of "something" floating, and at the bottom! :shock:
Is that my extra iodine that I'm supposed to filter out!?

Yggdrasil wrote:
If you add 3% H2O2during the leach, it will leach significantly faster but it should be done at the bottom of the liquor so it will generate O2 bubbles through the liquor.
Which makes me think... How about an air pump like AP???
In the old Iodine thread Gold-Digger seemed to find out that ,that's not a good idea!
https://goldrefiningforum.com/phpBB3/viewtopic.php?f=39&t=127&p=2701&hilit=Iodine+7%25+Leach+for+Gold#p3217

rickzeien wrote:
I also prepared a leach with just KI and HCL and added a small amount of 32% H202.

I used 50 grams KI and 50 ml of HCL in 250 ml DI water. (Distilled would work as well of course) I used 3 ml of H202.

It seemed to strip as well as using the elemental iodine and KI. I am concerned it may be more aggressive to base metals so I am going to do some trials of base metals only. I ordered some copper, nichol and carbon steel foils to test.

I will report here when I get the results.

yes, please keep us informed!

I'm going to test Ammonium Iodide because then I'm not confined to buy new KI.
I will then just generate the NH4I needed by adding NH4OH and H2O2 to the I2.
That is my plan at least :wink: :mrgreen:

I did a search on NH4I prices and they're 4 to 5 times more expensive! :?
For now, I'm sticking with KI :)

Gentlemen, thanks for your input!!!
 
I think so. Filter them and rinse. I believe elemental iodine is a blue/gray color.



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Iodide chrystal image
303344d198db8a2c8a5011f74bcf37ce.jpg


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Thanks everyone, I have been interested in this since owltech did his first videos of it. I have a growing pile of plated jewelry and hate to use the sulfuric cell right now due to other things keeping me busy. Maybe at a later date I can actually give it a try.
 
The quoting was a bit strange so I'm not sure whom to adress.
But anyway here it comes:
I did a search on NH4I prices and they're 4 to 5 times more expensive! :?
For now, I'm sticking with KI :)

From the document:
An aqueous solution containing 400 gms of ammonium iodide was prepared as follows:
(1) 500 ml of de-ionized water was placed in a 2-liter beaker.
(2) 351 gms of iodine were added.
(3) 47 gms of hydrogen peroxide were added and stirred.
(4) 97 gms of ammonium hydroxide were slowly added and stirred until all the iodine dissolved.
(5) 100 gms of supplemental iodine were added and stirred until the deep dark brown solution formed and all the iodine had dissolved.
(6) The dark brown solution was then diluted to 1 liter.

Experiment 2
A 200-ml aliquot of the 1-liter etching solution was transferred to a 400 ml beaker. Several small parts,
plated with 20-30 micro-inches of gold were immersed in the etching solution at room temperature, for 5 min utes.
Small amounts of hydrogen peroxide were intermittently fed dropwise into the bottom of the beaker containing the etching solution,
so as to form a slow and steady stream of oxygen bubbles rising to the surface of the etching solution.
The parts were then removed and rinsed. All the gold plate had dissolved off within 5 minutes at room temperature and the remaining base metal was left bright and only slightly etched.
The dissolved gold was precipitated out of the etching solution by adding, slowly and with stirring, crystals of sodium meta-bisulfite,
until the deep dark brown etching solution changed to a light yellow color.
A fine gold precipitate settled out within 30 minutes and was filtered off.
The filtrate was then oxidized by adjusting the pH to about 6 with sodium bicarbonate and then slowly adding 30% hydrogen peroxide with stirring.
The solution color changed from light yellow to deep dark brown.
A second collection of similarly gold plated small parts was immersed in the restored etching solution for 5 minutes.
Again, all the gold plate dissolved off within 5 minutes and was then precipitated out with sodium meta-bisulfite.
The gold precipitate was then filtered off. During the second reduction operation the color of the etching solution again went from dark brown to light yellow.
This time the clear light yellow filtrate was acidified, pH 2-3, with hydrochloric acid.
A 30% solution of hydrogen peroxide was slowly added, with stirring, to the acidified filtrate.
All the iodine in the ammonium iodide-iodine etching solution was precipitated out as elemental iodine.
It was filtered off and washed sequentially with
1) de-ionized water,
2) dilute hydrochloric acid, and
3) de-ionized water. The elemental iodine was now available for making up a new ammonium iodide, iodine etching solution.

Specifically this:
(3) 47 gms of hydrogen peroxide were added and stirred.
(4) 97 gms of ammonium hydroxide were slowly added and stirred until all the iodine dissolved.

So one do not have to buy Ammonium Iodide if one has access to 30% H2O2, which one should have anyway, when running an Iodine- Iodide leach.
 
Is the percentage of ammonium hydroxide specified?

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Rick.
So far I haven't found any reference to the strength.
The ammonium iodide is prepared by adding elemental iodine to water, then adding 30% hydrogen peroxide and finally adding slowly, and with stirring, a solution of ammonium hydroxide.
Iodine is barely soluble and barely reacts with an aqueous solution of ammonium hydroxide. However, it readily dissolves in and reacts with the ammonium hydroxide when hydrogen peroxide is present.
The ammonium iodide that forms is readily soluble in the aqueous solution.
So since it was referenced as an aqueous ammonium hydroxide I kind of assumed it to be sufficient with 15% household brand.
But then again assumptions is the mother of all f... .ps.

Here is the link Owltech posted:

Re: Iodine leach

Post by Owltech » June 27th, 2020, 5:19 am

patnor1011 wrote: ↑
June 25th, 2020, 7:28 pm

Owltech wrote: ↑
June 18th, 2020, 11:39 am
SMB can be used too

Will SMB or ascorbic drop also silver from solution or something else is used to drop silver?

https://patentimages.storage.googleapis ... 137700.pdf
 
I have found that after I drop gold from first iodine-iodide solution and rejuvenated it I left it to stand in a closed bottle - it developed some white/yellow/gray crust towards the bottom of the bottle. I decanted iodine solution to another bottle and kept this crust-crystals in bottle where they formed.

I used this rejuvenated iodine solution to deplate gold and found that it is not as fast as the original solution, I need to find out why.

I am thinking that I will try to extract iodine after every use and make a fresh leach solution every time. According to patent owltech posted 1l of this leach should hold up to an ounce of gold. Extracting iodine and making iodide from some of it to create fresh leach every time is more time consuming than simply rejuvenating, I need to play with this some more to figure out what may be the best solution.
 
Pat
I believe the crust is precipitated/crystallized base metal salts and the reduced efficiency of the leach are caused by increasing amount of base metals in the solution.
 

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