ceramic cpu succes / kovar problem

[bogarasjoe]

Mi first gold buttons are here . I am very happy! Thanks for everybody who helped for me. Especially, so much thanks for Goldsilverpro! Chris, you gave me some very useful advices! Thank you for Irons too for interesting informations and ecouragement! Thank you for Sam too, you have a very nice homepage,your instructions on www.goldnscrap.com are very very useful!
About the process:
I removed lids with a gas torch. Than I crashed the ceramics and soaked in AP (smaller button) / hot nitric acid (bigger one). Than I used poor mans AR! So ceramics were heated in HCl and NaNO3 added while reaction occured. Tested with SnCl2. It became purple, and darker and darker. When the reaction finished, it was allowed to cool, than sulphuric acid added and poured to ice. Left for about one hour, than filtered.
I added some sodium metabisulfite, left settle for one day. I decanted it carefully with a syringe and washed sometimes. Gentle heated to dryness.
Than I drilled a hole on a piece of grilling charcoal. I heated it up, than added some borax. I heated once again and added gold powder. Than melted carefully. It was done with a simple PB torch and it was working quiet well! Yield was about 0,3 g (from 8 CPUs).
Than I tried to get gold from kovar (is it kovar too on ceramic cpus??)lids. I boiled them in HCl for 3 hours. The lids didn't dissolve very well, there wasn't floating any gold foils. Weight was 10 g before and 5 g after boiling in HCl. Washed several times with water. Than boiled in hot nitric acid for a few hours. It was a so virgous reaction, some foils floated (but not all of them). Tested with a magnet, they were still magnetic . Boiled once again in dilute nitric. After boiling and filtering HCl / Cl added. Left for a day. SnCl2 tested positive. Left for some more days. SnCl2 tested again, and I can say it became negative. So I think there left so much base metals, and gold crystallized back to kovar (. It is so said for me. But gold is still here and waiting for me !

Regards, Dave!

 

[bogarasjoe]

Sorry of my english! Of course I wanted to write kovar legs (not lids). I removed metallic lids too from the bottom and collected separately.

 

[butcher]

I had no problem understanding your English, I wish I could speak another language that well.

Dave keep at it, you will get that gold that is waiting for you.

 

[samuel-a]

Looking good so far, Dave.

It is this kind of experiencing that teaches us the most.

I'm pretty sure, as you said, there's a bit more gold you can recover from this process. Just don't throw anything yet 8)


The only comment i have is the melting, It seems you didn't got hot enough to bring the metal to fully melt and i doubt you can achieve that with pb torch, also, do not melt in charcoal, it has impurities and it burns away. Clay crucible are a dime a dozen and will serve you well.

 

[bogarasjoe]

Thank you boys so much ).
Gold is still here, it was waiting for me. And looks pretty )

After boiling kovar legs once again in HCl, itt dissolved so fast in aqua regia (just 5 ml HCl added, than nitric drop bye drop, until all the metals dissolved). SnCl2 test was black. H2SO4 added, poured on ice, filtered and precipitated with SMB.

You was absolutely right about melting Sam, it didn't melt perfectly (the newer one seemes better). I melted the nwe one on graphite. It would be so much better with an "oxy" set, but I don't have it yet .

Regards, Dave