Processing Au/Ni CERDIP IC's?

[Brett Novak]

Hi Folks

1st let me say thanks for the wealth of information and intelligence of the community, and the shared resources.

So this one has me stumped, and maybe I'm just too dumb with a search engine, but, I have BUCKETS (40 to 50#'s worth) of gold-over-nickel ceramic dual inline package IC's. These also have interior gold bond wires.

They look like this

And have a gold-over-nickel cap on top. (I pulled the ancient MSDS / Package drawing to figure out the base metal. )

Now - I have read post after post about "cooking" the devices first and then crushing, but I don't think that's necessary in this case as the metals are NOT completely encapsulated once the cap is dissolved off.

But - my concern is that there is a huge % of the dissolved solution containing Nickel, which SMB precipitates out of AR along with Gold. Is there something I should use before SMB for gold to get the Nickel content down? Or rather than AR dissolving, go to a plating removal process instead (with AP or similar?)

First batch I was able to precipitate a nice brown foam that has been drying out for a bit now. I may have messed up and got into the spinning loop of death with excess NO2 as I had to use a LOT of SMB, but we'll see how that ends up. I did DeNox with Urea (I tried using BluDEF, maybe that's the issue) and never got any "black gold" precipitate but plenty of brown muck

So - I'm open for ideas. Thanks in advance and cheers!

 

[orvi]

You have the best material for processing. Very high gold content compared to overall metal content.

Easy work. If the lids on top of ICs are all metallic (gold or not, but metal), you can just dump all of it into the AR and let it react and sit for several days to properly dissolve all of the gold bearing solder from under silicon die. If they have ceramic lids, or they are varnished, you will need to crush them for the acid to get to the brazed ceramics and silicon die in the center. Then proceed as usual, SMB won´t drop any nickel, just gold. De-nox with combination of sulfamic acid and copper, which cause the gold to cement from the solution completely - if you heat the solution to near boiling temperature and wait for the reaction to end and gold to pack to nice coagulated precipitate. Collect the gold and re-refine. You are done

 

[Brett Novak]

Thanks Orvi! My first run, I can for certain say that lids are metal and dissolved completely. Cap, leads, bond wires, everything - gone - Except for the silicon die and the sticker on the top

Picking up some Sulfamic Acid on the way home from the office today. Have plenty of copper wire, pipe and even refined pure copper from other melting projects.

Now it's just waiting for the FedEx truck with my Nitric acid

Cheers!

 

[orvi]

Thanks Orvi! My first run, I can for certain say that lids are metal and dissolved completely. Cap, leads, bond wires, everything - gone - Except for the silicon die and the sticker on the top

Picking up some Sulfamic Acid on the way home from the office today. Have plenty of copper wire, pipe and even refined pure copper from other melting projects.

Now it's just waiting for the FedEx truck with my Nitric acid

Cheers!

I described AR dissolution to fair depth in many of my posts, just search them in the forum using search engine, chosing my nickname for the replies. Key is to not overshoot nitric and keep the pot with AR very hot as long as possible. Add all needed HCl and dose calculated nitric by 1/3 increments. And first, heat up HCl to at least 45°C, otherwise onset of the reaction would take ages. Don´t add more than 1/3 of expected nitric, otherwise you will get a runaway reaction. Good technique is to let the container sit, well insulated overnight - retaining heat keeps the reaction somewhat going. In the morning you can check the stuff - if it is dissolved or there is good portion of undissolved stuff. Then you either add fresh dose of nitric and heat again to sustain a reaction, or decant, rinse and proceed to denox and drop.

 

[Lino1406]

Hi Folks

1st let me say thanks for the wealth of information and intelligence of the community, and the shared resources.

So this one has me stumped, and maybe I'm just too dumb with a search engine, but, I have BUCKETS (40 to 50#'s worth) of gold-over-nickel ceramic dual inline package IC's. These also have interior gold bond wires.

They look like this

And have a gold-over-nickel cap on top. (I pulled the ancient MSDS / Package drawing to figure out the base metal. )

Now - I have read post after post about "cooking" the devices first and then crushing, but I don't think that's necessary in this case as the metals are NOT completely encapsulated once the cap is dissolved off.

But - my concern is that there is a huge % of the dissolved solution containing Nickel, which SMB precipitates out of AR along with Gold. Is there something I should use before SMB for gold to get the Nickel content down? Or rather than AR dissolving, go to a plating removal process instead (with AP or similar?)

First batch I was able to precipitate a nice brown foam that has been drying out for a bit now. I may have messed up and got into the spinning loop of death with excess NO2 as I had to use a LOT of SMB, but we'll see how that ends up. I did DeNox with Urea (I tried using BluDEF, maybe that's the issue) and never got any "black gold" precipitate but plenty of brown muck

So - I'm open for ideas. Thanks in advance and cheers!

The outside color does not look like gold, more like beryllium copper, or carbide

 

[Brett Novak]

Lino - that was just a stock photo I grabbed from online. The ones I have are gold plated nickel.

Orvi - thanks again. Good tip on the heat and insulate, and yes - I learned the hard way not to premix the AR (yes, I had a runaway foam over)

I have an old cooler that I can use to keep it warm - shouldn't be hard as our nighttime temps only get down to 30C this time of year

thanks again guys! I'll get some pictures this weekend.

 

[Brett Novak]

Hooray! 1st run went great. 2x 1000mL beakers with 100g of IC's in each. Yielded 2.5grams in a button.

But 2nd run not so good. Rather than black particulate at SMB stage, I ended up with quite a bit of orang/yellowish "mud" for lack of a better term.

Same process - put IC's in beaker - add distilled water to halfway covering them, then HCL to cover. Add to heat, to a simmer, and drip in Nitric. Simmer for an hour or two, remove from heat, stanous check, pack it into warm cooler for the night. Then add some Sulfamic Acid (dry) to DeNox.

Precipitate with SMB, and let it sit overnight again.

Is that stuff refineable? Just keep washing it? or re-run it through an AR cycle? Nice clear green liquid on top and negative stannous tests.

I'm stumped, but thanks for all the knowledge so far guys!

EDIT: Oh crap - should I re-heat the solution BEFORE adding SMB? Or perhaps BEFORE adding the Sulfamic Acid?

 

[Yggdrasil]

Hooray! 1st run went great. 2x 1000mL beakers with 100g of IC's in each. Yielded 2.5grams in a button.

But 2nd run not so good. Rather than black particulate at SMB stage, I ended up with quite a bit of orang/yellowish "mud" for lack of a better term.

Is that stuff refineable? Just keep washing it? or re-run it through an AR cycle? Nice clear green liquid on top and negative stannous tests.

I'm stumped, but thanks for all the knowledge so far guys!

If you get black powder after SMB it may be dirty Gold.
Clean Gold look like Cinnamon.

 

[Brett Novak]

Picture this time. And yeah - I think I goobered up the temperatures when I added sulfamic

 

[eaglekeeper]

This would be considered the "recovery" stage. If your solution was heavily contaminated with base metals, some times the gold powder will be dark. That's why you'll have to refine the powder to get it clearer.

 

[Brett Novak]

Dave - sorry to sound stupid, but by "refine" at this point, are you saying another run of the AR type solution? Or HCL/H2O wash cycles? Or, but it under the torch and solidify it?

 

[Yggdrasil]

Dave - sorry to sound stupid, but by "refine" at this point, are you saying another run of the AR type solution? Or HCL/H2O wash cycles? Or, but it under the torch and solidify it?

Dissolve it again in a minimum of liquid and drop it a second time.
It will remove practically all contaminants and leave you with 99.9 + plus Gold

 

[Brett Novak]

Gotcah - thank you sir!

I've been catching all of this - good thing I guess - since I probably have 2 gallons of it now!

 

[orvi]

Hooray! 1st run went great. 2x 1000mL beakers with 100g of IC's in each. Yielded 2.5grams in a button.

But 2nd run not so good. Rather than black particulate at SMB stage, I ended up with quite a bit of orang/yellowish "mud" for lack of a better term.

Same process - put IC's in beaker - add distilled water to halfway covering them, then HCL to cover. Add to heat, to a simmer, and drip in Nitric. Simmer for an hour or two, remove from heat, stanous check, pack it into warm cooler for the night. Then add some Sulfamic Acid (dry) to DeNox.

Precipitate with SMB, and let it sit overnight again.

Is that stuff refineable? Just keep washing it? or re-run it through an AR cycle? Nice clear green liquid on top and negative stannous tests.

I'm stumped, but thanks for all the knowledge so far guys!

EDIT: Oh crap - should I re-heat the solution BEFORE adding SMB? Or perhaps BEFORE adding the Sulfamic Acid?

Yellow/orange mud can be caused by low acidity of solution - iron will precipitate out. Add more HCl and observe if the goo will re-dissolve back.

 

[Brett Novak]

Will do - thanks Guys - guess I need to pick up more HCL on the way home

 

[Brett Novak]

not bad for my first run at this.

~8kg of stock, triple AR refined. 4.13Oz (standard NOT troy)