# An alternative passive stripping system



## Shecker

I have been experimenting with another passive stripping approach to e-scrap that seems well suited for such things as cpu's, pins, fingers, monolithic capacitors, etc. I've been using a dilute solution of veterinarian grasde Povidine Iodine. I make an iodine solution that has a thin red color (iodine water). This dissolves gold, silver, platinum, palladium, but does not react with lead, tin, aluminum, or copper. As the solution begins to become saturated it starts dropping out some discrete particles of precious metals. It will continue to do until the solution looses it stability and goes clear. I ran some CPU's today and after about two hours the precious metals were laying in the bottom of the container. No precipitation was required. Forum members working with iodine may give this try and report their observations.

Randy in Gunnison


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## Platdigger

Hi Randy, 
Did it strip the cpu's clean?


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## Shecker

As long the pm's were exposed and the iodine solution was still active, yes it completely stripped the pm's.

Randy in Gunnison


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## Platdigger

Sounds great. About how much iodine per say...a gallon of water would you say?


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## Shecker

Just enough to make the water reddish-brown but you can still see through the solution. If the mixture becomes opaque add more water.

Randy in Gunnison


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## patnor1011

what is the brand name and concentration of that iodine? isnt it Povidone iodine?


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## dorki22

patnor1011 said:


> what is the brand name and concentration of that iodine? isnt it Povidone iodine?



Yes, its Povidone in my country too 8) 

Simon


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## Shecker

As the iodine is exhausted tiny bits of metal will fall to the bottom of whatever vessel you would use. There will also be a golden yellow solution left over which still contains gold. I recover most of that on carbon but I am still working on the residue gold left in solution.

Randy in Gunnison


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## patnor1011

can this be used to make solution you are talking about?
IODINE CRYSTALS 50g Top Quality Material 99.9%
Ebay Item number: 120462660705


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## qst42know

I would guess Povidone Iodine is just a convenient source of elemental iodine like you found on eBay.

http://en.wikipedia.org/wiki/Povidone-iodine

I have read some things on iodine leaching but never really studied the process. You should be able to recover and reuse the iodine repeatedly.


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## evolx10

Well as with quite a bit of our supplies, http://www.usdoj.gov/ndic/pubs1/1467/index.htm..


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## roddenberry

This is a very interesting alternative. I was a bit weary of using Aqua Regia even though I have access to HNO3 and HCl... I'd much rather use this process, which looks much less dangerous. Does this process generate noxious or oxidizing gases? Can it be done indoors or is it preferable to do this outdoors?

I imagine this process must be quite slow (but I don't mind). So the metal precipitates directly at the bottom of the container? i'll try it on a handful of old gold-plated semiconductors to see if it works!

Robert


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## LeftyTheBandit

evolx10 said:


> Well as with quite a bit of our supplies, http://www.usdoj.gov/ndic/pubs1/1467/index.htm..


 
Oh great... after visiting that sight I bet big brother just tagged me.. Arg!

I already had the boys in blue show up to my house to know what I was up too. Took them on a tour of my set up... they wanted to know how to do it themselves... Ha!


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## Wyndham

I wonder if Betadine (I have a pint bottle)which is a stronger solution of drugstore iodine would also work, I guess it should.
After you filter the precipt out then would you filter thru activated charcoal or use some zinc or iron salt(forgot the name)? Which would work better?
Wyndham


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## Gold Trail

allrighty, heres a question......

If this solution "self precipitates", i would guess the crushed cpu's or pins would have to suspended in some sorta basket, as having the precipitation mixed with the materials would not be practical?

ryan


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## Wyndham

I was thinking of a plastic strainer for testing. I found out that Betadine is provodine at 9-10%.
What do we use after cleaning up and dropping the gold out of solution to recharge the iodine?
BTW it was iron sulphate, I think that I was referring to, to drop the gold out of the remaining solution.
Wyndham


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## roddenberry

Hello all, 

Seems my first attempt at gold recovery was less than a stellar success... 

Since I have no access to a fume hood and I live in a densely populated area, the Aqua Regia process would be very hard for me to attempt, so I decided to try out the iodine solution process.

So I attempted the experiment on a small scale to see if it works, and since iodine dissolves better in ethanol than H2O, I used that instead, but I decided to have a more concentrated mixture than recommended by the OP to see how fast it works.

In a small 50 ml flask, I added:
15 ml of Proviodine 7.5%
20 ml of ethanol 50%







Then I dropped a small piece of Pentium in the flask and I put a cork stopper on top. I let the mixture sit for over 48 hours, thinking that I would have my little pentium chunk stripped clean of gold, but to my surprise, the pins and the gold traces on the creamic substrate were totally unaffected.

So either I did something wrong, or the process itself takes a very very long time... The OP mentioned that he only used water and his mixture was just a "thin red color". My mixture was much more concentrated than that. So before attempting anything on a larger scale, I just wanted to ask the fine members of this forum who had success using this process if they have any recommendations, mixing ratios or suggestions they could share with me... 

Robert in Montreal


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## eeTHr

roddenberry;

Being a beginner myself, I have not yet earned the right to rant or have pet peeves (with a small exception in the _Bar and Grill_ section).

However, I would like to say that I am always confounded when someone states that they tried a certain formula or prosess, when in fact they have actually _altered_ that specific formula or process! The way to test something like that is to _duplicate_ what was stated, exactly. Then if a person wants to try to improve it, fire away, and maybe you can make something better. But don't skip the step of duplicating the stated method first!



roddenberry said:


> So either I did something wrong....


Hmmmmmmmm.




roddenberry said:


> members of this forum who had success using this process....



The original poster of the process says he had success, and he has listed all about how to do it. What's to question?

Actually, I've mis-applied processes myself  , thinking I would outsmart the experts, but surprisingly :roll: none of those attempts succeeded. But I'll always try to _improve_ something once I have gotten it correct, if I have a good enough reason to think it would be likely to work better. And maby it will work, and maybe not, but at least I will have _a working reference to judge it by_, which would be the duplication of the process as stated to begin with.

Well, now that I haven't ranted, maybe one of the experts can tell you what happened to your process. :lol: 

Sincerely,
Don


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## roddenberry

Hello Don, 

Sorry that I am the target of your rant for one of my first posts on this forum... The actual fact is that I have read several documents and texts, including a US patent (3625674) dating back from 1971 that states:
Au + H2O•C2H5OH:I = AuI + H2O•C2H5OH so the only "improvement" on the original poster's recipe was that I followed a more detailed and better described recipe that includes alcohol to keep a maximum of free iodine in the mixture.

I am not a chemist, but I do have elementary knowledge of chemistry and how chemicals react with one another. (always been fascinated by chemistry when I was a kid). Still, I prefer to follow a recipe that has a more precise description of the ingredients. The OP's description was rather vague. One element that isn't mentioned anywhere is the time of the reaction (a minute? a day? a week?).

Anyway, I didn't want to ruffle any feathers with my first post, just get a bit of wisdom from folks who have tried this process and have suceeded. Is heat used in the process? Does the process need a larger quantity of ingredients to "kick in"? Is there a catalyst used? I am simply trying out the process with what I have and gathering more information on the process until it works.

Experience is acquired by a series of trials and errors. My first test didn't work, but it doesn't mean that with a little TLC and a bit of luck, I won't get it right next time. : :lol: 

Robert


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## eeTHr

Robert;

Well, I don't want to ruffle any feathers either, and I apologize to you for being disrespectful.

I, personally, welcome any new methods which would make processing e-scrap more viable; and I feel that the way that would come about is by people like you who get ideas, and then have the wherewithal to actually try them out.

But it does irk me to read, "I tried the process posted above," and then it turns out to have one or more things added or subtracted. I just go "Huh? That wasn't the process!" You know what I mean? Also, it makes me wonder how they would know if it was an improvement over the original method, if they didn't do the original method as a reference?

Anyway, I see what you are saying, and I can't disagree with your logic.

Now maybe someone who knows what's up with your process will shed some light on it.

c u L8r,

Don


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## roddenberry

UPDATE!!

Hot dang! it seems to work! The gold on the substrate is completely gone, and the pins are getting a bit "silvery", showing the metal inder the plating. So I guess I jumped the gun a bit, but my test shows it takes a hell of a lot more than two hours. My count is nearly 60 hours for the process to eat away the gold, and there's still a bit left on the pins.

But I'm not in a rush. My next step will be a small bucket (one liter) containing all my collected gold trimmings from pins, processors and board edges. Since the process is very slow, no heat seems to be generated and no gases either so it seems safe to do it indoors.

Hopefully, I'll be able to recover some gold precipitate, then add more iodine as the solution gets depleted. I'll then filter out the solution of AuI and keep it safe for the next batch.

Robert


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## roddenberry

Hey Don, 

I just saw your reply, don't worry 'bout it... I guess I was a bit hasty in my declaration that my experiment was a dud... And I understand what you're saying... I shouldn't have melded the results of two distinct processes in one post, and I shouldn't have refered to the results of the original poster, but as I say, I'm not a chemist, and any experiment that doesn't involve cyanide, fuming nitric acid or mercury is fine by me! LOL :mrgreen: 

Time to pull out the 1L beaker! :twisted: 

Robert


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## qst42know

roddenberry said:


> In a small 50 ml flask, I added:
> 15 ml of Proviodine 7.5%
> 20 ml of ethanol 50%




I have no experience with this process but Povidone iodine is readily soluble in water what was the ethanol for?


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## lazersteve

Robert,

I have not tried any of the iodine methods yet, but I can tell you that you should try to follow the directions to a 'T' until you understand what's going on and what variables affect the reaction. Once you can reproduce a chemical reaction and understand the fundamental chemistry involved, then you can add your own touch.

I can also tell you that if the formula calls for elemental iodine, you will not have the same luck using povidone. Povidone is a non-staining form of iodine tincture that uses a polymer-like structure to slowly release elemental iodine. For this reason you should liberate the iodine from the Povidone before using it in any formulations that call for elemental iodine. 

I have seen a reaction for removing iodine from povidone somewhere years ago, I think it involves dehydrating the povidone, then subliming the iodine from the resulting residue.

Good luck with your experiments.

Steve


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## Shecker

I am sorry about this but I forgot to add that I add a small amount of HCl to get the pH slightly acidic. That and iodine water. And I don't care if it take takes 60 hours -- that is the whole idea of passive stripping. Mix it up and ignore it for awhile. And yet I do do it indoors.

Randy


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## roddenberry

Hi Randy,

Aah! So we had a missing ingredient! LOL :lol: So your recipe actually produces a mixture of AuI and AuCl. :!: Is the HCl helping or provoking the metal precipitation? Could you recommend quantities of the various ingredients? Is the HCl concentrated (20 Be-32%) or diluted?

So far, I have tried your process with a twist: Au + H2O•C2H5OH:I = AuI + H2O•C2H5OH and it seems to work but rather slowly. Upon reading the details of that formula, I understand that my initial mix had too little iodine so I added a little and the process seems to be chugging along just fine. Next weekend, i'll try to process a boxful of parts and fingers. 

So let me know about the proportion of your ingredients and i'll try a small batch of that to see if the process is a bit faster.

Thanks

Robert


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## eeTHr

Robert;

Also (you probably already know this), be very careful with using alcohol in refining. Personally I don't even keep it around the area---

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

:shock: 

Don


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## Wyndham

Water is harder to make it go bang.  
Randy, would peroxide help or hinder the reaction? Just wondering
Wyndham

Edit: Here's the page on Basement chemistry that talks about Iodine, hope this helps
http://webpages.charter.net/kwilliams00/bcftp/docs/halides.htm


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## roddenberry

eeTHr said:


> Robert;
> 
> Also (you probably already know this), be very careful with using alcohol in refining. Personally I don't even keep it around the area---



Indeed, no nitrates or nitric acid anywhere near my bucket-o-gold :mrgreen:
Robert


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## goaldspektre

Hey guys,
I'm something of a noob but wanted to let you guys know that iodine is toxic and releases toxic vapours(not like regia but toxic nonetheless). This method works because iodine is a halide like chlorine and releases toxic vapours during reactions,always make sure you have some form of ventilation, wear gloves and eye protection.


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## king_joolian

Great idea and link

Do the cpu pins remain intact or do all the base metals just stay in solution after dropping the gold?


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## roddenberry

Yes, the pins seem to remain relatively intact, the other metals don't seem affected at all. I've put the experiment aside for a few days because i've had busy days and evenings lately, but my next test will include more gold plated material including board fingers as well as solder-contaminated pins to see if the lead will be eaten away or remain unaffected. So far it seems like it works, but a chemist friend of mine suggested that I increase the amount of iodine in my solution. I'll resume the experiment next weekend if I have time.


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## shadybear

Shecker said:


> As the iodine is exhausted tiny bits of metal will fall to the bottom of whatever vessel you would use. There will also be a golden yellow solution left over which still contains gold. I recover most of that on carbon but I am still working on the residue gold left in solution.
> 
> Randy in Gunnison


I would like to know how you recover the tiny bits and is this tiny bits of metal gold?
all info I can find on iodine say the pm's precipate after lye is added i wonder if this Povidone has something to do with this.


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## goldmelts

Hi all,

Do we have any updates on this process. Seems very interesting.


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## joem

updates with picture would be great


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## Claudie

I live 8 miles from nowhere, but when I get somewhere that I can buy iodine, I will try this and post the results.


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## glondor

Is this the right stuff?

http://cgi.ebay.ca/250g-IODINE-CRYSTALS-99-8-PRILLED-LAB-GRADE-USP-ACS-EP_W0QQitemZ220711807221QQcategoryZ63512QQcmdZViewItemQQ_trksidZp4340.m263QQ


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## Claudie

I don't think the stuff Shrecker used was near that concentrated, more like maybe 10%. He said he used Povidone iodine, which I think is generally 9%-12%.

I'm thinking something like Wal-Mart sells here: 
http://www.walmart.com/ip/Dynarex-Corporation-Povidone-Iodine-Solution/15648976


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## DarkspARCS

Method for removing electrically conductive materials containing silver from electrodeposited parts



> In the case of a method for removing electrically conductive materials containing silver from electrodeposited parts, in particular, electroformed dental parts, the part is treated with iodine and/or at least one compound containing iodine under at least one processing step. The iodine/compound containing iodine is/are preferably present in the form of a solution or a dispersion in at least one polar solvent. Inorganic iodides and iodophores are prime candidates as the compound containing iodine.




View attachment Process for refining gold and apparatus employed therefor.txt



Here's a relevant patent.
United States Patent 5026420: Purification process for gold-bearing iodine lixiviant



Another ineresting patent

I'm finding that this process is very useable!... Investigtion time... :twisted:


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## DarkspARCS

Ok... I used a half gallon apple juice bottle (top half cut and used as funnel...) as the lixivant chamber and a plastic sobe bottle with its bottom pepper punctured to allow flow in and from its insides to react with plated metal values I filled it with.

I used pm metal plate content from A/V, Comm, Sat, Game console, pc, and telephone, crushed monolithic resistors and caps, pins from various connector types, cut up flatpacks, etched and cut to size, cut up pcb's bearing gold boards, plated jewelry, etc. 980 grams total...

The solvent went clear after 5 minutes, so I added water, shook content, added hcl, stirred content. Added additional iodine.

By the way, was I supposed to use distilled water? I used tap water that had previously been used to break down some of my polymetallic ore from it's solid state into mud, which turned the water light blue. I figured I'd try using it as I'm sure it contains pm values leached fom the ore it was used to break down into componant segmentations.

The red coloration dissipated entirely, leaving what I feel is a very pregnant solution. I added 1 teaspoon of lye and stirred - drk blue elements appeared, then settled at the bottom of the solvent... showing a heaviness in volumn. was the precipitant actully black sludge in blue water?

I think my solutions are saturated, so I'll siphon off the first batch tomorrow and put the leachant in fresh solution... hopefully the pcb boards will then get stipped...

all pm values seem to have been successfully stripped, except pcb boards. Will report back in the morning, after I check the overnight pogress.


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## DarkspARCS

ok, um... I'm wondering about this OP telling us to "add water if solution goes clear to reconstitute the iodine solution".

My solution went from reddish brown to clear opaque like I said, in roughly 5 minutes. Following OP instuctions I added water: no reaction.

I remembered the method using h2o2 to create iodine cystals - so I added 1/2 cup h2o2 (NOT H2O) and the solution reconstitutionalised to a reddish brown.

so...

1. add a little HCL.

2. iodine reconstruction technique - h2o when it should have been h2o2.


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## DarkspARCS

ok. contents stripped, sitting on about 1/2 gallon of yellowish lixivant. there's a white grainy substance on bottom, I'm sure that it's the lye I previously added. how do I use the activated carbon? do I use it in an electrolytic cell? Do I heat the solution? Will cemetation work?

Do I need to filter out the lye? lol, there's so many different methods I've come across, this is your method, let us know how you use your charcoal.


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## jimmyreece

has anybody tried this with gold filled jewelry?


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## DarkspARCS

Activated Carbon took about a day of passive attention in lixivant agitation for it to completely turn the clear bright yellow fluid into a rich dark reddish brown iodine solvant... I'm assuming that the lixivant has been stripped by the activated carbon of values, thus leaving behind (basically, with geater volumn than originally used and possibly stronger iodine to water percentage) a viably reusable iodine solvant.

I've put the impregnated carbon into a large folgers crystals jar, which is filled about 3/4ths full. I'll need to ash it and smelt it to determine what I've got. I suspect a higher silver to gold ratio... as well as some pgm values from proprietary pcb smt stripped along with the flatpacks.

Jimmy... I will just say that this technique will cleanly strip G.F., As long as the gold is directly exposed to the iodine based solvant. Be patient as it will take some time. If solution loses its reddish brown color, add hydrogen peroxide to reconstitute the iodine.

Don't forget to add a small agitant of HCL to the iodine/ water mixture (4:1, water: iodine). if solution loses it's bite add additional shot of HCL 15% (Muriatic Acid). Don't forget to wear your P.P.E. and DON'T breath in fumes, wash exposed areas of skin splashed with solvant immediately, and ALWAYS....

ADD THE ACID TO THE WATER. =)

Capture values in solution with activated carbon (charcoal), ash, then smelt.


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## jimmyreece

do you feel adding some oxgen(small air pump) to the solution would speed the procss up a bit. and how essential is the use of activated carbon, would smb or similar be just as effective in dropping the values from solution and approx what is the ratio between values in solution and the stripped solids (foil) on the bottom of the solution?.......i apologize for the many questions, i am very eager to attemp this method , just seeing which way would be my best approach. thanks


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## DarkspARCS

basically, activated carbon is best in absorpsion of any pm values - esp. coconut charcoal meshes. 

the air pump would serve to continuously agitate the solution through the material being stripped, speeding up the process time and making the solution work more efficiently.


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## Irons

roddenberry said:


> Hello all,
> 
> Seems my first attempt at gold recovery was less than a stellar success...
> 
> Since I have no access to a fume hood and I live in a densely populated area, the Aqua Regia process would be very hard for me to attempt, so I decided to try out the iodine solution process.
> 
> So I attempted the experiment on a small scale to see if it works, and since iodine dissolves better in ethanol than H2O, I used that instead, but I decided to have a more concentrated mixture than recommended by the OP to see how fast it works.
> 
> In a small 50 ml flask, I added:
> 15 ml of Proviodine 7.5%
> 20 ml of ethanol 50%
> 
> 
> 
> 
> 
> 
> 
> 
> Then I dropped a small piece of Pentium in the flask and I put a cork stopper on top. I let the mixture sit for over 48 hours, thinking that I would have my little pentium chunk stripped clean of gold, but to my surprise, the pins and the gold traces on the creamic substrate were totally unaffected.
> 
> So either I did something wrong, or the process itself takes a very very long time... The OP mentioned that he only used water and his mixture was just a "thin red color". My mixture was much more concentrated than that. So before attempting anything on a larger scale, I just wanted to ask the fine members of this forum who had success using this process if they have any recommendations, mixing ratios or suggestions they could share with me...
> 
> Robert in Montreal



You might want to check this .pdf out:

http://www.dim.esdm.go.id/makalah/2006_murakami_CCOP.pdf


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## stihl88

That links broken so try this one http://ebookbrowse.com/2006-murakami-ccop-pdf-d28345212
If you still cant get it to work then I'll upload a copy here.


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## Irons

stihl88 said:


> That links broken so try this one http://ebookbrowse.com/2006-murakami-ccop-pdf-d28345212
> If you still cant get it to work then I'll upload a copy here.



The original link works here in the US. 8)


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## qst42know

Does anyone know if DMG will extract gold from an iodine solution? Leaving the iodine in a reactive state?


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## Irons

qst42know said:


> Does anyone know if DMG will extract gold from an iodine solution? Leaving the iodine in a reactive state?



DMG is specific for Pd (acid medium) and Nickel (basic medium). It will not affect the Gold in the leach.


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## qst42know

Sorry Irons.  

I was thinking of Dibutyl carbitol.

Will a solvent extraction work on an iodine leach.


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## Irons

qst42know said:


> Sorry Irons.
> 
> I was thinking of Dibutyl carbitol.
> 
> Will a solvent extraction work on an iodine leach.



The DBC is miscible in alcohol, so there would not be any phase separation.

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


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## qst42know

Is alcohol a necessary component of an iodine leaching solution?


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## Irons

qst42know said:


> Is alcohol a necessary component of an iodine leaching solution?



Good question. It will work to some degree. Iodine will dissolve in a solution of Potassium or Sodium Iodide. Try it and see.


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## DarkspARCS

I didn't use any alcohol. I haven't checked my charcoal yet, as I've been busy, but hopefully I succeed in seeing values when I do. Niether the OP nor the basement chemist (in his iodine leach version) mention alcohol.

United States Patent 5026420 doesn't use alcohol, but *"a styrenic, strongly acidic cation-exchange resin, to selectively absorb and remove heavy metals from the lixiviant while allowing gold and iodine to pass through the resin"* instead... I'm suspecting that they are referring to the use of corn syrup in that patent.

However, someone else used alcohol, so it's possible that the OP left that little detail out (like the other two items he left out, making alcohol the third item he left out...), and I'm sitting on worthless charcoal if he did.

I'm gonna be hot to trot if that becomes the case, because he would have ruined 3 months of hard work and 1000 grams of my produced materials...


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## trashmaster

No Dr. Williams did not use any alchol,,


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## jimmyreece

can someone explain to me what activated carbon is and how it is used in this process and can the pms just be filtered using standard filters


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## Palladium

Look in my sig line under chemistry handbooks to find more information on activated carbon.


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## DarkspARCS

Palladium said:


> Look in my sig line under chemistry handbooks to find more information on activated carbon.



Thanx Pal !


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## jimmyreece

im sorry, either im not sure on how to go about that or i just cant find it


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## jimmyreece

hey darkspark, were you able to reconstitute your solution after using lye as a precipatant? and it seems like the solution gets saturated quickly or somthing eles is going on because whether i mix the solution acording to the original OP's directions or when i mix it to your's (4:1) , there is always a large amount of pms left untouched.
the diference between the two the weaker solution went completely clear quick, the heavier concentration(4:1) it took several hours for a reaction( a little less than room temp)but when it did the solutuion became thick with a fine yellow powder floating around that took most of the day to settle to the bottom . it went completly clear only wen i added lye.
does anybody know what is taking place with this method, is the iodine suppose to completely disolve the gold or just lift off the gold foils? if that was the case then it would have to be dissolving what the gold was attached to. and why wouldnt a stronger rato of iodine be better? and why is there so much gold left untouched, what is the correct formula in relation to how much gold for how much solution. somebody has to know what chemical process is taking place. it would be much welcomed. thanks


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## DarkspARCS

I initially used lye when another member commented that it was what is used to precipitate gold from iodine... but all lye did was create a brief blue dye cloud then it sank to the bottom. My lixivant still has it on the bottom of the bottle.

I used 3% hydrogen peroxide to reconstitute the iodine durring the leaching process, which after several shots of h2o2 and one small addition of hcl 15% durring that that my pm values all went into solution. I then took out the spent materials (all of which looked burnt reddish brown lol) and immersed activated charcoal into the clear whitish-yellow solution, again, aggitating the carbon filled bottle up and down in the solution several times.

The carbon appeared to be working because there was a bubbling reaction as soon as it was immersed that settled down after a bit. The solution went from clear yellow to a deep dark reddish brown liquid that smelled strongly like iodine after around two to three hours of aggitated carbon immersion. Its my assumption that the solution returing to iodine was the indicator needed to tell me the pm values went into the charcoal... but I could be wrong and my values still sit in solution and all carbon did was absorb impurities.

I'll know more once I ash and then smelt the charcoal.


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## Oz

DarkspARCS said:


> I used 3% hydrogen peroxide to reconstitute the iodine durring the leaching process, which after several shots of h2o2 and one small addition of hcl 15% durring that that my pm values all went into solution.


You do realize that you made AP (acid peroxide) when you used hydrogen peroxide and HCL, right? That in itself will put your gold into solution whether iodide/iodine is in the solution or not.


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## jimmyreece

wow darkspark ! thats strange. well the lye didnt do that with me. it did precipitate everything. im just not sure what everything is just yet. 
i have four different methods brewing right now using the iodine. all four with a different approach and different formula. i havent filtered none of them yet. havent decided which method to use . but what i did notice is the gold would disolve at different rates and forms depending on the PH. the higher the PH the more of a solid (gold) would drop to the bottom. but a ph of 6 or less seems to disolve the gold.so watch your hcl use. i dont see any advantages of using h202 except to reconstute the solution but i dont think it has a direct effect on the disolving the gold. i dont know. im not a chemist but heat did make a difference. i used very hot water to mix with the iodine/hcl/h202 and when i added the solution to the metal it realy took off.
very interesting. and still learning. thanks again for your input


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## DarkspARCS

Oz said:


> DarkspARCS said:
> 
> 
> 
> I used 3% hydrogen peroxide to reconstitute the iodine durring the leaching process, which after several shots of h2o2 and one small addition of hcl 15% durring that that my pm values all went into solution.
> 
> 
> 
> You do realize that you made AP (acid peroxide) when you used hydrogen peroxide and HCL, right? That in itself will put your gold into solution whether iodide/iodine is in the solution or not.
Click to expand...


yeah, I started the whole thing in a retarded way when I tried to leach out the blue from water that turned such when I converted polymetallic ore to mud. then, I didn't include any heat... but worked solely with chemicals.

I am rather confused about how one can reconstitute iodine with water, maybe I'm missing something here.

In either event, the solution did strip the values, and something did occur when I used the activated carbon in the solution that caused the solution to turn from clear yellow to dark iodine. I have the solution still, in a sealed bottle, and may find my values still locked in solution lol. I'll let ya know!


----------



## jimmyreece

that blue may be silver, i now have the same blue that precipitated down after using lye on one of my four solutions.


----------



## qst42know

Here is a good read on leaching with halides. Unfortunately this fellow passed away several years ago so he's not available for questions. The blue may be your iodine. 

http://webpages.charter.net/kwilliams00/bcftp/front.htm


----------



## dtectr

jimmyreece said:


> wow darkspark ! thats strange. well the lye didnt do that with me. it did precipitate everything. im just not sure what everything is just yet.



Sodium is the only metal whose hydroxide (Sodium Hydroxide (Lye)) is soluble in water - therefore, it can be used to precipitate other metals from solution. However, it does not tend to be selective. It also tends to leave a loose, flocculent precipitate. So, if other metals are dissolved in solution, they would precipitate, as well. I'm not sure what you'd be accomplishing in the cases you described. The result would be contaminated gold which would require further refining.



Oz said:


> You do realize that you made AP (acid peroxide) when you used hydrogen peroxide and HCL, right? That in itself will put your gold into solution whether iodide/iodine is in the solution or not.



Did you guys see Oz' comment that HCl/H2O2 will dissolve base metals, or even dissolve gold if the peroxide ratio is too high? It can work the same way AR does, where nitric as the oxidizer, rather than H2O2 with AP (HCl/H2O2). I thought idea of the use of iodine (at least in this post) was to selectively strip the gold without using strong acids or cyanide, not to dissolve the base metals & leave the gold behind, which every other process described here does, easier & cheaper. 

If I added HCl/H2O2 to grape Kool-Aid it would also work to dissolve the base metals, leaving the gold behind. If I mixed it strong enough it would dissolve gold, as well. That doesn't make it a good idea to do so, however.

Maybe I'm missing something


----------



## DarkspARCS

> I thought idea of the use of iodine (at least in this post) was to selectively strip the gold without using strong acids or cyanide, not to dissolve the base metals & leave the gold behind, which every other process described here does, easier & cheaper.



The thread's title said as much... but it appears the title is misleading!



> An alternative passive stripping system
> by Shecker » September 15th, 2009, 2:27 pm
> 
> I have been experimenting with another passive stripping approach to e-scrap that seems well suited for such things as cpu's, pins, fingers, monolithic capacitors, etc. I've been using a dilute solution of veterinarian grasde Povidine Iodine. I make an iodine solution that has a thin red color (iodine water). This dissolves gold, silver, platinum, palladium, but does not react with lead, tin, aluminum, or copper. As the solution begins to become saturated it starts dropping out some discrete particles of precious metals. It will continue to do until the solution looses it stability and goes clear. I ran some CPU's today and after about two hours the precious metals were laying in the bottom of the container. No precipitation was required. Forum members working with iodine may give this try and report their observations.
> 
> Randy in Gunnison



Nowhere in this post - the post starting this topic - did Randy mention using "a small amount of hcl". In his third post, Randy was asked if it worked. He replied:



> Just enough to make the water reddish-brown but you can still see through the solution. If the mixture becomes opaque add more water.



Water to reconstitute the iodine.*Water to reconstitute the iodine?!* This is where I changed 'water (H2O)' to 'Hydrogen Peroxide 3% (H2O2)'. This is how to get your "opaque" mixture back to the active reddish-brown it needs to be to work.

In his 4th post Randy states:



> As the iodine is exhausted tiny bits of metal will fall to the bottom of whatever vessel you would use. There will also be a golden yellow solution left over which still contains gold. I recover most of that on carbon but I am still working on the residue gold left in solution.
> 
> Randy in Gunnison



This is where I got the info on using activated carbon to get my pm values out. I never saw ny 'bits of metal' as Randy described it.

After several people scrutinize his method (one person even including alohol in thier attempt) and report failures... all of them... Randy reappears and says:



> I am sorry about this but *I forgot to add that I add a small amount of HCl to get the pH slightly acidic. That and iodine water.* And I don't care if it take takes 60 hours -- that is the whole idea of passive stripping. Mix it up and ignore it for awhile. And yet I do do it indoors.
> 
> Randy



Now Randy comes back with this 'oops...'. After my little attempt, Oz informs us that this is now no longer an iodine leach but now an AP solution.

This thread, at this point IMHO, is irrelevant, costly, and dangerous. It provided partial info that has cost several folks, including myself, time, money, and now possibly my gold.

If I cant find a viable method in recovering it after ashing and smelting my charcoal I'm going to flag this thread and ask for it to be removed so that other newbies like myself wont be fooled by it, or worse even, be harmed by it.


----------



## DarkspARCS

Oz said:


> DarkspARCS said:
> 
> 
> 
> I used 3% hydrogen peroxide to reconstitute the iodine durring the leaching process, which after several shots of h2o2 and one small addition of hcl 15% durring that that my pm values all went into solution.
> 
> 
> 
> You do realize that you made AP (acid peroxide) when you used hydrogen peroxide and HCL, right? That in itself will put your gold into solution whether iodide/iodine is in the solution or not.
Click to expand...


Lol... :shock: ... Well Oz, It appears that I'll have to treat this as an AP leach now. Please tell me my intuition was correct in that iodine doesn't reconstitute with water... I mean, lol... I posted that fact earlier in this thread AFTER I added water when my solution went opaque (I was following Randy's instructions) and the solution remained opaque. Remembering that iodine reconstitutes with h2o2 I then went that route and my solution (true to form) went back to being "reddish-brown".

How Randy (who has been quiet now since I confronted this issue) recontitutes his iodine with plain water is a mystery to me - Mr. newbie himself lol...

I may find that my charcoal AND what I will have to use to precipitate my solution with will both contain pm values in the end.


----------



## dtectr

Richard,
Thanks for responding. I don't want you to feel that I'm being critical - being extremely new myself, I am VERY interested in a viable passive stripping system. Nursing a nasty nitric burn on the inside of my wrist has also been an incentive. I am just asking for clarification from the community, as you are as well. I've been trying to understand how the system suggested differs from what I already know. Part of the learning process for me.

And I understand your frustration as well - I got derailed at first by bad info. Good thing I'm stubborn! :lol: I have since been able to separate some of the good from the bad, as i build my understanding, not only of the "How's" but also the "Why's". I have a long way to go.
hang in there.
dtectr


----------



## DarkspARCS

wow, sorry to hear about your burn! I've undergone burns too, not through chemicals however, but when I had a damaged 200 amp electrical service panel I was attempting to safe off explode on me... which hospitalized me with 2nd & 3rd degree burns over 20% of my body.

Those things hurt.... :| 

While I'm with you regards a simpler and safer system, which this post appeared to be, those who preceeded me found the process lacking. one person discovered success by following a patented process which included alcohol. My time with it has been a learning process and will continue to be until I succeed in literally learning this new 'trade', or skill.

I truly appreciate those folks like you, and Oz, Lou, Palladium, Harold, Richard, LaserSteve, GSP... I can relate to the folks on this forum, and find the wizards like Irons and Harold extremely educational lol, I sometimes wish people came attached with a readable book... some folks have experience I'd just love reading about!


----------



## jimmyreece

did you ever ash your carbon filter? i ended up with a yellowish/tan sponge. has to be a mix of metals like detecr said because my solution tested negative for pms and thegold is clearly stripped off the material i used. i just need to know from somebody if what i have in filter is nothing that could be harmful when attempting to smelt it.


----------



## Astraveller

It’ a long time since I last posted anything but I have been following this thread with interest. So much so that I took a bunch of gold plated bits and pieces and put them in some Iodine and left them for a few days.
Sure enough, the gold plating has been stripped and the base metals remain ,apparently unaffected.

I used iodine that I was able to obtain from a local farmers cooperative, it is Iodine 10% and Potassium Iodide 6%. I covered the components with about 400 ml of water and added 40 ml of the Iodine. In about 48 hours the liquid was clear and the fingers, cpus etc were stripped of gold and 2 days later the base material still had not been attacked as far as I could tell.

I did add a capful of hydrogen peroxide at the beginning, which I now regret because it was an unnecessary variable but it didn’t seem to have any affect. 

At the beginning of the process (and I’m sorry I didn’t take a picture) the mixture was almost blood red and too dark to see through - over time it became lighter and eventually transparent. When it became transparent I noticed that most of the gold plate was gone but not all. I left it for another day or so and then all the gold plate was gone. And, as I say , the base metals are still intact.

The Pyrex jar now contains :-

De-plated components.
A Clear liquid.
A yellow or golden sediment that seems very light ie. Is easily disturbed and is not heavy.

Conclusion: The Gold has disappeared.

Assumption: It should be it the liquid or in the yellow sediment.

Question/s: Which? And how to get it back?

I realise that this post does not add to this thread very much but I would like to take it step by step to see if this idea has legs. I have downloaded all the links that have been provided so far and have read them and have endeavoured to understand them as far as my puny human mind can.

These are my results (photos) -settled and all shook-up. Any thoughts and reports would be welcomed.


----------



## Aristo

I have seen some members of this forum reprimanded, censured or had their priviledge revoked for a variety of reasons ranging from obscene and rude behaviour or to lesser infractions.
I would ,politely, like to question the moderators as to why the OP has not been reprimaned for apparently leading on falsely or misleading unsuspecting and honest enthusiasts who are simply trying to learn. 
I do believe that there is a wealth of information and experience to be gleaned from this forum, however, there should be some examination of the posts by the "proven experts" prior to its publication or use. In the science of chemistry and metallurgy, there is no magic or as someone put it, witchcraft. Whether it is electronic scrap, ore or related precious metal bearing products, they are all governed by known science.
I would like to kindly urge those that are responsible to review this matter and, if there are no known scientific proof to what is being presented, some action should follow.
Thank you. 


DarkspARCS said:


> I thought idea of the use of iodine (at least in this post) was to selectively strip the gold without using strong acids or cyanide, not to dissolve the base metals & leave the gold behind, which every other process described here does, easier & cheaper.
> 
> 
> 
> 
> The thread's title said as much... but it appears the title is misleading!
> 
> 
> 
> 
> An alternative passive stripping system
> by Shecker » September 15th, 2009, 2:27 pm
> 
> I have been experimenting with another passive stripping approach to e-scrap that seems well suited for such things as cpu's, pins, fingers, monolithic capacitors, etc. I've been using a dilute solution of veterinarian grasde Povidine Iodine. I make an iodine solution that has a thin red color (iodine water). This dissolves gold, silver, platinum, palladium, but does not react with lead, tin, aluminum, or copper. As the solution begins to become saturated it starts dropping out some discrete particles of precious metals. It will continue to do until the solution looses it stability and goes clear. I ran some CPU's today and after about two hours the precious metals were laying in the bottom of the container. No precipitation was required. Forum members working with iodine may give this try and report their observations.
> 
> Randy in Gunnison
> 
> Click to expand...
> 
> 
> Nowhere in this post - the post starting this topic - did Randy mention using "a small amount of hcl". In his third post, Randy was asked if it worked. He replied:
> 
> 
> 
> 
> Just enough to make the water reddish-brown but you can still see through the solution. If the mixture becomes opaque add more water.
> 
> Click to expand...
> 
> 
> Water to reconstitute the iodine.*Water to reconstitute the iodine?!* This is where I changed 'water (H2O)' to 'Hydrogen Peroxide 3% (H2O2)'. This is how to get your "opaque" mixture back to the active reddish-brown it needs to be to work.
> 
> In his 4th post Randy states:
> 
> 
> 
> 
> As the iodine is exhausted tiny bits of metal will fall to the bottom of whatever vessel you would use. There will also be a golden yellow solution left over which still contains gold. I recover most of that on carbon but I am still working on the residue gold left in solution.
> 
> Randy in Gunnison
> 
> Click to expand...
> 
> 
> This is where I got the info on using activated carbon to get my pm values out. I never saw ny 'bits of metal' as Randy described it.
> 
> After several people scrutinize his method (one person even including alohol in thier attempt) and report failures... all of them... Randy reappears and says:
> 
> 
> 
> 
> I am sorry about this but *I forgot to add that I add a small amount of HCl to get the pH slightly acidic. That and iodine water.* And I don't care if it take takes 60 hours -- that is the whole idea of passive stripping. Mix it up and ignore it for awhile. And yet I do do it indoors.
> 
> Randy
> 
> Click to expand...
> 
> 
> Now Randy comes back with this 'oops...'. After my little attempt, Oz informs us that this is now no longer an iodine leach but now an AP solution.
> 
> This thread, at this point IMHO, is irrelevant, costly, and dangerous. It provided partial info that has cost several folks, including myself, time, money, and now possibly my gold.
> 
> If I cant find a viable method in recovering it after ashing and smelting my charcoal I'm going to flag this thread and ask for it to be removed so that other newbies like myself wont be fooled by it, or worse even, be harmed by it.
Click to expand...


----------



## butcher

This seems to me to be an experiment in progress, to work out some details on a process, there is no doubt in my mind that Iodine/Iodide will leach gold and that it can be recovered, there seems to be some differences in how these are oxidized or reduced, many of the forum members are enjoying the experiment, I have not followed every word of this leaching method but I fail to see where you thing anyone is trying to deliberately mislead, I only see them trying to develop it.

Aristo, how would someone prove every work someone said, without redoing that under the same conditions, the moderators here do an excellent job of watch, I cannot think of much anything that gets past their experience or watchful eye, scams and charlatans if they ever miss one usually show up in the light of day. What and why are you asking this of our hardworking moderators?


----------



## Aristo

Greetings Butcher....

The purpose of my comment was to encourage the mods to be more vigilant for the benefit of newcomers and novices with respect to unknown or little known processes . I am sure you are aware of the potential hazards and danger of most of the processes , especially in the hands of novices. 
I do respect and applaud the efforts of the mods, however, there are methods and processes, which have been identified as being beyond the realms of know science, that are touted here by some.
Naivety should not be punished, on the contrary, being misled should be discouraged.
My apologies if anyone was unintentionally offended.


----------



## Astraveller

Yes! This potentially is a very interesting process. One that was used before cyanide became a more viable alternative because it was cheaper. Times have changed. Aristo’s response puts me on ‘amber alert‘! He is well meaning I’m sure but a bit patronizing for certain. 

I would love feedback from people who have knowledge of this process.


----------



## butcher

I have NO experience in the Iodine leach, but if I was to try it I do not believe carbon would be my choice, as I think I would prefer either reduction or a replacement reaction.

My concerns with ashing and burning the Iodine for recovery of gold from the carbon would be the fumes created, and Iodine being a halide whether the gold would volitize with the melt and vapor off in fumes, such as is possible with chlorine gas. Either of these concerns should be easy to determine from a little bit of studying. The iodine will vapor off, that is how it was discovered from burning seaweed, my question would be will it also make the gold volatile in this form?

Ariso, I have no doubt you can recover your gold, the question should be just how to do it.
Gold just will not disappear.

As refiners we are all responsible for our own health and the health of our family and others with these ventures we do, and we are also responsible for doing our own research on the risks and chemistry of reactions we dive into, yes we can take another’s recipe and try it out but we should also research the formula's, dangers and possible reactions or consequences, yes some is done on blind faith but without researching before jumping in we will not know if there is any water under that bridge.

Ariso I believe we all try to make this forum as truthful as possible and that processes posted are proven and in a sense we all MODERATE the forum, I am sure your concerns will be addressed, and I am also sure you will recover your gold, just do not do something you are not sure of.

you have been a member a long time why do we not hear from you very often?


----------



## Aristo

"Ariso, I have no doubt you can recover your gold, the question should be just how to do it."
"and I am also sure you will recover your gold, just do not do something you are not sure of."
Was that being referred to me ?
I made no reference regarding losing gold or not being able to recover gold personally.I have not used the iodide method nor do I plan to.
Your assertions are not accurate. 
Please govern yourself accordingly.

I visit the board from time to time and I try to stay in touch with some members. I try not to get immersed in the actual refining since I handle relatively large volumes of e waste. I usually solicit those who are trained and have the necessary resources and licences to take care of my processing.
I agree with many things that you have written.


----------



## TheGarbageManCan

I have read that Naoh (lye) should drop gold.


----------



## patnor1011

Aristo said:


> I have seen some members of this forum reprimanded, censured or had their priviledge revoked for a variety of reasons ranging from obscene and rude behaviour or to lesser infractions.
> I would ,politely, like to question the moderators as to why the OP has not been reprimaned for apparently leading on falsely or misleading unsuspecting and honest enthusiasts who are simply trying to learn.
> I do believe that there is a wealth of information and experience to be gleaned from this forum, however, there should be some examination of the posts by the "proven experts" prior to its publication or use. In the science of chemistry and metallurgy, there is no magic or as someone put it, witchcraft. Whether it is electronic scrap, ore or related precious metal bearing products, they are all governed by known science.
> I would like to kindly urge those that are responsible to review this matter and, if there are no known scientific proof to what is being presented, some action should follow.
> Thank you.
> 
> 
> DarkspARCS said:
> 
> 
> 
> 
> 
> 
> I thought idea of the use of iodine (at least in this post) was to selectively strip the gold without using strong acids or cyanide, not to dissolve the base metals & leave the gold behind, which every other process described here does, easier & cheaper.
> 
> 
> 
> 
> The thread's title said as much... but it appears the title is misleading!
> 
> 
> 
> 
> An alternative passive stripping system
> by Shecker » September 15th, 2009, 2:27 pm
> 
> I have been experimenting with another passive stripping approach to e-scrap that seems well suited for such things as cpu's, pins, fingers, monolithic capacitors, etc. I've been using a dilute solution of veterinarian grasde Povidine Iodine. I make an iodine solution that has a thin red color (iodine water). This dissolves gold, silver, platinum, palladium, but does not react with lead, tin, aluminum, or copper. As the solution begins to become saturated it starts dropping out some discrete particles of precious metals. It will continue to do until the solution looses it stability and goes clear. I ran some CPU's today and after about two hours the precious metals were laying in the bottom of the container. No precipitation was required. Forum members working with iodine may give this try and report their observations.
> 
> Randy in Gunnison
> 
> Click to expand...
> 
> 
> Nowhere in this post - the post starting this topic - did Randy mention using "a small amount of hcl". In his third post, Randy was asked if it worked. He replied:
> 
> 
> 
> 
> Just enough to make the water reddish-brown but you can still see through the solution. If the mixture becomes opaque add more water.
> 
> Click to expand...
> 
> 
> Water to reconstitute the iodine.*Water to reconstitute the iodine?!* This is where I changed 'water (H2O)' to 'Hydrogen Peroxide 3% (H2O2)'. This is how to get your "opaque" mixture back to the active reddish-brown it needs to be to work.
> 
> In his 4th post Randy states:
> 
> 
> 
> 
> As the iodine is exhausted tiny bits of metal will fall to the bottom of whatever vessel you would use. There will also be a golden yellow solution left over which still contains gold. I recover most of that on carbon but I am still working on the residue gold left in solution.
> 
> Randy in Gunnison
> 
> Click to expand...
> 
> 
> This is where I got the info on using activated carbon to get my pm values out. I never saw ny 'bits of metal' as Randy described it.
> 
> After several people scrutinize his method (one person even including alohol in thier attempt) and report failures... all of them... Randy reappears and says:
> 
> 
> 
> 
> I am sorry about this but *I forgot to add that I add a small amount of HCl to get the pH slightly acidic. That and iodine water.* And I don't care if it take takes 60 hours -- that is the whole idea of passive stripping. Mix it up and ignore it for awhile. And yet I do do it indoors.
> 
> Randy
> 
> Click to expand...
> 
> 
> Now Randy comes back with this 'oops...'. After my little attempt, Oz informs us that this is now no longer an iodine leach but now an AP solution.
> 
> This thread, at this point IMHO, is irrelevant, costly, and dangerous. It provided partial info that has cost several folks, including myself, time, money, and now possibly my gold.
> 
> If I cant find a viable method in recovering it after ashing and smelting my charcoal I'm going to flag this thread and ask for it to be removed so that other newbies like myself wont be fooled by it, or worse even, be harmed by it.
> 
> Click to expand...
Click to expand...




Aristo said:


> "Ariso, I have no doubt you can recover your gold, the question should be just how to do it."
> "and I am also sure you will recover your gold, just do not do something you are not sure of."
> Was that being referred to me ?
> I made no reference regarding losing gold or not being able to recover gold personally.I have not used the iodide method nor do I plan to.
> Your assertions are not accurate.
> Please govern yourself accordingly.
> 
> I visit the board from time to time and I try to stay in touch with some members. I try not to get immersed in the actual refining since I handle relatively large volumes of e waste. I usually solicit those who are trained and have the necessary resources and licences to take care of my processing.
> I agree with many things that you have written.



You contradict yourself. You stated what is marked in red and then when Butcher tried to help you talk about assertions and governing.


----------



## Aristo

The quote in red that you pointed out is a quote from DarkspARCS. Please read carefully.


----------



## DarkspARCS

lol... the part you highlighted in red is a quote to something I said pat...

Anywho, sorry that I havent posted much lately to this thread as I've had a couple of issues come up needing my attention that took me away from this.

I haven't ashed my carbon due to the volatility possibility as well as the loss issue in gold going up in the smoke. I believe that I'm going to have to somehow ash the carbon in a sealed container, however I may also be able to prevent values from being lost in the smoke by just skipping the ashing, grinding my carbon, mixing it with flour, possibly covering the mix heavily with a boron flux (as an added measure to insure loss prevention) and then just smelting it outright, capturing any values within boron glass. I may instead crush up a crt screen and mix my boraxo with the leaded silicate, captuing values in lead and discarding the borosilicate waste.

Regards any values still in the solution (I need to create some stanous and check), I may just let it slowly evaporate though a coffee filter and then smelt any leftover salts with the filter (yes, I have goggles and half-face respirator utilizing chemical filters) mixed with flour and heavily fluxed (just like the carbon) and catch any values in borosilicate glass.

I'm weighing my options. Til then I'm capturing resources to work the next 1000 grams of material with, this time using distilled water and iodine, instead of the copper polluted wter I used with this batch...


----------



## patnor1011

My bad... I need break for a while I guess. :lol:


----------



## donnybrook

Many posts have been made on the various leaching processes which is why I write this, such as the Swan Leach (SSN?),Iodine Leach and the Chlorine Leach.I have looked at and used with success these latter three processes.

I have worked with computer components and mineral sands. The most important thing to do is to remove the base metals. 

With mineral sands from old mine workings using the chlorine leach I roast until the concentrates are red, then remove what base metal I can (such as iron) with a 10% HCL solution using a plastic pale or drum. I filter my concentrates in calico bags and then give this a further roast before the addition of the leach. I found that making my own liquid chlorine using the late Mr Williams method effective producing a stronger form than some of the commercial products sold here. I add this to my concentrate and then adjust my pH to 8.5 using HCL and mix ( agitate) it for one to two days adjusting the pH etc as required. When I believe the leach has done its job I adjust the pH to 7 using Lye and HCL. The precipitate will begin to drop. I have also added SMB when the pH was adjusted to 7.

The SWAN Leach (SSN) using saltwater and nitric and a small amount of iodine was also as effective. After leaching is complete (use an ORP meter) I remove the nitric (expel it) using urea and then precipitate my PM's out using SMB.

Iodine and its use on mineral sands containing PM's is the third most effective method to recover these. I use a 10% solution then add 10 parts water. Adjust the pH to 2 and maintain it during the leaching process. I then filter the solution and mineral sands using a calico filter bag; it should be red brown. Adjust the pH to 7 using Lye and HCL and your precipitate will drop. It could take 1 or 2 days to fully settle on the bottom. Decant or siphon the clear solution off (this contains your iodine) and precipitate (or drop your iodine or iodide) using clorox. Take it up again using Lye ready for use again. There will be some loss of iodine.

I am not a chemist and like others new to the Forum I found many things confusing. I thank the more experienced members on it for their advice at times. Whatever you do or whatever process you use remember your safety using proper protective clothing and known processes. Your health is a priority. If you are not sure get advice as mixtures of chemicals and sometimes admixtures can be disastrous. 

I hope the above helps in some way for those wanting to recover PM"s using these leaching processes.

donnybrook


----------



## dtectr

I, for one, have done even more research & experimentation on this process & I believe that there may have been some holes in cited methodology.
And, I was speaking without understanding when I criticized the use of HCl & H2O2, as their _proper_ use seems to be key for keeping the process working. For that, i apologize.

However, some things I've gleaned:
1. Elemental iodine strips the gold, but only dissolves in sodium/potassium iodide. Elemental iodine is converted to the iodide my dissolution of small amounts of iodine in lye water.
2. As the process proceeds (clears) iodine is converted to an iodide. The leach stalls here. The VERY SMALL addition of HCl converts this back to elemental iodine, and the leach starts up again.
3. The ph is critical, 4-5, small additions of lye water or HCl (monitored by litmus test or ph meter, or orp meter, let you know when. Too much deviation seems to result in at least partial dissolution of base metals.
4. Agitation seems to be extremely helpful, preventing a passivating layer from forming on the objects to be stripped.
5. The -Cl ion is necessary for the leach to work (see #2)
6. Addition of clorox when too much HCl is in solution causes dissolution of precipitate. So, an extended evaporation seems to help "regulate" this balance prior to precipitation.
7. H2O2 can also be used to oxidize the solution, precipitating the iodine - but since all I have is 3%, this results in a considerable increase in volume for me, without measurable success, yet. But, it may sidestep the HCl-Cl dissolution problem

As relatively expensive as iodine is, I'm not sure that this process is the most economical. You are supposed to be able to recover your iodine, but some, at times quite a bit of iodine is lost to evaporation/oxidation/? (I don't know complete cause - these are guesses on my part as to "why").

Butcher - 
You, as well as others, seem to be of the mind, based on your experiences, that the effectiveness of many types of selective stripping/leaching (like Plattner's Process, using chlorine, for example) will be limited/hindered as long as base metals are still present resulting in cementation of values, and this seems to be grounded completely in fact/practice. Much of my limited experience thus far also seems to bear this out. In your opinion, would that factor in with iodine/iodide leaching?

According to the good Dr. from Costa Rica, all the halides, including chlorine & iodine, behave basically the same, with the exception of flourine. Since I'm no chemist, clearly, this sounds perfectly logical. If so, wouldn't the same base metal issue affect the entire group, to varying degrees?

I am very interested in the ongoing nature of this experimentation & welcome any feedback.
dtectr
EDIT: grammar


----------



## butcher

I cannot be much help as this is a halide that I have very little experience with.

From what I understand it is the Tri Iodide that dissolves the gold.
I2 (Iodine) + I- (Iodide) ---> I3 (tri Iodide)
the tri-Iodide (I3) is the oxidant for gold, and with Iodide (I-) forms AuI4,
2 Au + 3 I3 ---> 2 AuI4 + I-
after gold is dissolved ascorbic acid (vitamin C) could be used to precipitate the gold and reduce the Iodine (I2) to Iodide (I-)
this results in a deficiency in tri Iodide (I3), and then the halide is a poor solvent for the gold.
Tri-Iodide has a dark brown color, when tri Iodide is depleted in solution it will turn clear-ish, showing a loss of tri Iodide, and gold will precipitate.

As you stated hydrogen peroxide can be used as an oxidizer for reuse of solution.
Try going to spa and pool supply house for more concentrated H2O2.

Chlorine is more reactive than Iodine in the series of halogens,
Cl2 + NaI ---> 2NaCl + I2
here chlorine is oxidizing Iodide to Iodine

I2 + 2NaOH ---> 2NaI-
here sodium hydroxide is reducing Iodine to Iodide

I cannot understand your loss of Iodine is it as gas or is it locked up with base metals or gangue materials?

As far as base metals since they would also form iodides of these metals, eliminating them only makes sense to me.

Sorry I do not have experience with this leach, and can only go by what I have read, and played with in test tube.
And as you know until you get your hands dirty your not much help.
my hands do not have much to do with Iodine.

Keep up the good work you are helping me, and others to understand this.

edit spell check


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## glondor

I asked about this process in a general way on another forum I used to frequent in the past. http://www.physicsforums.com/showthread.php?t=491186

The inquiry resulted in this link to a patent. Not being a chemist however makes it a bit over my head as far as understanding. Is there any info in this patent that is usable to us?

http://www.freshpatents.com/Recovery-of-gold-from-potassium-iodide-iodine-etching-solution-dt20070920ptan20070217976.php

I am interested in this method for various reasons. I would like to see someone have success with it.


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## dtectr

glondor,
Thanks for your interest & input. The fact that they referred you to the patent without an explanation, sounds to me like they have had similar results to those posted. As I researched, the physics was clear, but the application of it was problematic.

Applying some of butcher's suggestions - i set up 2 test batches, very small, not meant to quantify PM recovery, but to see how easy it would be to control the processes - A) one with a bubbler/screen apparatus in a small glass container; B) another in a small glass container, planning only to use frequent shaking to provide agitation, as some sources suggested.

Results were less than satisfactory on many levels, but did pinpoint some specific problem areas -
*1. Cementation -* B) was clearly worse than A) in this regard, but neither avoided it completely. It even appeared that with B) that the iodine cemented onto the exposed base metals, as well. If this wasn't the actual case, then it must have become trapped in the thick layer of cement. 
*2. Recovery of iodine - *the additions of lye & H2O2 must be in very accurate increments, stochiometric even, for this to work smoothly. 
*3. Process in general -* Also, ph seems to need to be monitored very closely, as I suggested above but wasn't successful in accomplishing without a ph meter.

After reading several related patents using Halides, & my very limited experimenting so far, I believe that if someone had specific knowledge of sites/materials where either iodine or chlorine was used as a leach without the complete removal of base metals first or sophisticated controls, someone with the right set-up & know-how (maybe cyanide?) may be able to extract what was left behind, as I feel strongly that those smaller scale processors were satisfied to get "most of the gold".

If someone is able to do so, please don't forget ol' dtectr when you make some $$$ 8) 

I have other ideas to follow up on, & will try to keep all apprised of my discoveries & ask that all of you following this please do the same.

EDIT: grammar


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## Hamish

Iodine & Gold solubilization & re-precipitation.

After 20yrs of manipulating iodine compounds to generate stable compounds its capacity to get outside the box still amazes me - iodine is not easy to manipulate and requires a solid understanding of the background chemistry that is occuring during use.

While Iodine shares many of the halide properties of Chlorine its single biggest draw is its sensitivity to other competing reactions - you will have upwards of 15 competing reactions present in a vial containing iodine and metals - more if organics are also present - pH amplifies some reactions & supresses others.

Theoretically Iodine provides a range of possibilities - practically controlling/minimizing the multiple side reactions takes time and experience.

Finally the vapours generated from Iodine systems are not to be taken lightly.


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## butcher

Hamish thank you for your post maybe you can help the forum out more about this Iodine leach.


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## Goldfinger4

I found the following (german): http://www.microchemicals.de/technische_infos/gold_aetzen.pdf

They say that a sollution of 4g KI, 1g I and 40ml water can dillute 1 micrometer of gold per minute. The KI does not react but increases the solubility of AuI in water.


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## Hydroxide

Okay. I stumbled upon this forum today as I searched for a refining method utilizing Iodine and peroxides. After reading five pages of posts in this particular thread, I am left with only more questions. 
1) [assumption] there is no literature stating clear balanced reactions/side reactions and steps/reagents because everyone here seems completely ignorant [question] why is there not published research about this so you all don't have to guess and I don't have to work it out for myself a.k.a why no easily accessible knowledge? this is refining METALS. we have done this for thousands of years. what the hell?
2) (kind of relates to 1) why has not a pro inorganic chemist or amateur know-it-all come along and drop their knowledge bombs and lulz directed at us for not knowing/figuring the chemistry out on our own?

Anyone care to take a crack at those- or write a half-worthy method of getting this done...?


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## butcher

Good Idea, can not wait to see it when your done. :lol:


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## Anonymous

Hydroxide said:


> Anyone care to take a crack at those- or write a half-worthy method of getting this done...?


Yeh I will take a crack at solving your problem......and I will solve one more problem for the forum,
Are you "Anders Hoveland"? Can I please get a mod to check his IP? Whether you are or not......you need to learn some respect,or go find your information somewhere else!
You have read 5 pages,on a forum that contains thousands upon thousands,of pages of information,then you have the audacity to redicule us?And STILL ask us to help? You have a lot of nerve,and a lot of unwelcome comments. If I catch you making anymore comments like this again,I WILL make sure that those comments are forwarded to a moderator,and I will ask them to take action.A lot of us have been here for years,trying the best we can to help others for free.Even some of the people that have only been here a few months help as much as they can with the newbies.Noone on this forum deserves,or needs,your insults.


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## stihl88

Hydroxide said:


> Okay. I stumbled upon this forum today as I searched for a refining method utilizing Iodine and peroxides. After reading five pages of posts in this particular thread, I am left with only more questions.
> 1) [assumption] there is no literature stating clear balanced reactions/side reactions and steps/reagents because everyone here seems completely ignorant [question] why is there not published research about this so you all don't have to guess and I don't have to work it out for myself a.k.a why no easily accessible knowledge? this is refining METALS. we have done this for thousands of years. what the hell?
> 2) (kind of relates to 1) why has not a pro inorganic chemist or amateur know-it-all come along and drop their knowledge bombs and lulz directed at us for not knowing/figuring the chemistry out on our own?
> 
> Anyone care to take a crack at those- or write a half-worthy method of getting this done...?



I'll say this politely as i can, go and get stuffed...


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## Harold_V

It appears that this individual made one showing and has not returned. If he does, and runs his mouth, he's gone. Not to worry. 

Harold


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## capt_dugout

evolx10 said:


> Well as with quite a bit of our supplies, http://www.usdoj.gov/ndic/pubs1/1467/index.htm..



this would be a good point to mention the keeping of records.
I try to keep a record of all chemicals in inventory and the amounts used in each of my experiments. At some point we should all expect a visit from our local LEOs due to the ilicit use of many of the chemicals used to refine PMs. 

A little time done on keeping notes could prevent a lot of notes on doing time.


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## DarkspARCS

capt_dugout said:


> evolx10 said:
> 
> 
> 
> Well as with quite a bit of our supplies, http://www.usdoj.gov/ndic/pubs1/1467/index.htm..
> 
> 
> 
> 
> this would be a good point to mention the keeping of records.
> I try to keep a record of all chemicals in inventory and the amounts used in each of my experiments. At some point we should all expect a visit from our local LEOs due to the ilicit use of many of the chemicals used to refine PMs.
> 
> A little time done on keeping notes could prevent a lot of notes on doing time.
Click to expand...


you've brought out an absolute point here with your post, I believe that everyone here - at least in the United States - should begin keeping written records of their chemical inventories, transactions, material usages, and processing techniques in the interest of preserving their own personal legal status with the local Law Enforcement in good standing. If Homeland Security catches wind of your activities and decides to investigate, being labeled as a terrorist by them *IS NO JOKE*!

Having done your record keeping, perhaps an invitation to have a LEO you're familiar with review and record your operation, or even keeping the contact info on government officials whom you have familiarized yourself with and whom you have educated as to your intention and operative results are would go a long way in keeping you off any watch lists.

Unfortunately... American freedom has come to this. These are sensitive times we live in, taking steps to keep yourself protected is your best hope to continue free from any aggression from Law Enforcement - Perhaps an addendum to the welcome message for these forums that includes this type of warning is in order...


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## kjavanb123

Hmm an no conclusing to this post?


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## necromancer

good bump, & good read but................



Code:


i don't see how this went from "alternative passive stripping system" to "Failed Experiment" to 
"Homeland Security investigation" & "being labeled as a terrorist" to "absolutely nothing"


not the climax i was anticipating.


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## prakash2016

Dear all,

Dear All
A Very Good morning to you all.... 

I would like to know whether if there is an alternative chemical to Sodium Cynaide, which is used in stripping gold from cast pieces to give shine below the diamonds before filing???

If yes what is the name of the solution & how that chemicals can be used to strip gold?? Can anybody give full details of the chemicals in full please... 

Can you please guide as I am having a problem of black stones & want to give luster below the diamonds, as processing by the Magnetic polisher does not give the required shine & the jewelry looks dull & life less. 
Someone suggested to use Sodium Cynide, but i am not comfortable with the idea of using it from the point of view of Handling & safety....
Please if anyone can shed light on this issue I will great full. I need a reply for this message ASAP... 
Thanking you
Best regards,
Prakash v Pai
INDIA


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## solar_plasma

When etching a metal as far as I believe to know it will never be left with a shiny surface, but it will be dull. In the case of metals this is definately true for iodine and any acid etchants.

I have read that glass can be etched to have a shiny surface. If this works with metals somehow, it must be special cases, maybe additives, but I am pretty sure, the common leaches will not have that effect. Maybe you should try to find commercial strippers that can do this job.


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## g_axelsson

The procedure is a well known method that at least has been used in jewellery manufacturing. It is called "Bombing" when polishing with cyanide. Some of the gold goes into solution and leaves a finer surface.
http://www.finishing.com/51/98.shtml
And as always... it's been discussed here before.
http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?f=39&t=5443

In fact, chemical polishing of metals is well known in many industries. Also combined as electrochemical methods.

Göran


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## solar_plasma

Yes, Göran, but that is just what he would like to avoid. Can it be done with any other leaches?


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## g_axelsson

I don't know, I just found the old thread and thought it might contain some information.

As this is a question for jewellery manufacturing I would suggest to go to a site like http://ganoksin.com and look for answers from jewellers.
I went there and searched for "bombing" in the archives and got 230 hits. Maybe one of those could be of interest, but I'm not going to read them myself, that's for prakash2016 to do.

Göran


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