Processing ICs with nitric

[kjavanb123]

All,

These were the ICs scrapped from PCBs of keyboards I smashed to get the mylars, its total weight is 78 grams ( 0.17 lbs ) you can see photos in my mylar processing post. I put them into the shredder we have in the facility and produced the following output;


I put them in the beaker, and added dilute nitric acid ( 50 by 50 nitric acid and distilled water ),


After few mins the reaction started and tin, copper started to dissolve as you can see from the color of solution,


Next step would be dilute the solution by adding some distilled water, decant, rinse well, decant, then adding dilute sulfuric acid ( 50/50 sulfuric and water ), to the meta stannic acid ( tin paste ), this will remove the nitric left from previous process, so then dissolve the gold in AR, filter, rinse, filter, drop with SMB.

Will post result with photos.

Regards,
Kevin

 

[Pantherlikher]

I'm not sure so asking.... How did you remove the problem tin?... Doesn't it make things problematic?...
Again, I have N)OT read up enough on it but thinking HCl soak/bath would rid the tin before AR...

Or mayby?
Start with warm HCl, then AP then Nitric and finally AR?
Ridding the easier metals before moving on?... The Nitric after AP would get any possible Silver out before AR for Gold.

B.S.
...If I don't ask it, it's a stupid question...

 

[kjavanb123]

Panther,

According to CM Hook on page 79, the tin paste will dissolve in 50/50 sulfuric acid and water, some heat, then you empty the mess into a large vessel of water, then filter, rinse, process the remain with AR.

Hope that answered your question.

Regards,
Kevin

 

[Pantherlikher]

Excelent...thanks
Goes to show my memmory is the first thing to fail...

 

[Geo]

im afraid you will not be able to reclaim a large percentage of your gold the way the material looks now. the bonding wires are so tiny that even the smallest piece of plastic will hide many. the typical bonding wire is about 10 times as small as a human hair. there seems to be quite a bit of material that i dont normally have in mine (like wires and the small round piece). you might try to find a small camp wood stove and put a wood fire inside. when the wood is on fire good, add you crushed material to it. the wood will burn any smoke as long as you dont feed it in too fast.

 

[kjavanb123]

This is the thread where they talk about processing ICs without incineration,
http://goldrefiningforum.com/phpBB3/viewtopic.php?f=37&t=17591

Discussion there seems to be incomplete, so I am trying to follow this method.

Regards,
Kevin

 

[Marcel]

<80g is by far too few to expect any visible output.
Also I would have suggested a pretreatment to remove BMs other than dilute nitric.
Legs should have been removed etc, etc....