Iodine Leaching

[dorki22]

This will be a good learning experience for you.

Irons, I am a bit stranded.
You were talking about 7gr/liter of iodine crystals in water+NaOH

I've noticed patents talking about mixing 4 parts of potassium iodide with 1 part iodine crystal.

Question:
Is the 7gr/liter equal to 4 parts of KI or is this allready the desired leaching solution?

Simon

 

[Irons]

The KOH is used to initially convert Iodine to KI and Potassium Iodate.
KI can then be used to dissolve more iodine to make up the etching solution in the 3-5 g. per liter of Iodine and adjusted to pH 4-5 with HCl.

I don't know where you came up with 7 g. per liter but that would work as well.

There are a number of variations of formulation, some acidic, some basic. It can get very confusing to sort them out.

The main feature of using Iodine is that it can be selective for Gold, but only if you keep the reaction parameters within limits, otherwise, other metals begin to be dissolve, defeating the purpose of the process.
I suggest purchasing a combination pH and ORP (Oxidation Reduction Potential) meter and use that to monitor the reaction.

 

[dorki22]

The KOH is used to initially convert Iodine to KI and Potassium Iodate.
KI can then be used to dissolve more iodine to make up the etching solution in the 3-5 g. per liter of Iodine and adjusted to pH 4-5 with HCl.

I don't know where you came up with 7 g. per liter but that would work as well.

There are a number of variations of formulation, some acidic, some basic. It can get very confusing to sort them out.

The main feature of using Iodine is that it can be selective for Gold, but only if you keep the reaction parameters within limits, otherwise, other metals begin to be dissolve, defeating the purpose of the process.
I suggest purchasing a combination pH and ORP (Oxidation Reduction Potential) meter and use that to monitor the reaction.

Thanks Irons, the 7 - my mistype , I know you wrote 3-5 g/l

I'll have to learn some more, while waiting for my ph meter (ORP maybe next month), because iodine, iodide and iodate looks like some hard chemistry :lol:

Simon

EDIT: Does the ph4-5 work also for platinum?

 

[Irons]

The KOH is used to initially convert Iodine to KI and Potassium Iodate.
KI can then be used to dissolve more iodine to make up the etching solution in the 3-5 g. per liter of Iodine and adjusted to pH 4-5 with HCl.

I don't know where you came up with 7 g. per liter but that would work as well.

There are a number of variations of formulation, some acidic, some basic. It can get very confusing to sort them out.

The main feature of using Iodine is that it can be selective for Gold, but only if you keep the reaction parameters within limits, otherwise, other metals begin to be dissolve, defeating the purpose of the process.
I suggest purchasing a combination pH and ORP (Oxidation Reduction Potential) meter and use that to monitor the reaction.

Thanks Irons, the 7 - my mistype , I know you wrote 3-5 g/l

I'll have to learn some more, while waiting for my ph meter (ORP maybe next month), because iodine, iodide and iodate looks like some hard chemistry :lol:




Simon

EDIT: Does the ph4-5 work also for platinum?

Once you get the gold stripped off the outside of the CPUs, you can leach them in dilute HCl with a little H2O2 to dissolve the base metals. Then you can go for the rest of the Gold.

I have not tried it with Pt, but according to literature, it will work, perhaps at a higher oxidation potential.

I recently purchased a combination pH/ ORP controller to automate the strip process. It was about $140 US, airmail from Hong Kong.

 

[Palladium]

I recently purchased a combination pH/ ORP controller to automate the strip process. It was about $140 US, airmail from Hong Kong.

A controler ?

You got a link or tech. sheet on it Irons ?

 

[Irons]

I recently purchased a combination pH/ ORP controller to automate the strip process. It was about $140 US, airmail from Hong Kong.

A controler ?

You got a link or tech. sheet on it Irons ?

I figured it would get your attention. :mrgreen:

http://tinyurl.com/yj8ymxy

They have versions for 110 or 220 mains input. This is the US version. It's ac only powered and the displays ar LED so they can be easily seen in a dimly lit shop. The plugs are universal. They will accept US and EU type AC connectors. The unit I received had both outlets in a single module.
They also carry replacement electrodes at a reasonable price.
It's ruggedly built.
This outfit has a lot of neat items.

 

[DNIndustry]

there are several patents that work well. the nh4i version is the most effective and the best controlled. uses a buffer and an accelerator.

 

[dorki22]

there are several patents that work well. the nh4i version is the most effective and the best controlled. uses a buffer and an accelerator.

It would be very nice, if you could post some links for this particular patent. Could this be your patent?

Greetings
Simon

 

[lazylightning]

Hi!

I'm trying to do an iodine leach and I've encountered an interesting problem. I made the leach solution, a liter with about 5 grams of iodine in it. That was easy. The solution was darker than dark beer, no way to see through it at all, dark brown very dark. I added it to the leach and stirred by hand for a while, let it sit and then added it into a mixer with eight propellor balde with a diameter about as wide as the inside of the reactor. After two hours of stirring at about 450 rpm's, I took it out and filtered. The solution is lightly tan. So where did all of my iodine go? I made up some more potassium iodide solution/concentrated and added to the filtered ore in hopes that it would dissolve any iodine that had precipitated. No good, the iodine is stuck somewhere. So you see what some good stirring is good for ;-)

Any ideas?

 

[Irons]

Hi!

I'm trying to do an iodine leach and I've encountered an interesting problem. I made the leach solution, a liter with about 5 grams of iodine in it. That was easy. The solution was darker than dark beer, no way to see through it at all, dark brown very dark. I added it to the leach and stirred by hand for a while, let it sit and then added it into a mixer with eight propellor balde with a diameter about as wide as the inside of the reactor. After two hours of stirring at about 450 rpm's, I took it out and filtered. The solution is lightly tan. So where did all of my iodine go? I made up some more potassium iodide solution/concentrated and added to the filtered ore in hopes that it would dissolve any iodine that had precipitated. No good, the iodine is stuck somewhere. So you see what some good stirring is good for ;-)

Any ideas?

The Iodine reacted with the Gold. The Gold Iodide is not very soluble. Add some KI, which should cause it to go into solution, where it can be precipitated with KOH.

 

[lazylightning]

Hi!

I'm trying to do an iodine leach and I've encountered an interesting problem. I made the leach solution, a liter with about 5 grams of iodine in it. That was easy. The solution was darker than dark beer, no way to see through it at all, dark brown very dark. I added it to the leach and stirred by hand for a while, let it sit and then added it into a mixer with eight propellor balde with a diameter about as wide as the inside of the reactor. After two hours of stirring at about 450 rpm's, I took it out and filtered. The solution is lightly tan. So where did all of my iodine go? I made up some more potassium iodide solution/concentrated and added to the filtered ore in hopes that it would dissolve any iodine that had precipitated. No good, the iodine is stuck somewhere. So you see what some good stirring is good for ;-)

Any ideas?

The Iodine reacted with the Gold. The Gold Iodide is not very soluble. Add some KI, which should cause it to go into solution, where it can be precipitated with KOH.

Thanks! I'll give it a try! I was planning to do that just in case, but your explaination gives me more confidence with an idea of why and exactly what I'm trying to do =-)

 

[solar_plasma]

Irons,I'm a bit slow on the uptake so I wanted to ask you in a way of what i have. If I have the pins,cpu's etc in a container and I add enough water to cover the material then add the same amt of Provodine or betadine then add enough hcl to make it a bit? acid(what ph) After a time, add lye to drop the gold out of solution(till the solution clears??) filter and then melt or have i branched to the wrong direction.
If above is correct or be corrected, what do I add to regenerate the iodine solution.
I'm not that well versed in the steps since there have been several different description of this method and am a bit confused because some seem to start with elemental iodine and others with a solution of 9% iodine.
Thanks for any help
BTW have the snows hit the high country out your way yet? Wyndham

It's cold and wet at home but we're on the beach in Florida at the moment.

The pH should be at 4-5 during leaching. If your pH gets too low, it will begin to leach Iron.

If you have an ORP meter, keep the potential between 400 and 900 mV. Above 900 mV, the Iron will leach.

You can precipitate the Gold with popular reducing agents such as SO2 or SMB. After the Gold precipitates, filter it, saving the liquid, which can be regenerated using HCl and H2O2.

Like any process, results will vary.

What will happen under 400 mV? Will it stop leaching gold?
How can I find out or calculate, at how many mV other metals will dissolve?
Will that mean, that at a little over 400 mV it is most selective to gold?

I'm very interested in that, because my ORP-electrode has been delivered. Just waiting for the adapter.

 

[lgjonbalaj]

Can anyone shed some light as to how I can remove iodine staining from my gold jewelry? :shock:

 

[jimdoc]

Can anyone shed some light as to how I can remove iodine staining from my gold jewelry? :shock:

https://www.reddit.com/r/askscience/comments/24q99b/chemists_i_ruined_metal_jewelry_when_i_spilled/

 

[ashir]

i have elemental iodine, 100 g
i want use it to leach gold from clean mobile boards. can any one suggest a mathod to prepare a solution to leach gold???
i need a complete step by step process,
as many posts are as keeping top secrets!
anyone that can post complete process from solution preparing to percipitate gold and recover iodine to re use!

 

[Lino1406]

100g iodine will require 65.4g potassium iodide. Water - make a saturated KI solution, then mix with iodine

 

[ashir]

what if i use iodine tincture? that look cheap if it works? sodium iodide is not avail on shops near me, hoing yo order it!
i can buy 1 liter iodine tincture in 10 dollars!

 

[Platdigger]

If I remember right, that tincture is only like 10 or so % iodine.

 

[ashir]

If I remember right, that tincture is only like 10 or so % iodine.

yes its not more than 15 percent!
i am looking areceipe that works with simplest form of iodine leach, maight be prepared with other cheap ingredient with iodine!

 

[DNIndustry]

I have done a literal ton of iodine refining. Elemental iodine and ammonium iodide is the most controlled method. KI rips the shit out of underlying base metals. The ammonium version gets Pd, Gold and seems to stop at any nickel base layer.