# Dissolving tin solder



## samuel-a (Oct 14, 2009)

Basically, i just need a confirmation:

i have this type of processors which ware taken out of different kind of boards:


Scraping them is a real time consuming, plus, still leave some tin, the question is, if HCL treatment will take care only the tin solder, or there is a chance of some gold coming loose to the solution... i know the gold for sure won't dissolve...

will it be more efficient to heat up a bit the HCL ?

Does anyone knows the yield out of this processors ?


Thank you for your answers.

SAMUEL


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## patnor1011 (Oct 14, 2009)

methods of harvesting/refining them are on this forum - they are called flatpacks here so try to search for this word and you will find few methods how to process them.


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## g_axelsson (Oct 14, 2009)

Gold is soluble in molten tin so any gold plated area that is soldered loses the gold. When the tin is dissolved the gold will probably end up as a very fine powder or colloidal solution.
It is the same effect that eats away the copper from the tip of a cheap soldering iron.

In the electronics industry gold contamination of wave soldering baths is a problem and has to be kept under a certain limit or the solder joints gets hard and fragile.

I have always wondered if we are overlooking a source of gold, even circuit boards that doesn't have gold plate could have a certain amount of gold in the solder from a contaminated solder bath. But it probably is just trace levels in the tin.

/Göran


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## samuel-a (Oct 14, 2009)

Thanks again Pantor...

i have done some searching about it, but can't point exactly on my query...

there is alot of information here on the threads... i'm sure, but dou to my lack of knowledge in the professional terminology, i also miss a lot of things...

therefore, the use of search option, though i'm using it before any question, is no help for me....


Thanks again.... 
BTW, it seem's like it's only me and you that are still active here....


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## Anonymous (Oct 14, 2009)

I used to split them in half like you have done. I processed 50 of these of verious types and my yeild was .25 grams of precious metals, the rub is my scale is only accurate to .05 so I my real amount is somewhere between .2 and .3.
It did take me a while to split them but I got a lot faster by time I was in the 30 chips range.

I no long do them that why and I have developed a process/machine that is much faster, uses way less acids, and is being tested right now with 8lbs of chips sent from Glorycloud.

After I have confirmed my process/machine viable, there will be more to follow.

Now as far as dissolving the tin, on the above 50, I use the AP process, but with only 1/4 the normal amount of peroxide, I also diluted the HCL by 1/2 to cover the chips without wasting excess acid. I set this in a warm place and let it go for a few days. The solder was dissolved, but the lead formed pastie little beads and some fluff. This did not cause me much of a problem since the gold foils were very thin and were easily spritzed away from the lead compound. 

Jim


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## patnor1011 (Oct 14, 2009)

hehe...
it is becouse there is midnight here in ireland and I am in the work...
here is what arthur kierski suggest for flatpacks:

for flatpacks this (by my experience)is one of the best ways for gold and pd---ag if and usually is present in the flatspacks one has to put the flatpacks powder in nh40h which will disolve the agcl formed with the acid peroxide--- i am sorry and i am editing my mistake:i use hcl with 30% h2o2,dissolve the gold , filter the solution(containing au and pd) and to the flatpacks powder left i add nh4oh to dissolve the agcl formed.

link:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=5629&hilit=flatpack

and lazersteve:

The standard approach for flatpaks is to crush, shred, or grind the components into a fine powder. Once the material is pulverized you should strip the base metals using nitric acid. 

link:
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=46&t=1145&hilit=flatpack


The remaining material contains the gold and can be leached using any solvent for gold (HCl-Cl, AR, etc.). 

Process the resulting auric chloride solution as usual for the method you select.


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## Palladium (Oct 14, 2009)

Forum book # 2 has links for flat pack processing.


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## samuel-a (Oct 15, 2009)

thank you palladium, but the links are broken....

james, please keep us updated about the procedure... if it works, you can add a Tutorial


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## goldsilverpro (Oct 15, 2009)

I just tried the links and they all work.


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## Palladium (Oct 15, 2009)

You must have the old Phpbb2 copy. Get the updated copy here :arrow: http://goldrefiningforum.com/phpBB3/download/file.php?id=2773


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