Iodine leach

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Re: Iodine leach

Post by rickzeien » July 5th, 2020, 12:09 pm

kurtak wrote: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...ImageImageImage

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Re: Iodine leach

Post by Yggdrasil » July 5th, 2020, 1:17 pm

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:
Best Regards PoA

My Primary language are not English so language errors may occur, please do correct me whenever needed :-)

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Re: Iodine leach

Post by philddreamer » July 5th, 2020, 3:27 pm

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:
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You may say that I'm a dreamer... but I'm not the only one!
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The difference between a dream & reality is, a good plan!
WARNING: No "cartridge type" respirator will filter out nitric fumes, NONE!!!

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Re: Iodine leach

Post by Yggdrasil » July 5th, 2020, 3:36 pm

Just what I said, another bonus on top of the icing of the cake :D :D :mrgreen:
Best Regards PoA

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Re: Iodine leach

Post by philddreamer » July 5th, 2020, 3:52 pm

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!
If you are going to dream... DREAM BIG!!!
You may say that I'm a dreamer... but I'm not the only one!
"Paper money eventually returns to its intrinsic value --- zero." Voltaire (1694-1778)
The difference between a dream & reality is, a good plan!
WARNING: No "cartridge type" respirator will filter out nitric fumes, NONE!!!

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Re: Iodine leach

Post by rickzeien » July 5th, 2020, 4:18 pm

philddreamer wrote:
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 Image :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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Re: Iodine leach

Post by Yggdrasil » July 5th, 2020, 4:22 pm

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:
Best Regards PoA

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Re: Iodine leach

Post by rickzeien » July 5th, 2020, 4:32 pm

Yggdrasil wrote: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 Image
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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Re: Iodine leach

Post by Yggdrasil » July 5th, 2020, 5:29 pm

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:
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Re: Iodine leach

Post by philddreamer » July 5th, 2020, 6:49 pm

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!
viewtopic.php?f=39&t=127&p=2701&hilit=I ... 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!!!
If you are going to dream... DREAM BIG!!!
You may say that I'm a dreamer... but I'm not the only one!
"Paper money eventually returns to its intrinsic value --- zero." Voltaire (1694-1778)
The difference between a dream & reality is, a good plan!
WARNING: No "cartridge type" respirator will filter out nitric fumes, NONE!!!

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Re: Iodine leach

Post by rickzeien » July 5th, 2020, 7:54 pm

I think so. Filter them and rinse. I believe elemental iodine is a blue/gray color.



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Re: Iodine leach

Post by rickzeien » July 5th, 2020, 8:01 pm

Iodide chrystal image[IMG]//uploads.tapatalk-cdn.com/202007 ... cf37ce.jpg[/IMG]

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Re: Iodine leach

Post by Shark » July 5th, 2020, 9:50 pm

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.
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Re: Iodine leach

Post by Yggdrasil » July 6th, 2020, 2:48 am

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.
Best Regards PoA

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Re: Iodine leach

Post by rickzeien » July 6th, 2020, 4:36 am

Is the percentage of ammonium hydroxide specified?

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Re: Iodine leach

Post by Yggdrasil » July 6th, 2020, 4:49 am

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
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Re: Iodine leach

Post by rickzeien » July 6th, 2020, 4:51 am

Thanks

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Re: Iodine leach

Post by patnor1011 » July 6th, 2020, 10:17 pm

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.
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Re: Iodine leach

Post by Owltech » July 7th, 2020, 2:44 am

"Alchemists turned into chemists when they stopped keeping secrets"
Eric Raymond

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Re: Iodine leach

Post by Yggdrasil » July 7th, 2020, 3:01 am

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.
Best Regards PoA

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Re: Iodine leach

Post by kurtak » July 7th, 2020, 10:13 am

rickzeien wrote:
July 5th, 2020, 12:09 pm
Come on in Kurt the water is fine...ImageImageImage

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:lol: :lol: :lol:

Thanks for the encouragement - but the problem is not jumping in to give it a go - the problem is not having material to jump in on

When I made my move I brought a trailer load of higher grade material with me & last year I went through the trailer & pulled out the vast majority of the plated stuff & processed it - got 52 grams out of that run - if I dug "deep" back into the trailer I "might" come up with another pound of plated material - just not worth chasing for a gram or two

Where I now live there just is not a lot of material available because grant county (which is like the 4th or 5th largest county in Oregon) only has about 7,500 people in the county (there is only one stop light in the whole county) so finding scrap is hard to even find - the county is like 70 - 80 % national forest

I do have like 60 - 70 pounds IC chip I hope to process this year but that's an incinerate/smelt process

As well I have a few hundred pounds of HIGH chip pop boards - but again - those are an incinerate/smelt process

Also have a few hundred pound of some "good" silver recovery stuff (contact points)

Just don't really have any (or much) gold plated to play with :( - or I would certainly jump in to play :mrgreen:

That all said - I sure am enjoying watching you all play :G :mrgreen:

Kurt

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Re: Iodine leach

Post by patnor1011 » July 7th, 2020, 8:21 pm

I wonder (and will try this) if this is not a way to get silver out of keyboard mylar sheets. I have saved up about 15 kilogram of them. Seems like a next project but I will have to find a way to get hydroxylamine :)
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Re: Iodine leach

Post by patnor1011 » July 7th, 2020, 8:23 pm

Yggdrasil wrote:
July 7th, 2020, 3:01 am
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.
That is what I thought so that is why I think that I will remove iodine and start fresh after every use, or every other one.
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Re: Iodine leach

Post by philddreamer » July 12th, 2020, 7:13 pm

I finally had some time today and melted a .2g buttom... :( … I think I dissolved more base metals than gold. So, I've been doing some reading and I found this:
https://www.sciencedirect.com/science/a ... 6X9190029L
which reads:
Several oxidants (hypochlorite, iodine and hydrogen peroxide) were used to evaluate the dissolution of gold in iodide electrolytes at ambient temperatures. Evans diagrams constructed for the two half cells involved in the dissolution process show that hydrogen peroxide is not a suitable oxidant for the iodide system.
The gold dissolution rate in an iodine-iodide mixture is dependent upon the concentration of iodide, iodine and the solution pH. An optimum iodine-iodide mole ratio of 0.35–0.4 was found for 0.1 M KI solutions, with pH ranging from 2.7 to 11.5; these are capable of dissolving gold at a maximum rate of 17 mg/cm2h.
If a small addition of hypochlorite is made (< mM for 0.1 M KI solutions), gold will be dissolved faster than with iodine as oxidant. However, the gold dissolution rate in a hypochlorite-iodide mixture is strongly dependent upon the solution pH. The optimum hypochlorite-iodide mole ratio is 0.25 for KI solutions of 0.02 to 0.1 M at pH 2.7.
Cyanidation, using the same concentration of cyanide yielded gold dissolution rates within the range of 1.3 (at pH 12.5) and 3.5 mg/cm2h (at pH 8.5).
I'll make another batch and check the pH, and maybe bring it to pH6 (or higher) if need be!?
Maybe then, it will dissolve more gold and less base metals!?
Just wondering... :|

Thank you!
Phil
If you are going to dream... DREAM BIG!!!
You may say that I'm a dreamer... but I'm not the only one!
"Paper money eventually returns to its intrinsic value --- zero." Voltaire (1694-1778)
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WARNING: No "cartridge type" respirator will filter out nitric fumes, NONE!!!

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patnor1011
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Re: Iodine leach

Post by patnor1011 » July 13th, 2020, 12:33 am

Key here may be in using uniform stock. Like if the material is the same it is easy to observe when gold is dissolved and material can be removed before any significant amount of base metals start dissolving. Also agitation. When I did it I used smaller amount of material going up and down in solution. THat way it was all exposed more or less equally.
I would love to try like 5l of solution in a RVEC. :mrgreen:
What you see isn't all there is. And what you assume, hardly ever is.

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Re: Iodine leach

Post by philddreamer » July 13th, 2020, 9:14 pm

patnor wrote:
Key here may be in using uniform stock.
I just started doing that last night... :P while looking for more material to process, I came across 11 pounds of the same material, so I've been sorting it, and prioritizing... which one will be processed first and so on!
I still would like to know, though, that if by adding some lye and bringing up the pH, if that would help keep base metals from dissolving too readily... :|

phil
If you are going to dream... DREAM BIG!!!
You may say that I'm a dreamer... but I'm not the only one!
"Paper money eventually returns to its intrinsic value --- zero." Voltaire (1694-1778)
The difference between a dream & reality is, a good plan!
WARNING: No "cartridge type" respirator will filter out nitric fumes, NONE!!!

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patnor1011
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Re: Iodine leach

Post by patnor1011 » July 15th, 2020, 8:24 am

Don't know Phil all we can do is to try :)
I picked up 50 laptops so when I tear them apart I will have some more material to experiment with.
What you see isn't all there is. And what you assume, hardly ever is.

It ain't what you don't know that gets you into trouble. It's what you know for sure that just ain't so.

Gold inside chips (black, flatpacks - not CPU) - http://www.goldrefiningforum.com/phpBB3 ... 52&t=11827

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Re: Iodine leach

Post by philddreamer » July 21st, 2020, 6:31 pm

Well, here's an update on my iodine leach process...
I made a new batch, I checked the pH = 6.7; so I added 2 pounds of low yield plated material, and it de-plated quickly; I decanted the solution and added another 2 pounds. As I swished the solution, the solution quickly became clear!!! :shock:
So... I thought, that means I de-pleated the iodine!?
So I added some 12% peroxide, and the iodine color came back, BUT, that's when things went BLAHHH! :?
The solution started to foam up, so I added a bit of water, proceeded to decant the solution and add some SMB in order to drop the gold.
The gold didn't drop, but the base metals did, resembling silver chloride, (though no silver was in material). :roll:
I suspected that the gold cemented, so I inspected the left over material and it seems so.
I need to go back to the drawing board, sit down and evaluate things... :mrgreen:

Pat mentioned about the thio cell, is it this one?
viewtopic.php?f=86&t=28686#p302362

phil
If you are going to dream... DREAM BIG!!!
You may say that I'm a dreamer... but I'm not the only one!
"Paper money eventually returns to its intrinsic value --- zero." Voltaire (1694-1778)
The difference between a dream & reality is, a good plan!
WARNING: No "cartridge type" respirator will filter out nitric fumes, NONE!!!

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Re: Iodine leach

Post by nickvc » July 22nd, 2020, 3:26 am

Phil what you experienced is very similar to what happens if you overload a cyanide solution which is very easy with plated materials as the leach prefers copper and nickel, so you strip the gold and it cements back out as it prefers to dissolve them, weak solutions are much more selective but also more time consuming and produces much more waste solutions.
I think you are going to have to play with your solution and different ph levels to find the optimum balance, I remember talking to our much missed GSP about this and also recall him saying he made good money buying other refiners stripped material and doing the job properly :o

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Re: Iodine leach

Post by philddreamer » July 22nd, 2020, 9:08 pm

Nick wrote:
Phil what you experienced is very similar to what happens if you overload a cyanide solution which is very easy with plated materials as the leach prefers copper and nickel, so you strip the gold and it cements back out as it prefers to dissolve them, weak solutions are much more selective but also more time consuming and produces much more waste solutions.
I think you are going to have to play with your solution and different ph levels to find the optimum balance, I remember talking to our much missed GSP about this and also recall him saying he made good money buying other refiners stripped material and doing the job properly :o
Thanks, Nick!
Yes, I'm afraid I have overloaded the solution... :oops: It's obvious that we need to find a balance.
I have been thinking of diluting and/or raising the pH levels, then run some tests until we figure it.
Yeap, I miss Chris, too! :cry:

I will be trying the thiourea/citric cell soon... lets see how that works out with big batches!!!
I know, I know... "we donee no stinking baachess!" :mrgreen:

phil
If you are going to dream... DREAM BIG!!!
You may say that I'm a dreamer... but I'm not the only one!
"Paper money eventually returns to its intrinsic value --- zero." Voltaire (1694-1778)
The difference between a dream & reality is, a good plan!
WARNING: No "cartridge type" respirator will filter out nitric fumes, NONE!!!

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