Potassium Iodide-Iodine gold etchant

[pohyh]

Hi All

I am new in this forum and I found that the discussion here is very informative.

I am keen to used Iodine: Potassium Iodide (KI3) etchant to recover gold plated computer/PCB part. I was told that it is very effective but I have not seen any discussion forum on this topic.

Can anyone shed some light on this? I am keen to know the advantages versus other technique, for example, toxicity, gold specificity etc.

Thanks and have a nice day 8)

 

[maltfoudy]

here is some reading on iodine


http://webpages.charter.net/kwilliams00/bcftp/docs/halides.htm

 

[pohyh]

Hi Maltfoudy

Thank you very much for your linformation/ink. I will keep you posted on my finding.

Regards

 

[jadesource]

Maltfoudy as a miner when I first found that site it opened a whole new world of knowledge for me, now I look back and it doesnt seem like much but it shure was good then. He should enjoy that site. Bill

 

[goldsilverpro]

In Firefox, it's amazing how much easier it is to read red on black, or any dark on dark, if you go Edit/Select All. I don't have IE but I think on some versions you have to select with the cursor.

 

[Juan Manuel Arcos Frank]

Pohyh:

Iodine and Bromine are good etchants for gold,but why do not you use the processes that are posted here and work well?.

Manuel

 

[jadesource]

Manual for me when I read about those things i was applying them to gold and PGM ore from mining ,since then I have learned the many problems that arise with halides in those applications and the many other leaching solutions out there . The more i have in my disposal for testing the easier it is to find the proper one for that particular ore body. Bill

 

[qst42know]

In Firefox, it's much easier to read if you go Edit/Select All

That's a good tip GSP! I have a hard time reading red on black text.

 

[pohyh]

Hi Manuel/Jadesource

Thanks for your comment.

I am involved in surplus management of semiconductor industries in Singapore. I have many opportunity to get various kind of chip, contact, platter, target, shield which normally contain some way or the other PM.

Obviously the used of cynide is efficient as gold etchant but unfortunately we in Singapore has very strick environmental protection issue. Although AR is better but the toxic fume from nitric acid is simply too much for people around us not to report to the Ministry of Environment (your equivalent of EPA in USA).

That is the reason why I am keen on halide as gold etchant. From literature, it seem that it is very specific to PM. Futhermore, the gold can be reduce in acidic environment using thiousulfate as reducing agent followed by reducing silver and pallanium in the alkaline environment using for example hydroxyl amine as the reducer.

As Jadesource say it correctly, they are drawback on the halide etchant. Obviously is the cost consideration as the KI and I are expensive. Although the Iodine can be regenerate easily using hydrogen peroxide, regeneration of KI seem to be challenging. If some how the KI can be regenerate, it should be prefect answer to this issue. Perhelp, Jadesource, can you share with us your experience on halide as the etchant.

Although some member talk about replacing KI with hydriodic acid and resolve the cost issue, the hydrazine (staring material) is difficult to find here. Afterall. I have all the necessary chemical to work on KI3 method and I just want to get around to perfect this method (If I can!).

The question I would like to throw to the forum is that is there any suggestion to regenerate KI. My understanding is that some of the base metal is being dissolve in the KI3 etchant and reduce it efficiency. In addition, any input or experience working on this type of halide etcant will be helpful.

Thanks.

 

[Juan Manuel Arcos Frank]

Pohyh:

Let us suppose that I tell you how to make cyanide,how to eatch gold with iodine or how to make KI...Would you share freely your process with all the Forum?...Would you keep all the Forum informed about your progress step by step?.I can tell you but I need you to answer the questions above cited.

Regards.
Manuel

 

[jamthe3]

Wow, c'mon Juan Manuel, given you exchanges on a different thread...this seems like an odd request you're making of the gentleman. If he is the kind that won't, surely he'll answer affirmative anyway to get what he wants; and, if he's the kind that will...the questions are immaterial.

But, as was GSP's...the info is yours to do as you wish. Either way, I always enjoy (and learn from) your posts so hopefully he'll give you the answers you're looking for so I'll benefit from yet another.

Cheers,
John

 

[maltfoudy]

I posted a link for information that was asked for,the reason he wanted to learn about iodine wasn't an issue.unlike mexico nitric costs alot here and any method that can be regenerated has interest to many. including myself,so if he can take what i gave him and come up with a solution to his problem,maybe he can help me with mine. i would much rather spend 400 once on iodine than 100 ten times for nitric.

 

[pohyh]

Hi Manuel

Thank for your feedback and your request.

I am really new in this Forum! Please educate me if I am wrong. I thought I am in this Forum where a group of peoples with common interest come and share their experience on, in this case, gold etching or related subject. With the sharing of our experince, we can cut down the time (for not reinventing the wheel ) or save money (using a more efficient technique). It go without saying, when time come, each and every member, I included, has an obligation to put in writting, telling all those who are keen, on our topic of interest (in my case KI3 etcant).

Anyway, the way you write seems to be a little "hard". Is that the common practise in this Forum? Or it is the way you write? I am a newbie but I took your comment positively.Perhelp the way you put in writting can be refine in the near future
:wink:

Regards

 

[Platdigger]

hahaha, sorry about that pohyh. You just missed all of Manuels ranting
in another thread.
I am sure it is nothing personal, just Manuel trying to make a point.

Point taken Manuel.......

Did you do a search of all the posts on this forum about iodine?
There was a real interesting thread, it was titled something like "you won't believe it! Iodine but with a twist".
Anyway, the general consinses was that it was to dangerous for the average joe to even try.
Randy

 

[pohyh]

Hi Randy

Thank for your comment and indeed you are right, I should have read the comment post by Manuel in the other thread before responding to himl! Anyway as I said, I took the his comment positively and Manuel definately have a pont and he put the strong message right across, I hope, not only to me but to every single member of this Forum.

I studied analytical chemistry and specialised in chromatograhy before going on my own probably 10 years ago to be a surplus management agent for semiconductor industries in Singapore. With that information in mind, I hope you do not have to worry for me on handling of iodine. 8)

Anyway, still look for information on experience on people/member who have work on iodine as etchant. Any infor should be a ++ for me.

Regards
Poh

 

[Juan Manuel Arcos Frank]

Pohyh:

OK,let us do it.Please,chech out if you can get the following,there,in Singapur:

-KI Potassium Iodide
-I2 Iodine metallic
-NH2OH Hydroxylamine
-NaOH Sodium Hydroxide
-H2O2 Hydrogen peroxide (30%)
-Distilled water

The process consists in making a solution of KI and I2 which dissolves the gold layer of e scrap forming soluble complex of K,I and Au then a reductant is added,the gold precipitates and the solution is regenerated.

If you can not get any substance of the list,please,tell me.It would be desirable that you take a look to Steve´s videos about gold contents in e scrap.What kind of scrap do you have?.The process needs 500 gr.,at least,of cutted fingers or gold plated pins or ceramic CPU chips.

Pohyh,I offer you an apology,my english is not good enough and sometimes I think in Spanish trying to write in English.I did not seem too hard.If you are willing to recover gold with KI/I2 I am willing to help you.

Regards
Manuel

 

[Juan Manuel Arcos Frank]

jamthe3:

I do think that Pohyh has experience in Chemistry,since he wrote KI3 (instead of KI)...KI means Potassium Iodide...KI3 is the complex formed with gold in this process...Let us try.

Regards
Manuel

 

[goldsilverpro]

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

I think this patent contains all the chemicals you mentioned and is the source of that method. Go to the EXAMPLE near the end - it tells exactly how to do it.

 

[jamthe3]

Juan,

I wasn't the one talking about the experience or dangers...Heck, I'm scared enough of my own shadow...LOL!!

I was the one teasing you about the requirements for your sharing how to do it; and believe me, that's all it was, good natured teasing.

Estoy poquito tonto y necesito apprender mucho mas....en como hacer oro y como hablar espanol tambien!!!

Salud,
John

 

[pohyh]

Dear Manuel

First of all, thanks for your input and sorry for misunderstanding you on the message you try to put across. Not hard feeling, I take your point positively.

I have got some KI, I, KOH, NH2OH (+dioniser water) from the local supplier. My intention is to play around with ratio of KI:I:H20. I will fixed the I to 1 and H2O to 10 and probably try to vary the ratio of KI from 3 to 6.

Subsequently I will drop a piece of preweighed gold (99.9 around) to a 50 ml of the various ratio of KI3 etchant. When the colour of the KI3 etcant change colour to colourless, I will tke out the gold and weighed them. With that I can find the optimal KI3 etchant rotio.

Obviously the percentage recovery of gold with hydroxylamine (I think I will start with 30% weight: Weight with H20, pH to 8 and buffer with K2PO4) can be determine easily since I know the weight of gold in the KI3 solution.

The 2nd parametr should be the temperature (35 C to 60 C?) may be a good try and least but not last, perhelp ultrasonic sonication may be incoporate later.

Can you comment on the above?

Regards
Poh