Unknown precipitate

[maynman1751]

I know other members have processed this same kind of material the same way that I have. What elements do these components usually consist of? What were they able to reap from their processing?

 

[samuel-a]

maynman1751

This kind of material is somewhat complex to process, especially if you are not sure what to expect.
This raise even bigger difficulties for the inexperienced refiner.

If you read spec sheets of said chips you will learn alot about their possible metalic composition.

Proper incineration is key for effective recovery. If you don't have a fancy industrial incinerator (which most of us don't) you will find that you need to grind and incinrate again.
The organics in those chip package (plastics, epoxy resines etc'...) are packed in layers or one thick layer, your initial incinration may only combust the outer shell of the chip's package and leaving loose carbon inside.
The 1st incineration will eliminate some carbon and all the volatiles, the 2nd grind/incineration will handle the rest of the carbon.
In my mind, it will also be wise to set a fly ash scrubbing, though, in RI 7683 it is reported that no sugnificant amounts of metals were found, let alone PM's.

From my experience, Iron presence is negligible, where the majority of the base metals are copper or copper alloys, Lead and Tin. Pins maybe coated with Ni or Au over Ni which gives them magnetic capabilities and therefore making life easy in terms of seperation by strong magnet.
Those pins are better processed separately from the ground ashes. IMHO.

In terms of PM's presence:
Ag and Au, that much you know.
It is not suprising to find presence of PGM's as well, such as Pd and Pt and even Ru (IV)


Here are the colors of SnCl tests:

False due to Sulfurous acid (exsess SMB):

Take note, that Gold stain is the only one that will not fade after several hours.
testing very dirty (lot's of dissolved base metals) solutions will produce sometimes strange color reactions.


Pd(HDMG)2 drop looks like that:


(Note: it is floating due to the stirrer)

Hope this helps you in some way...
Good luck.

 

[butcher]

samuel-a,
very well done.

 

[maynman1751]

Thanks Sam, nice explanation. I incinerated mine ( maybe improperly) with an oxy/acet torch. Even after completely turning cherry red, I continued to heat them hopefully burning out all of the contaminates. I then did indeed crush them and re-incinerate. I remember reading about carbon being trapped or not being eliminated (I think). The little bits of info that I have found about processing these devices never explained their complexities or perhaps I would have waited until I had more experience. Sam, do you have any input on where to go from here? Thanks, John.

 

[philddreamer]

I was going to make a comment on "incineration", but first, I did a search to find the correct definition before writing & I found the different reasons & ends for WHY we, (who recover & refine PM's), apply heat:

"BURNING - burning, combustion - the act of burning something."

"INCINERATE - (ɪnˈsɪnəˌreɪt)
— vb to burn up COMPLETELY; reduce to ashes.
[C16: from Medieval Latin incinerāre, from Latin in- ² + cinis ashes]
inciner'ation

"PYROLYS is a thermochemical decomposition of organic material at elevated temperatures WITHOUT THE PARTICIPATION OF OXIGEN. It involves the simultaneous change of chemical composition and physical phase, and is irreversible. The word is coined from the Greek-derived elements pyr "fire" and lysis "separating".

"CALCINATION - (kăl'sənā'shən), in metallurgy, process of heating solid material to drive off volatile chemically combined components, e.g., carbon dioxide. It is sometimes a step in the extraction of metals from ores. Calcination is distinguished from drying, in which mechanically held water is driven off by heating, and from roasting, in which a material is heated in the presence of air to oxidize impurities. Originally calcination meant the method of obtaining lime (calcium oxide) from limestone by heating it to drive off carbon dioxide."

"ROAST - In metallurgy, To heat (example: ores) in a furnace in order to dehydrate, purify, or oxidize before smelting, (or digesting, dissolving).

So, I learned something new from this search, & will try to use the proper terminology for the different reasons WHY I apply heat, before or after any given process of material, & the end result for which I used any of the above methods.
(I hope I"m making sense.)

Phil

 

[samuel-a]

Thanks Sam, nice explanation. I incinerated mine ( maybe improperly) with an oxy/acet torch. Even after completely turning cherry red, I continued to heat them hopefully burning out all of the contaminates. I then did indeed crush them and re-incinerate. I remember reading about carbon being trapped or not being eliminated (I think). The little bits of info that I have found about processing these devices never explained their complexities or perhaps I would have waited until I had more experience. Sam, do you have any input on where to go from here? Thanks, John.

I think you should first seperate solids from liquids. Dry the solids and incinirate them.
Then, run them in dilute hot nitric, wash and run them in AR.

With the liquids, try and cement out every thing with Cu slab for few days, notice color changes of solution and SnCl tests until negative.
Remember, you need to provide large surface area of copper when cementing. I'm using a radiator fins made of copper.

 

[maynman1751]

This is the result of the stannous test that I just took.

 

[patnor1011]

First of all is to define what did you burned. crushed, dissolved - I have no idea what is "four legged variety" and what you meant by "smd"
It will be extremely useful if you put here few pictures of material - you can use google image search to show us material you included and you cant photograph because it is crushed...

You did not dissolved much of basic metals by letting them sit in AP for 2 days only. This process need much more time it depend on volume of material involved.
If I will be in your situation I would incinerate everything and use diluted Nitric.