Iodine Leaching

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LeftyTheBandit

Well-known member
Joined
Aug 26, 2008
Messages
168
Location
Vancouver, British Columbia
Before I found this form I found an interesting web page from a basement chemist who liked to prospect and made his work available online in a very fun and colloquial manner.. His name was Dr. A.K. Williams, PhD.

I will share some of his insights on the use of Iodine to leach gold. I believe he has now passed away and his family keeps his web-sight going as a memorial. I in no way had any input into it's creation, although his simple process might be worth some discussion from some of our knowledgeable members and I hope posting his words is by no means breaking any rules of intellectual property. If so, please feel free to vaporize this topic.

Enough of my words... here is a paraphrase of what he had to say about Iodine Leaching;

"If you want to store iodine, it is much better to store it in its reduced form so that it won’t evaporate."

"...if you want to dissolve gold with it, it must be in its elemental or oxidized form."

"...you must be able to shift the iodine from its oxidized to reduced form."

"When you want your (iodine) in it’s elemental or oxidized form, simply add a little Clorox bleach. If you add an excess, Iodine will precipitate from the water solution and settle to the bottom as pure elemental, blue, iodine."

'If you want to dissolve the iodine, you must reduce it. This you can do by adding a little Red Devil Lye dissolved in water. The blue iodine will begin to go in solution so that the solution will first turn bright blue and upon addition of more Lye it will become colorless as all of the iodine is reduced to sodium iodide.'

'Elemental (oxidized) iodine will not dissolve in water. So if it won’t dissolve, how are we going to use it? It has another characteristic. It will dissolve in solutions of sodium iodide.'

'Now we have our ore with a nice red-brown solution of iodine and, hopefully, a whole bunch of dissolved gold in the solution. …... First we have to get rid of all the material that we have been extracting. This can be done in a number of ways but probably the most Basement way is to filter it… and try to get a rather clear solution. Remember that the solution must still be red-brown. If it isn’t, you have left your gold behind in the filter. .. KEEP IT RED-BROWN.'

'Once you have your red-brown solution free of material, now, you can let it go colorless or make it go colorless by addition of the Lye solution. Your gold will now slowly settle to the bottom as a black powder. Or, you can filter the solution through a fine filter to recover the gold.'

'… we got a whole bunch of gold but if we lose that iodine we are still going to be in the hole. Remember, at this point it don’t look like iodine but it is still there. By this time you probably have a pretty good volume of liquid with the iodine in it. If its more liquid than you want to deal with simply dump in an excess of Clorox , let the iodine settle to the bottom, pour off most of the water, add some Lye solution and you have your sodium iodide in a concentrated solution which is the way you want to store it anyway. Ready for another extraction.'



Could it be this simple? I'm going to try it... Instead of ore, I'm going to try eDust.
 
Just on the iodine method (Halides). Yes he was a great man. There are some small points missing on Halide Leaching. Not being a chemist it still sounded complicated but with the help of other Forum Members his writing on the subject then made sense and I am now able to use the suggested method. Still have to resolve how to smelt this. Just AR precipitations with SMB are simple as you use borax after cleaning for co precipitates etc.

From what I understand you dry and then boil your precipitates (gold iodide) in sodium hydroxide. It will convert this to a gold oxide. You then roast for a period of time to convert to metal. Then smelt.

Rainmaker back in April 2007 "Iodine Leach Procedures" gave an excellent example of recovery. Its worth looking at.

donnybrook
 
Do you require smelting, or melting? They are not the same thing.

It is my opinion that we should use terminology that is not confusing when discussing processes. There are those that take each and every word literally, and get the wrong message when improper terms are posted.

One smelts ores--------one melts recovered metals.

http://en.wikipedia.org/wiki/Smelting

Harold
 
I may be wrong, but I think the elemental form is the reduced form.

Jim
 
james122964 said:
I may be wrong, but I think the elemental form is the reduced form.

Jim

You are correct.

You can make up your etch solution by putting the Iodine crystals in a container and adding a small amount of Sodium Iodide solution in increments until the crystals dissolve. This will give you a red-brown 'Tincture.' Just add enough Sodium Iodide to do the job. It may take a while, so a stoppered container is best to keep from losing Iodine as a vapor. Give it a shake once in a while, or if you have it, a magnetic stirring bar and hot plate with stirrer to warm the solution and keep it circulating will speed things up greatly. Don't warm it too much as it will create pressure and possibly cause Iodine loss.

Another way to skin the cat here:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=5778

A great video.

Any Gold precipitated will need to be refined as other Elements will also precipitate. This is a recovery, not a refining technique.
 
Smelting or Melting.

Yes they are two different terms or processes. I melt my gold that has been precipitated with SMB after cleaning as it is very close to 24 carat or four nines gold.

Smelting is a different process used for the preparation of a lead dore for cupellation or you can undertake a dissolution of the button in weak nitric (must be weak) This in any case will only take up metals affected by nitric during the parting process. From memory the use of nitric can cause a coating on the dore. If either to strong or weak? There will still be lead residue there.

Before precipitating my PM's I always added a small amount of sulphuric to the boiled down AR which dropped any residual lead.

Smelting can help clean up a concentrate of metals containing copper. It is however destructive towards the crucibles and crucibles are not easy to acquire in Australia particularly the fire clay crucibles.

donnybrook
 
Could it be this simple? I'm going to try it... Instead of ore, I'm going to try eDust.[/quote]

Lefty, any development on e-dust? I'll try this process to, but with processors. English isnt my first language, so I have to ask some things, answers maybe obvious to you :oops:

I just bought 250 grams of 99% iodine crystal, equal amount of sodium hydroxide. If I get this right, first you mix NaOH with water, then you pure this on the iodine crystals. You get sodium iodide, where the iodine is safely stored.

So the right way now is to put processors in a container of some sort, adding sodium iodide and then clorox, that will turn the solution red-brown? And only this form-oxidized will strip the gold into iodine solution? And covering the container is important to trap the vapors? What do you think about putting this container in a cold place (fridge), would this reduce vapors or maybe stop the reaction with gold?

When working with HCL, there was always heat generated from the reaction. Is this the case with iodine?

Hope this isnt too much :shock: , all the best :lol:

Simon
 
dorki22 said:
Could it be this simple? I'm going to try it... Instead of ore, I'm going to try eDust.


Lefty, any development on e-dust? I'll try this process to, but with processors. English isnt my first language, so I have to ask some things, answers maybe obvious to you :oops:

I just bought 250 grams of 99% iodine crystal, equal amount of sodium hydroxide. If I get this right, first you mix NaOH with water, then you pure this on the iodine crystals. You get sodium iodide, where the iodine is safely stored.

So the right way now is to put processors in a container of some sort, adding sodium iodide and then clorox, that will turn the solution red-brown? And only this form-oxidized will strip the gold into iodine solution? And covering the container is important to trap the vapors? What do you think about putting this container in a cold place (fridge), would this reduce vapors or maybe stop the reaction with gold?

When working with HCL, there was always heat generated from the reaction. Is this the case with iodine?

Hope this isnt too much :shock: , all the best :lol:


Watch the video at this link:

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=48&t=5778

Keep your iodine concentration at 3-5 g/L

Simon[/quote]
 
Keep your iodine concentration at 3-5 g/L

Thanks for your advise Irons. What about NaOH, what concentration would you advise?

Today I started a test batch:
regular plastic (salat) container
1/2 liter tap water
15 grams NaOH (it looked way too much, have to get a ph indicator, now I cant tell, but I didnt want to trash my first home made lye)
3 grams Iodine crystal (I know:)
1pcs 486 CPU
0,5 dcl 20% H2O2 (also "feels" too strong)

After adding NaOH water looked a little less transparent, like when you add soap :), maybe little yellow. The crystals took about 20 minutes to get into solution. Then, when I added peroxide, solution turn to reddish milky kind, but still far from red. I supose, thats due to the excess NaOH.

After 1 hour no visable changes on the CPU, maybe little dark spots on few pins. Container has no agitation, and is closed. Will check for progress tomorrow morning.

Simon
 
dorki22 said:
Keep your iodine concentration at 3-5 g/L

Thanks for your advise Irons. What about NaOH, what concentration would you advise?

Today I started a test batch:
regular plastic (salat) container
1/2 liter tap water
15 grams NaOH (it looked way too much, have to get a ph indicator, now I cant tell, but I didnt want to trash my first home made lye)
3 grams Iodine crystal (I know:)
1pcs 486 CPU
0,5 dcl 20% H2O2 (also "feels" too strong)

After adding NaOH water looked a little less transparent, like when you add soap :), maybe little yellow. The crystals took about 20 minutes to get into solution. Then, when I added peroxide, solution turn to reddish milky kind, but still far from red. I supose, thats due to the excess NaOH.

After 1 hour no visable changes on the CPU, maybe little dark spots on few pins. Container has no agitation, and is closed. Will check for progress tomorrow morning.

Simon
Did you watch the video?

You have to make it acidic with HCL then add the oxidzer to release the Iodine.

You used way too much NaOH. You only need a fraction of a gram. Any more and you waste HCl making it active (acidic) again.

Next time start small. Use just enough water to cover the CPU and add a proportional amount of Iodine.

To precipitate the Gold, add small increments of NaOH solution until you see the black Gold powder precipitate.
 
james122964 said:
I may be wrong, but I think the elemental form is the reduced form.

Jim

Before someone gets on my case about this, it should be explained that Iodine in Potassium or Sodium Iodide has a charge of minus 1, so, technically, it is more reduced than the elemental form at a charge of 0.Iodine can exist at several oxidation potentials: 7, 5, 3, 1, and -1, 7 being the most oxidized and -1 being the most reduced. One must think of oxidation in terms of electron transfer. It can be a bit confusing, since the term 'oxidation', in this case, has nothing to do with Oxygen.
 
Did you watch the video?

You have to make it acidic with HCL then add the oxidzer to release the Iodine.

You used way too much NaOH. You only need a fraction of a gram. Any more and you waste HCl making it active (acidic) again.

Next time start small. Use just enough water to cover the CPU and add a proportional amount of Iodine.

To precipitate the Gold, add small increments of NaOH solution until you see the black Gold powder precipitate.[/quote]


Yuppi :p Thank you Irons very much. I know I blew it with some elements, but will try to make it right today afternoon.

Simon
 
This will be a good learning experience for you.

As Thomas Edison said : " I didn't fail 200 times to make a light bulb, I just learned 200 ways not to make one."
 
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
 
Irons said:
This will be a good learning experience for you.

As Thomas Edison said : " I didn't fail 200 times to make a light bulb, I just learned 200 ways not to make one."


Well, Im loving every minute of this. And I do appreciate, how you take time to help a complete stranger from unknown country god knows where, he he
Here is my second not to make it :p .

Todays menu:
2 dcl tap water
0,25 gram NaOH (still smells like too much)
0,6 gr iodine

Waited for about 2 hours, maybe 5% of crystals went in the solution.So I wondered, what the hell am I doing wrong? :idea: Yesterday I overdosed the solution with 2dcl of bleech. Today I just discarded the mix, poured fresh water and forgot to give my container a good clean. There was stil some oxidiser on the wall and top. Redoxing, and I mean literally :lol:
So I remembered your words about acidity, and added a few drops of muriatic. Solution emediatlly turned from slight yellow to brown. Well, there cant be too much of iodine in the solution, but enough to color the solution.

Had to put in the CPU, so I'll just wait now. Hope to see some changes.

Thanks again, Simon
 
Wyndham said:
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. :p

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.
 
Success 8) Well, a litlle one, but never the less...obvious discoloration of pins and lid. Hope its not just clorine messing with my experiment :oops:

I have a question,maybe a little silly one. Would it be reasonable lowering ph with (for example) white vinegar or something less corrosive than HCl? OK, vinegar also contains sugar and other stuff, but maybe other acidic, more "friendly to enviroment" cemicals :?:

Simon
 
dorki22 said:
Success 8) Well, a litlle one, but never the less...obvious discoloration of pins and lid. Hope its not just clorine messing with my experiment :oops:

I have a question,maybe a little silly one. Would it be reasonable lowering ph with (for example) white vinegar or something less corrosive than HCl? OK, vinegar also contains sugar and other stuff, but maybe other acidic, more "friendly to enviroment" cemicals :?:

Simon

The -Cl is needed to displace the Iodine in the Sodium Iodide. HCl is no big deal. At a pH of 5, it's about the same concentration as in your stomach. You only need enough HCl to make the solution turn red/brown. If it starts to get light, add a little more HCl. If that has no effect, you need to add more Iodine or H2O2. Baby steps.
Get some pH test paper.
 
I was looking on the net for an ORP meter and saw several that were $90-$120. portable shirt pocket types. Any idea how well these hold up in the environment were are talking about. I don't have the $$$$$ for some of the more expensive types. I try not to feed those that mine the miners, but like Irons says cheap can cost a lot more. Wyndham
 
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