What did i do wrong?

[Rreyes097]

So this my serving attempt at processing purple ceramic cpus first attempt I tried 25 various ceramics and it went horribly wrong. Lost a lot on that. But this go round i only did 12 AMDs (the ones with the thin metal heatsinks) and 2 pentium pros.

So I've watched streetips video a million and one times and studied all i could find. Using HCL and hot plate i slowly added nitric until all metal was desolved. Removed from heat. Put in a small cup of ice and water. As per video. Added 2 to 3mls of sulphuric acid to precipitate the lead. But at this point it was late and i just left it in the very cold garage and went to bed after only filtering half of the solution through 2 coffee filters.

Next day continued to filter but felt id not have enough room in the breaker i got second beaker to filter the rest of the solution into. But when I rinsed the beaker containing the ceramics with distilled water it became milky white i didn't see this until its has filtered into second beaker. Fearing the worst i tested first and second beaker with stannous. First beaker was possitive for gold yet the second was not. The second having gold bearing solution plus milky white rinse water. Any advise? Ill attach some pics

 

[butcher]

white powders can from several metals here most likely from lead or even copper I chloride (silver chloride is also a white powder)...

concentrated acidic solutions of some of these metals will hold the salts in solution until water is added, the water not only dilutes the solution, it can also make some of these metals less soluble in solution, copper I chloride, silver chloride, and even tin chlorides can begin to hydrolyze or precipitate when the highly acidic concentrated solution is diluted.

At this point, I would let solution settle (in cold temperatures), overnight if needed, decent solution, filter liquid and eliminated the free nitric acid, the recheck with stannous chloride, and precipitate gold with the reagent of your choice.

 

[geedigity]

With respect to the first breaker containing values and the second one that did not, I think that your values in the second breaker had already cemented back on the tungsten or other metal not dissolved (I think that is what the heat spreader is made of, at least on Pentium Pros). Therefore you probably need to reprocess the second beaker, assuming the second beaker is still mixed with the CPUs.

If you add more water to your 1st breaker, I would not be surprised if it gets cloudy and has to be re-filtered due to the silver chloride that the AR will dissolve and hold in solution. It is not until you dilute that solution and cool it, will a majority of the silver chloride drop out. This has been my experience however.

I will add that when you think you have leached all the gold out of the CPUs, it is not a bad idea to process them again, since reprocessing typically yields a solution containing gold.

 

[Rreyes097]

You said the heatspreaders? They weren't processed with the ceramics. I removed then prior to using AR. So i let solution sit all night in cold temperatures and the white substance settled to the bottom. I think I'm clear now. So i siphoned off the solution and stannous gave a weak yet positive result for gold. Am i missing anything? What should i do with the white stuff? Thanks for the advice thus far. Its always appreciated!

 

[g_axelsson]

Does it dissolve in HCl? Then it's probably CuCl.
If washed and left on a filter paper in the sun, does it turn purple? Then you have silver chloride.
If none of the above tests works then my guess is on tin in some of it's hydroxide or oxide forms.

Göran

 

[kurtak]

As others have already mentioned the "cloudy" precipitate is the result of different "base" metals precipitating out when diluting the solution

This is "common" when processing (ceramic) CPUs by direct AR treatment (instead of dissolving the base metals before AR)

In fact you should absolutely dilute your solution by at least half (dilute 1,000 ml concentrated AR with 1,000 ml water) so that it does precipitate out those base metal salts --- dilute the concentrate AR - then let it sit for at least 24 hours to settle out the BM salts - siphon of the majority of the clear (after settling) solution & then filter wash the sludge "good" to get all the AR out of the sludge - add the filter/wash water back to your dilute solution - if it clouds again - repeat settling - decant/siphon etc. until it no longer clouds

Depending on how much you end up diluting to get a clear solution you may or may not want/need to evaporate the solution back down before precipitating the gold

If you do not follow the above instructions to precipitate out the BM salts first it will result in them precipitating out "anytime" you add water when trying to precipitate out the gold which in turn will result in "very" contaminated gold

As it is - your first drop (of gold) from CPUs processed by direct AR is going to be contaminated - but if you get rid of as much as possible of the problem BMs by diluting you will have less contaminated gold when you drop the gold - which in turn means less problems cleaning the gold up after it is dropped

Kurt

 

[kurtak]

So this my serving attempt at processing purple ceramic cpus first attempt I tried 25 various ceramics and it went horribly wrong. Lost a lot on that.

Per the underlined -not sure what you mean by "Lost a lot on that --- but you never "loose" gold - its just a question of where it is & how to recover it --- its only "lost" if you throw it away

Figuring out where it went & why & then who to get it back is often the hard part for the beginner (& it happens to all of us when first starting out) presenting your problem &/or asking question is what we are here for

So - unless you actually threw everything away (other then the gold you did recover) tell us what you did - what you have & we can most likely help you get what you think you lost

Kurt