# Iodine 7% Leach for Gold



## Gold-Digger

Has anyone here tried using Strong Iodine Tincture 7% for leaching of gold?? I'm investigating this technique and it appears to be sound but slow and more expensive..


----------



## Noxx

No, I never tried this technique. Please share what you've found.


----------



## lazersteve

I've heard of it. Chlorine will do the same job and it's more readily available. Please share what you have found.


----------



## shadybear

I have read about it but never tried to use it yet, but the info looks great. I read it is highly selective for gold, But slow.
And I read somewhere it could be used with dbg as well.
I think it is much more expensive than other methods in upfront costs but it is re-useable so in the long run may be equal to or cheaper than other methods.
I saw it in the feed store last time I was there, some kind of hoof treatment, about 8.99 a pint.


----------



## Gold-Digger

Here's my first iodine strip. I put in about 2 ounces of material. Hopefully the picture posts o.k. and you can see what the material looked before and after. Most of this was from memory sticks. So small pieces but then again I'm practicing. 

I let this go overnight versus waiting a day or two but I just wanted to see if it was working or not. So there remains a couple small specks of gold still left on the fingers but most appears to be stripped clean. Hurray!!! 

I made two batches of this and the other I put in various CPU's like Pentium and AMD. What I noticed is some of these parts seems to be stripping great but others appear to be stripping much slower. I wonder why? Any ideas?

I am playing with this technique and if anyone is using this PLEASE let me know. I could use some help..


----------



## lazersteve

Gold-Digger,

Are you getting gold flakes in your solution or have you tested the liquid to see if it has Au dissolved in it? 


I'm wondering if the purple color you see is residual iodine or colloidal gold (most probably the iodine). If you want you could take some rubbing alcohol and rinse the fingers that you have 'stripped' to see if the gold shows back thru the purple. You may not have removed anything, you may have just discolored the gold foil. Can you confirm the gold has been removed into solution? If it has you may be onto something if you can get past the messy nature of iodine. Another problem will be the testing of the solution as iodine gives a purple color in solution. Keep us posted.

Nice work.

Steve


----------



## lazersteve

Gold-Digger,

Here's a link that will get you started on getting your gold back from solution if you have succeeded in stripping the gold:

http://patft.uspto.gov/netacgi/nph-...50&s1=4319923.PN.&OS=PN/4319923&RS=PN/4319923

Looks like you can recycle your iodine solution too!

Steve


----------



## Gold-Digger

I put in a couple CPU's in a different Iodine solution and a lot of the pins dropped out and are now resting on the bottom of the container. Plus they are almost black colored. I also wiped down a few areas of these memory stick end fingers with alcohol and no colored returned.

What has me baffled is some of the pins still look nice and gold colored almost like nothing has happened. While others on the same CPU other pins are completely wiped clean of any gold. Very weird but guessing that maybe these pins have a lot more gold on them or somehow an oxide got built up around a few of them during the etch process... but weird!

I know I'm suppose to use a stirring method to keep the solution moving around and perhaps it creates small pools of leaching solution while other areas end up void within the bath.. I have a small aquarium air pump which I was told would keep the solution moving. Maybe that's the key to this funny etch pattern? But in an acid solution?????????


----------



## lazersteve

Gold-Digger,

The air bubbles may be protecting some areas of the gold with air. The air is possibly displacing the etchant and therefore creates odd etch patterns. You should try agitation with some sort of vibrating motor or something similar. 

Did you check out the article link I posted?

Steve


----------



## NaNO3

Gold-Digger

Iodine leach goes to work immediately on Gold, then Platinums, then Silver, in that 
order. It tends to ignore the other "Trash" metals. Naturally, it is about PH 4-5, 
and is kept there, especially in the presence of Alkali metals, by adding small amounts of HCL acid.
Typically 24-48 hours to collect fine gold.
The leach will only stop working when the PH rises to 7.
Mix everything together in your container, making sure you have fresh air circulation, as confined
Iodine fumes can be toxic, and burn your eyes. For agitation, you can add a small air bubbler with 
stone at the bottom of the leach tank, like
those used in aquariums, to keep the mixture circulating.


----------



## lazersteve

Will potassium iodide in water work the same or do you need some free iodine in the mix? Got info on ratios, percentages, weights, volumes, etc.?


----------



## NaNO3

> Will potassium iodide in water work the same or do you need some free iodine in the mix?



I used "Lugol’s Iodine". This is simply Iodine dissolved in a solution of Sodium Iodide.



> Got info on ratios, percentages, weights, volumes, etc.?


Ill have to dig up my notes on it.


Gold-Digger

To get your gold out of your Iodine solution add some NaOH and the
solution will go colorless.
Your gold will now slowly settle to the bottom as a black powder.


----------



## lazersteve

Here are some ratios I came up with from a University Document :

4g:2g:10ml - KI:I2:H2O Hot (70C) 280 nm/min 


Steve


----------



## Gold-Digger

O.K. this answers a lot of questions. THANKS!!!

Sorry but more questions...

1. Are you using any type of precipitant such as Zinc or anything like that when you use lye to a Ph of 6 or 7? I have a compound I purchased specifically for this process but probably not the right place to list this. I can email you the info if you want it..
2. Are you watching the ORP? And a dumb question but what chemical are you using to control the ORP (it is a factor of the HCl to H2O or Iodine to Water, etc?).. I was told to check this and ensure it never goes above 900 otherwise it will start leaching iron but not sure how to control ORP readings.

After it settles then you filter and dry are you:

1. Firing with a Flux as described by C.W. Ammen (Recovery and Refining of Precious Metals, 2nd edition) at around 2000 degrees F (1100 C)? The flux he describes is sodium carbonate, lead monoxide, silica (sand), Borax, wheat flour, etc..... 
2. Are you buying a pre-made flux from someone such as Action Mining?
3. Are you just using Borax and ash?

I currently have a pre-made flux plus I have a box of Borax. From what I understand the pre-made has lead in the compound which creates a lead button when firing?

Or what are you doing in the firing of this? I have 2 different furnaces that will go over 2000 F and crucibles. One is specifically for melting metals like gold and silver using a graphite flask.

I'll use my respirator to check the iodine solution I have going right now and will connect the aquarium air bubbler to my next batch (thanks!).


----------



## MacDaddy

Just starting to experiment with this technique.
I put a small bathch of gold plate pins in a test tube with Lugol's iodine. The gold stripped off in about an hour or two at room temp. No fumes.

The liquid turned a clear yellow color with a white granular precipitate. The yellow liquid had some gold fizz around the rim typical of dissolved gold.

Then I used Lugol's to take the gold off of the small pins from a number of K6 CPU's. Not much else to get. I noticed that as the lLugol's turned clear, the stripping stopped until I added more Lugol's. I assumed that the iodine had been bound up in the gold and cleared the solution, but I don't know that for certain. I haven't tried just adding HCL to the spent Lugol's, but if there's no iodine left to act on the gold, what's the object?

The original patent precipitated the gold with high alkalinity, so keeping it acidic will keep the gold in solution, but I don't know if it will enhance the stripping or not.

The white precipitate can be filtered off best with a LOW vacuum filter flask (otherwise it sucks a hole through the filter paper). I don't know what the white stuff is, but there's not much of it.

I have tried the tin solder in HCL for testing presence of gold, but not experienced enough. Going to make soem standardized gold solutions with known gold concentrations for testing purposes. I don't trust my stannous chloride mix...yet.

Comments?


----------



## lazersteve

MacDaddy,

The stannous chloride won't show proper results due to the iodine. The iodine solution will blacken when the stannous chloride is added and this prevents you from determining if gold is present or not. 

I tried some iodine solutions when this topic was originally posted and didn't have good results. My gold was still on the original parts, merely discolored by the iodine. I found this out when I rinsed the original parts with muratic, the gold showed back up when the iodine layer was removed. The iodine only removed a very small amount of the gold. My tested solutions also changed from clear to pale yellow and back again a few times. I managed to percipitate some copper iodide (? looked like black rat pellets) out of a small amount of the iodine solution with lye. Since the gold was still on the parts I haven't done anything with the remaining iodine solutions.

Steve


----------



## goldsilverpro

While working for a man that later became my partner, Richard Homick wrote an iodine patent that supposedly was the best. I never tried it but, I heard about it almost every day. The patent number is 3957505

http://www.google.com/patents?id=oLZ7AAAAEBAJ&printsec=abstract&zoom=4&dq=3957505#PPA3,M1

To find out the basic formula, go to page 4 and read the "Example" section at the bottom of the page.

Iodine and potassium iodide are expensive but, the beauty of this formula is that the chemicals can be recycled with hydrogen peroxide and used over and over again. People have asked for something that could strip gold plating selectively. This could be it. I haven't tried it because, at the time, I was perfectly satisfied with cyanide stripping. I would behoove everyone to check out this patent.


----------



## rainmaker

I have used Iodine with good results. It can be very selective and is somewhat slow. Yes as you will see, you can recover the Iodine and re-use it. Here is the procedure I use.

IODINE LEACH PROCEDURES

1. Mix in clear container:
1 part scrap ( may contain Gold, or any of the PGMs)
1 part 7% or 10% iodine
10 parts water
Agitate (I use a bubbler like used in a aquarium)
Let set (Leach) 24 – 48 hrs-should get darker (the darker the better)
Filter to clear (3 coffee Filters)
filtered leach will be clear but colored
Retain clear leach 

2. Drop Iodine:

Add ½ t of Sodium Nitrate 
Wait to drop
Filter

* Alternate procedure:*
Add Clorox slowly (Iodine will coagulate & drop as blue layer/black precipation)
Filter (to remove Iodine)

(Keep the Iodine in a covered container, as it will vaporize in air.)

3. Drop PGMs:

Mix equal parts Clorox and household Ammonia in small amount, use fresh.

Add small amount to Iodine free leach to precipitate yellow powder (Platinum)
Filter & dry (3 coffee filters)

Wait 1 hr
Palladium should fall out as dark precipitant
Filter & dry (3 coffee filters)

4. Gold:
Gently raise leach pH to near but not over 7 with Sodium Hydroxide (lye solution), pH will continue to rise as gold falls out. White precipitants are Mono-atomic.(you got the pH above 7)
Wait to complete drop, gold should fall out 
Filter with 3 coffee filters to clear


CAUTION:
Mono-atomics: Become radioactive when heated. It's best to just discard them, it is very unlikely that any of us amiatures can coax it back to a non mono-atomic state
  

I obtaine this procedure from Mike . Here is the link, but the information is no longer available free. Now you have to buy the report and all of this is not in there. I got it when He had it posted openly on the site, several years ago. 


http://www.goldmineworld.net/

Her is another patent you might find interesting since is based on this procedure

Rainmaker


----------



## goldsilverpro

How do you feel about the David Hudson monoatomic thing? Have you ever tested the stuff for radioactivity?


----------



## rainmaker

I have read a fair amount about this and looked at the patent, it is not a simple process by any means. Most of what I have read is very interesting and even the "Lost Books Of the Bible "the Apropha" talk about this. I wouldn't go so far as to embrace some of the claims, but find it interesting enough to want to look into further. 

Never produced any, a little scary.

So much to do, and so little time.

Rainmaker


----------



## MacDaddy

rainmaker said:


> Mix equal parts Clorox and household Ammonia in small amount, use fresh.



Beware mixing cloroc and ammonia will produce fumes that will knock your socks off. I recommend NOT doing this.


----------



## MacDaddy

Thanks, Rainmaker, for your reply. Your process is undoubtedly slow because of the addition of "10 parts water".

Thanks to others for their replies also.


----------



## goldsilverpro

You're right, MacDaddy. I should have spotted that. Ammonia and Bleach (Cl2) make phosgene, a choking gas used in WWI. This is one of those things they always warn you about mixing up in the household.

The patent I gave uses 1 part Iodine crystals, 4 parts potassium iodide, and 10 parts distilled water.


----------



## rainmaker

Well use your safety equipment!! :? I don't do anything with refining chemicals without my mask, face shield and cloves. Always use glass or plastic containers (recycle 5 or higher).


Rainmaker


----------



## MacDaddy

rainmaker said:


> Well use your safety equipment!! :? I don't do anything with refining chemicals without my mask, face shield and cloves. Always use glass or plastic containers (recycle 5 or higher).
> Rainmaker



Well I like to taste everything I cook and that mask really gets in the way. :lol:


----------



## Gold-Digger

Rainmaker. Thanks for posting that information.

After adding the Sodium Nitrate are you able to re-use the iodine solution?

I bought this *&#^%$ Iodine Leach Report from GoldMineWorld.net and it varies significantly from what you are stating. This would actually be funny if I had not spent 10+ hours and waited for days trying to get good results. Crap!!!!!!!!!!!

I used an aquarium pump to agitate the iodine solution but after about 2 days the solution became completely clear like I had boiled off the iodine. Note: This was done outdoors in 60 to 70 degree temperatures. Did I do something wrong or must the container but air tight or something when using this air pump. Or is this what you would expect?

I just ordered another solution to tinker with using an iodine / Potassium Iodide leach: http://www.unionetchants.com/index.html

They have the Material Safety Data Sheets on the AU-1 Gold Conductor Etchant and it's based off some type of strong Lugol's iodine. But the GOLDOUT parcipitant is a secret mixture. There is a MSDS sheet on this but it won't say what's in it. They did state this GOLDOUT does destroy the iodine mixture meaning it cannot be used again but then again they make this for semiconductor applications. Maybe for what we're trying to do it might work a 2nd or 3rd time by doing some items such as checking the Ph and possibly lowering it down to 4, etc? Any ideas....


----------



## rainmaker

It sounds like you might have processed your batch in an uncovered container. It is not necessary to seal the container but you need to keep exposure of the leach to air to a minimum. The bubbler increases the exposure to air but the evaporated iodine seems to return to the mixture in a closed container. I would test the clear solution to ensure that there is no AU in it prior to disposal. There is no appreciable pressure buildup with the iodine leach process, but it should be kept covered, air tight is not necessary. 

I don't really think the bubbler is necessary with scrap recovery, the process was originally designed for use on low grade ore.

As to what to expect, I am at a loss since I've always processed my material in a covered 1 Gal glass jar with a lid on it.


----------



## Gold-Digger

GoldSilverPro - what recipe or patent are you sucessfully following using iodine leach on gold? Also, I would be interested in buying this from you along with the plans for making nitric acid per your other posts.


Rainmaker - I started following your directions (I have a small batch brewing per your instructions in my garage right now.) There were a couple questions I wanted to clarify:
1. You are not adding any acids (HCl).
2. After you filter the solution to a clear leach. I wanted to confirm you are dropping the Iodine with Sodium Nitrate and filtering before getting the gold?
3. Can I skip step 3 (Drop PGMs). I don't see where this would matter that much. Or is this a critical step?
4. After the step of raising to near Ph7 and dropping the gold. Are you then adding more Sodium Nitrate or lye or anything to drop any additional iodine. Or is all the iodine all gone from step 2 anyway? 
5. Are you using Potassium Iodide to get the Iodine back into solution? Or what are you doing?

Thanks for the help! If you wanted to write up some detailed instructions I would be happy to buy them.


----------



## rainmaker

"1. You are not adding any acids (HCl).
2. After you filter the solution to a clear leach. I wanted to confirm you 
are dropping the Iodine with Sodium Nitrate and filtering before getting 
the gold?
3. Can I skip step 3 (Drop PGMs). I don't see where this would matter 
that much. Or is this a critical step?
4. After the step of raising to near Ph7 and dropping the gold. Are you 
then adding more Sodium Nitrate or lye or anything to drop any
additional iodine. Or is all the iodine all gone from step 2 anyway?
5. Are you using Potassium Iodide to get the Iodine back into solution? 
Or what are you doing? "

1. no acids.
2. correct
3. yes you can skip, but doing so will cause any PGMs to be in your gold
4. no, there should be no iodine left in your solution.
5. no, just start a new batch and add it to the new solution and dilute as 
appropriate to obtain desired strength.

I will set down soon and make up a procedures sheet, this process is not copyrighted or patented. This procedure has been used for decades and is in the public domain. There is nothing new here, just a well kept secrete.

Rainmaker :? (I don't like secrets) :x


----------



## EVO-AU

Golddigger:
I use Iodine as a leach on the sludge from T/6 leaching. But then, I am working a bench that has some good ore in it. Luck of the Scot-Irish !
Evo-au


----------



## EVO-AU

Golddigger: As to your post about your bout with Iodine Leaching. I did send a thread to you back in Sept, but I got to thinking, Iodine will gassify or evaporate at room Temp. To repeat myself, Iodine workd well with my ore, so maybe it is your ore. Did you pulverize down to a workable mesh ? I work with -30 to -80. Every ore is different, maybe yours will not work with Iodine. Don't fault the messenger (Mike ), look to your own methods first. No disrespect meant. I've talked with Mike on the phone and another member of this forum has met him in person and we find no fault with him or his publications.

EVO :roll:


----------



## Irons

EVO-AU said:


> Golddigger: As to your post about your bout with Iodine Leaching. I did send a thread to you back in Sept, but I got to thinking, Iodine will gassify or evaporate at room Temp. To repeat myself, Iodine workd well with my ore, so maybe it is your ore. Did you pulverize down to a workable mesh ? I work with -30 to -80. Every ore is different, maybe yours will not work with Iodine. Don't fault the messenger (Mike ), look to your own methods first. No disrespect meant. I've talked with Mike on the phone and another member of this forum has met him in person and we find no fault with him or his publications.
> 
> EVO :roll:



There's a big difference in working with ore vs Jewelry scrap. With scrap, the variables are few. With ore, everything can change within a few feet or even inches in a mineral formation. Untill you know exactly what everything the ore contains and how the compnents interact, it's very difficult to work out a process flow.


----------



## aflacglobal

> Untill you know exactly what everything the ore contains and how the compnents interact, it's very difficult to work out a process flow.


 AMEN !!!!

Oh my head hurts. I have been going thru some ore mineralogy charts today. This is a whole different world.


----------



## aflacglobal

:arrow: :arrow: :arrow:


----------



## EVO-AU

Irons: Man, you have got that right. In my ore within even the same solution, the results can be mind-rending. Great to absolutely nothing. EVO :?


----------



## EVO-AU

Alflacgolbal: Have you ever read LaRunes' - 'Rockpecker Notes" ? Kind of picks up where Dana left off. He consolidates mineral testing down to an easy to understand set of rules or tests. Whatever ! A great reference manual. EVO


----------



## Irons

EVO-AU said:


> Irons: Man, you have got that right. In my ore within even the same solution, the results can be mind-rending. Great to absolutely nothing. EVO :?



..and about the time you figure out where the pay streak is, some peckerwood goes in there with a dredge and stirs it up real good.


----------



## EVO-AU

Irons: Yeah, there are a bunch of those goofs around. The trick is to, with shovel in hand, go upstream and roil the mud. Boy, talk about startin' a war. HEH ! HEH ! :lol:


----------



## OMG

> I noticed that as the lLugol's turned clear, the stripping stopped until I added more Lugol's.





> after about 2 days the solution became completely clear like I had boiled off the iodine.



I was just reading wiki about copper iodide and it made me think of this thread. Maybe somehow copper is reacting with the iodine and precipitating the CuI? (using up the some of the iodine in the process)
Check out the preparation section: http://en.wikipedia.org/wiki/Copper(I)_iodide

It says you need a Cu2+ ion in order to bond with iodine, so there would have to be a different reaction taking place to get to that stage. But if the liquid turned clear and precipitated a white substance once some of the gold was stripped away (exposing some copper in the process) it seems like it could be something to think about.


----------



## Traveller11

Gold Silver Pro

I went to Free Patents Online and looked up Patent # 3957505; the patent filed by your friend and partner Richard Homick that proscribed using iodine and potassium iodide to leach gold particles.

I must admit that I was a little overwhelmed with most of the literature but, as you advised, the example at the end brought everything into a simple step-by-step procedure that even a dumb logger such as I could comprehend LOL.

This procedure, though expensive, does have the beauty of recycling its basic components for what seems to be an infinite number of cycles. I am also impressed with the non-toxic benefits and not having to dispose of hazardous wastes.

I do have a couple of questions though. In his patent, Mr. Homick touches briefly on iodine vapours and mentions that it might be wise to take protective measures during the leaching stage. How dangerous are iodine vapours? Would a fume hood and filter mask be adequate?

Perhaps I should mention at this point the type of gold I am trying to dissolve. It is a concentrate from a beach placer that is mainly clay and -100 mesh flake gold. The most I would be trying to work with is roughly two gallons of concentrate at any given time.

The other question I have has to do with the addition of a buffer to reduce the accumulation of salts during the reduction and precipitation stages. Although Mr. Homick goes into great detail about which chemicals are suitable as buffers, he does not mention at any point what volume of buffer to add or at what point in the procedure to add the buffer. Would you by chance happen to know the details of adding a buffer?

I don't suppose you would know how to contact Mr. Homick directly would you? I would, of course, respect his privacy if he so desired but I would also consider it an honour to be able to communicate with a man of such obvious intellectual ability.

Bob


----------



## goldsilverpro

It's been 30 years ago, in the Silicon Valley. Homick worked for a man that later became my partner. Homick's background was in printed circuits. I have never met him. I can't even remember my partner's name - the partnership didn't last long. All I remember is, that my partner went to a Rosicrucion temple and that he read palms in bars to get women. 

I have recovered the gold from many iodine strippers used in electronics manufacturing, but I've never used the stripper, itself. I was very satisfied with cyanide. One of the beauties of cyanide is that you can destroy it. Until today, I hadn't read the iodine patent in 30 years.

A fume hood would be adequate. A good fume hood requires at least 100 cfm per sq.ft. of open area. Since iodine and chlorine are both halogens, I would expect a similar strong odor. Just a little bit would probably notify your nose that you were breathing the fumes.

You're right. The best things about this are that you can reuse it and that it's reasonably non-toxic. 

You might have trouble using this on placer gold. Unlike plated gold, it always has some Cu, Ag, and other stuff alloyed with it (usually from about 2% to 35%, total). I2/KI is quite selective towards gold. It may, or may not, dissolve the particular alloy. Test with very small experiments. Also, rinsing would be critical, in your loose materials. Poor rinsing loses I2. You probably should save your rinses for I2 recovery. 

The buffer thing is vague. It, as buffers do, mostly eliminates the need for pH adjustment. However, you have to start somewhere. Maybe, 1 or 2 ozs/gallon for start-up. A buffer is a buffer. Between certain concentration limits, you will get the same pH buffering (stability). He says the best pH is between 6 and 8. Check it after adding the buffer. You probably need a meter. 

He also doesn't tell you how to extract and collect the iodine, for making up a fresh solution, when the Cu, Ni, etc., gets too high. I would guess you use distillation.


----------



## ChucknC

If your going to work with placer gold material, you need to concentrate it way down before you even thin of leaching it.
I posted this link before, but it will give you an idea about how to process the material.
http://www.youtube.com/watch?v=KdikUKNLCHY
Remember, crush the concentrate as fine as possible. This will free the gold and make classifivcation and concentration that much easier.

Chuck


----------



## EVO-AU

Digger: 7 % works for me, but it is turtle slow ( about 72 hours average ) Acid should be about 0.5 or so and do stir frequently. EVO


----------



## eagle2

Traveller11 said:


> The other question I have has to do with the addition of a buffer to reduce the accumulation of salts during the reduction and precipitation stages. Although Mr. Homick goes into great detail about which chemicals are suitable as buffers, he does not mention at any point what volume of buffer to add or at what point in the procedure to add the buffer. Bob




If you read the patent fully and carefully, you can infer that the buffers are added to the Gold precipitant and the Iodine regeneration is done with H2O2.

Al


----------



## Palladium

Meow !!!


----------



## eagle2

Hey Pd, I bet you like cats. 

Many thanks for all your work on the handbooks and the Youtube video.

Did you ever hear a mountain lion scream in the middle of the night in the mountains about 100ft from your tent?

Happy holidays to all. ---- Al


----------



## Shecker

I have a very good report on leaching gold from stream sediments with iodine. The recovery method is most unusual. If someone will pm me I will send to them for posting on the forum.


Randy in Gunnison


----------



## Shecker

Here is what the report proposes for precipitating gold on a selective basis and recycling the lodine leach solution. Make a hot saturated solution of ascorbic acid (Vitamin C) and add the leach solution slowly until all of the gold is precipitated. This works. The gold comes out a dark yellow color and the iodine solution is reusable. No pH adjustment is required.

Randy in Gunnison


----------



## eagle2

Randy, I have used Ascorbic acid as a preciptiant. It works well within a proper Ph range from Chloride solutions.
But on this method with Iodine leach, I don`t see how the Iodine leach solution is quickly re-used. Because the excess Ascorbic acid has to be removed. You would have to precipitate the Iodine, then re-make the leach solution.

Al


----------



## Platdigger

That is just what they state at the end of the report....that they did not have a good way to recycle the iodine.


----------



## turbo

Hi Guy's  

Long time no posting here.
I was wondering if anybody figured out how to reuse the iodine??

Turbo.


----------



## Richard36

Obviously not, but I would like Shecker and Eagle2 to continue the discussion. I am interested. Any one else have anything more to add?


----------



## GoldDigger2009

Are there any Chemist Pros in this forum, who can solve the problem and know how to get the Ascorbic Acid out of the iodine leach. Would be interested to hear is somebody can solve this problem.


----------



## GoldDigger2009

Hello fellow Refiners,
I am looking for the"Iodine Leaching Manual in pdf" form fom Gold World ,does somebody have one and would like to share it with me. If you would like to share please PM me.
Thanks so much for you help.


----------



## solar_plasma

> CAUTION:
> Mono-atomics: Become radioactive when heated. It's best to just discard them, it is very unlikely that any of us amiatures can coax it back to a non mono-atomic state



sounds like an urban legend to me...does anybody know the source of that theory? Maybe if you heat them to some million degrees celsius by letting them collide at 90% of lights velocity? Sure, then you will get radiation from every kind of particle. Radioactivity comes from the nucleus - always. Radiation that does not come from the nucleus isn't radioactivity. You cannot change anything in the nucleus by chemistry! Sky is blue, water is wet and you cannot change anything in the nucleus by chemistry.


----------



## trashmasters

I can't belive that in all this discussion on IODINE , nobody has said anything about Dr. Ted Williams.  He wrote many papers on gold recovery and had a web site.. Try to find the web site or info on him. Hedid a lot of work with IODINE from start to recovery for reuse.

Wish I had the info but I don't...

Hope this helps


----------



## butcher

Apparently there are several forms of this Iodine leach, I concentrated my study on the basic triodide gold leach, staying away from the ammonium Iodide as I understand it could be an explosive.

Iodine Iodide 
Note: I have not used it, and have only done some study on it, and this is the way I understand the process.

Just a little information on this Halide leach:


Iodine (I2) is much more expensive from chlorine, as iodine comes from seaweed kelp being a main source.

It is my belief it would be harder to dissolve and precipitate gold from this solution as easily as we do with the chlorine halogens, iodide solutions can be used to leach ore, but I really do not know it is that popular in the mining industry, expense of the leach, and other related factors.

When I buy iodine by the gallon for treating Horse hoof thrush I have to give them several forms of ID my name is added to a list turned over to authority's of who bought the chemical from the farm and feed store, I guess it is used in illegal drug making and is a highly watched chemical now a days,I cannot even get it from the pharmacy any more.

Iodine in its elemental state is oxidized, it is in this state that it is needed to react with gold to dissolve it (oxidizing the gold and in the process the Iodine is reduced), problem is in this state it is a blue black solid which will not dissolve in water (only very slightly soluble), potassium iodide (KI) is the reduced state of iodine which is a liquid, the iodine will dissolve in this potassium iodide solution forming (KI3) triiodide (Lugol's solution) basically three iodide atoms, so now we can dissolve gold with this solution.
KI + I2 -->KI3

After gold is leached into the iodide solution (red brown solution), Sodium Hydroxide (NaOH) can be use to reduce the iodine in solution to iodide and precipitate the gold, at this point the solution will go more colorless as the sodium iodide (NaI) which is colorless, gold being impure is a black powder.
I2 + NaOH -->NaI

Iodide (I) can be oxidized back to iodine (I2) with chlorine (or with sodium hypochlorite also called bleach).
2KI + Cl2 --> 2KCl + I2
If excess chlorine a solid iodine would form.

Silver nitrate (AgNO3) and potassium iodide would form silver iodide (yellow silver precipitant) and potassium nitrate solution.
AgNO3 + KI --> AgNO3 + KNO3
This silver salt, like the silver chloride salt is light sensitive, and can be used in photography; the light can reduce the silver to elemental silver metal and iodine.
2AgI--light--> 2Ag + I2

Unlike silver chloride, silver iodide is not soluble in ammonia solutions.

here in the above discussion the iodide is normally oxidized and the iodine is reduced when it reacts to ozixize the gold into solution, and gold is oxidized to a potassium gold iodide solution and sodium hydroxide used to precipitate gold and reduced remaining iodine, the iodide leach is reusable, by oxidizing it back to iodine (mixed or dissolved in potassium iodide to form triodide ready to dissolve more gold).
At least this is how I understand what I have studied so far.
Butcher


Some links for further research:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=44&t=15411&p=156236&hilit=IODINE#p156236

http://www.freepatentsonline.com/result.html?query_txt=iodine leach
http://www.google.com/search?hl=en&as_e ... s_occt=any
http://www.freepatentsonline.com/result.html?query_txt=iodine leach
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=5690&hilit=IODINE
http://webpages.charter.net/kwilliams00/bcftp/bcftp.htm


----------



## solar_plasma

> staying away from the ammonium Iodide as I understand it could be an explosive.




yes, NH3 and iodine will form nitrogene iodide, which ist quite dangerous when it is dry. A fly, that would try to land on it, would blow itself in the air. It's an old demonstration experiment, but I've never tried it - and I don't want to! :lol: ...so never let iodine come in contact with NH3 - its non-predictable unless you are a) a chemist and b) know really and exactly, what you are doing, c) have a safe place to do it and d) are allowed to do it by law.

Thanks for the links! I have read a lot about it since last. I think I can start my leaching project with safe material like ram-pins (only Cu and Au). Connector pins and ICs have to wait untill I've solved some questions.

cobber iodide isnt soluable
nickel iodide is soluable, but since the goldlayer is thin and the reaction slow, it wont be so much nickel to deal with in the waste
tin iodide is very poison....on the other hand nickelsalts are very poison too. So maybe I am only a little too anxious.
arsen could be a problem in ICs, but leaching ICs seems to be quite normal after all, though cancerogene it is still used as rat poison,in accumulator lead and in agriculture

I'm sure the leach will cumulatively be loaded with highly dangerous material with every re-use.


----------



## Lino1406

Some completions:
1. KI + I2 dissolve gold as KAuI4
2. To get the gold you add NaOH, as was said
but you will get an iodide precipitate. Wait
24 hours.
Decant the liquid and HEAT the precipitate
with fresh NaOH. Only then you will be able
to check the gold with HNO3 (not giving
out iodine sublimate)
This procedure appears in "29 recovery procedures"


----------



## solar_plasma

Maybe redundant, but I think it's worth posting here:

I have tried some different probes to process with iodine/iodid and my experiences are:

only gold like glucose test strips - top
only gold on copper like RAM - top
plated pins with only a bit solder - very bad compared with a cell (white precipitate, maybe nonsoluble lead iodide, silver iodide and/or stannous hydrates, :evil: much work to find out later)

pro: if treated well, not much waste / all iodine can be recycled / doesn't take copper / takes Au and PGM in one process
contra: though it's less dangerous (could be a nice school experiment with non-contaminated gold), it is still more something for (bored) professionals

conclusion: very special, in some very few constellations (material/person/place) may it be one of the best alternatives, for all teachers a MUST HAVE TRIED

Have a nice day!


----------



## solar_plasma

> all iodine can be recycled



But that may be as easy as read, if you use only iodine. Then it's slow and weak because of the little amount of iodine that is soluble in water. 

Williams method to get iodine back from iodide didn't work in my experiments, it stayed dissolved, didn't want to precipitate. Still searching the texts where I got something wrong.
To get the iodine out of the iodine/iodide by widely known methods will be much work. Traditionally it must be extracted from the brown solution with some non-polar dissolver, which then must be destilled off.....possible, but not really economic.

AND iodine/iodide obviously likes nickel  I used 600ml iodine/iodide on 600g 50%-plated pins (not rinsed of solder - big mistake!), the gold is not complety gone, there is yellow-white pricipitate and DMG seems to be positive on nickel (pink precipitate, but I didnt use NH4OH! :shock: ). DMG is negative on palladium. 

Now I will run the batch with the good old sulfuric cell, which works fine for me. 

Still, I will store iodine-leaching in my repertoire for two cases:
a) as a school experiment with pure gold on unused diabetic strips or gold leaves
b) for full-platings with plastics that can't/must not be removed as for some kind of transistors (don't open or smash them them: As, BeO) as long as I don't dare cyanide-leaching

*Edit: Forget "b)"! And cyanide has to be treated by professionals with professional equipment and sealed systems. What is left over is, that I think iodine etching is interesting, but no alternative to the common methods of small quantity recovery.*

I hope this helps others.


----------



## quisno

iODINE Leach ok why im giving this. I dont know why im doing this but some need help ok
1. 7 to 10% iodine (providone) 
2.M uriatic acid 33%
3. Sodium Hydroxide
4. 100 mesh zcreen 
ground ore w ater to absorb powder 1 ounce ore powder add 2 oz i Iodine from feed store add 33%% muriatic acid( thats 33% hcl in should be at 450 to 475 ORP Meter. in gallon jar or plastic jar 3/4 full ORP wil be under 900 no irons must be picked up yet ph at 2 or below no less than .1 drops of hcl if needed. color will turn from red to brown. pour off carefully leaving residue rinse and repeat water should contrain gold silver and pgm's now lixiviant is AT NEUTRAL (.7}. sodium Borohydride USE for precipitant you need lots of hydrogen that ultimatly reduces all metal salts to native metals or try T 6 before getting rid of bring ph to 7 using sodium hydroxide.


----------

