CPU collection lot

[Palladium]

Maybe this was just an experiment I don't know but I would recommend precipitating your gold in a beaker instead of a flask. You should dry your gold in the beaker it was precipitated in instead of washing it into a filter where some will be trapped and lost until later recovery when the filters are processed.

 

[kjavanb123]

even though your using peroxide, im not sure the method your using it can be described as AP. though technically it is, not many members use peroxide with the express intent of dissolving gold. 25% peroxide will definitely do the job, but i have to warn you. heating hydrogen peroxide that is that concentrated is playing with explosives, literally. the fumes can decompose violently.if its working for you and you dont mind the risk then who am i to complain.

Geo,

I have a glass on top of the beaker as soon as I add the 25% h202 to it in 10ml, so most of the fumes are back into the solution. But this avoid dealing with nitric and drop of gold from this method was instant and fast.

Thanks for your help on this experiment.

Kevin

 

[kjavanb123]

It a shame i haven't seen this post earlier...

Kev,
You have learnd the painfull lesson of too much nitric in you AR. With the risk of sounding like an old p****, had you followed the strict regime in regards to nitric addition, non of this would have happend.
You have done great by sharing your process and observations, I hope your experience will also help someone else trying this for the first time.

With that said, there are few solutions to such kind of a mess, here are the two i have found to be most effective in such case:
Urea would be my no. 1 choice - yes, i know it's not so popular around here, but Urea is a great tool to have when you mess up. Since the solution is so diluted, but still dissolving precipitated gold, i makes little sanse to try and evaporate it.
To kill free nitric with urea, warm up the solution, just warm to the touch, say 85-93F. Add few prills of urea and observ how do they react with the solution, meaning, is it very rapid? does it fizz like crazy or calmly... this will somewhat help to approximate if you have planty of free nitric or just a little.
If you have found that indeed an excess of nitric is present, add the urea prills incrementally and in a decreasing manner at each addition. Mix well between each additions until there's no more fizzing and the prills are slow to dissolve.
After that treatment, precipitation should be proceeded with no special events.

Another method, would be to simply warm up the solution to 158-176F and pour in a solution of warm water + SMB and letting the AR to re-dissolve the newly precipitated gold. Repeat that process until the gold does not re-dissolve. Add constant stirring if possible.
It is similar to Harold's and Geo's suggestion from earlier in this thread, the only diffence would be that instead of adding gold from an outside source to consume the nitric, you are consuming it with the same gold over and over again.
This may be time consuming either way, but with this method, you get huge surface area to react with the dilute AR, so it will probably be quicker.
A gold bottom is great for when the AR is concentrated. IMHO.

To conclude, i hope this experience will not discourage you from attampting this process again for ceramic cpu's, as it is fast and cheap.
By now, with the help of the members here, i'm sure you know what to avoid and how to handle yourself if things head south.

Good luck with your next project.
Sam

Sam,

I really have to thank you because if it wasn't for your video of processing old CPUs I wouldn't even start this. So thanks for sparking the idea in my brain :lol:
In regards to your suggestions, I have saved the solution that was messed up and it is still positive for gold, but got 2 grams of it already dried and purified. As you can see from the picture below,


I am going to follow your first suggestion and post the result, hopefully someone else might actually avoid the mistakes I made.

Thanks again all,
Kevin

 

[kjavanb123]

Hi,

Second batch consists of 5 intel pentium MMX which were dissolved in Hcl and hydrogen peroxide after filtering and dropping silver compound from the solution, filtered it, dropped SMB to the solution first spoonful didn't produce any brown foams but second addition of SMB produced some brownish foams, what that could be?

Thanks
Kevin

 

[philddreamer]

Kevin, why are you adding SMB to the AP solution? Did it test positive for gold? AP doesn't hold gold in solution because it usually is saturated with base metals, copper in particular. Also, silver dissolved in AP!?

Phil

 

[kjavanb123]

Phil,

I had no idea about AP or AR leach would require different agent to drop the gold, so I just used SMB. what else should i have used for AP leach? I checked the solution and is negative for gold, but the brownish fine powder is at the bottom which i have to purify today and post pictures.

Thanks and regards,
Kevin

 

[philddreamer]

Hi Kevin!

what else should i have used for AP leach?

Clean copper!
As we have mentioned before, gold doesn't stay dissolved in an AP solution because the AP is saturated with copper & gold WILL NOT stay in solution; it will cement. Unless you add too much peroxide AFTER all the copper has dissolved, the excess of peroxide will dissolve some of the gold foils, then maybe some gold will be in the AP solution. Testing with Stannous Cl will reveal if there's any present; then you will just add some more copper, thus cementing the gold.
AP is mainly a process for recovering gold. AR is more for refining the gold.

I checked the solution and is negative for gold, but the brownish fine powder is at the bottom which i have to purify today and post pictures.

Yes, the solution will very likely test negative; the gold will be the dark sediment at the bottom. This will be refined for higher purity. This is when you'll be adding SMB. (You could add copper to cement the gold, but that's not adviced when you are REFINING.)

You should re-read the instructions on AP (& also AR), so you you can pick up more details of the processess & have less troubles on next batches.

Kindly, 8)

Phil

 

[kjavanb123]

Phil,

Interesting enough, the last purified brown gold powder you see in the picture, was produced by re-dissolving the powder in AP, after being washed with water and ammonia and hcl 3 times, and dropped by adding SMB, I even checked the remaining solution from that and it was negative for gold.

So you are saying I should just stick a copper wire into the current AP gold solution to collect the remaining gold?

Thanks and regards,
Kevin Jones

 

[lazersteve]

Phil,

Interesting enough, the last purified brown gold powder you see in the picture, was produced by re-dissolving the powder in AP, after being washed with water and ammonia and hcl 3 times, and dropped by adding SMB, I even checked the remaining solution from that and it was negative for gold.

So you are saying I should just stick a copper wire into the current AP gold solution to collect the remaining gold?

Thanks and regards,
Kevin Jones

Kevin,

Acid Peroxide has several uses as you well know.

One use is to use it to dissolve the bulk of the copper from escrap to release the gold foils from the scrap. When used in this manner sometimes a little gold gets dissolved in to the solution. Simply add more copper to cement out the traces of gold from the high copper concentration solution. The gold will be a dirty black color and need to be refined a second time to bring it's purity up to par.

The second application of Acid Peroxide is to dissolve the foils and gold powder for the second refining. In this instance the gold is mostly pure and free of base metals so it is best to precipitate the dissolved gold using SMB or copperas. Using copper to cement the gold in this instance actually works to contaminate your gold again with the copper you are using to cement. This defeats the purpose of refining the gold and is counter productive.

I hope this clears up the multiple uses of AP and the means by which dissolved gold is recovered from the various solutions.

Steve

 

[kjavanb123]

Steve,

Thanks as always for being such a help. I figure out for my next batch which is going to be 12 VIA gold lid chips I remove most of the base metals with a nitric leach, wash and decant with water, then proceed with AP leach in order to avoid getting involved with excessive nitric, that way I can drop all the gold using SMB.

Here are some latest photos of discussed project.

Gold powder being dissolved in AP, without heat, then filtered and ready to be dropped using SMB.


Few seconds after addition of SMB to the above solution


Few mins later after addition of SMB to the gold AP solution


Also during the purifying process for gold powder, in section of addition of ammonia and heat, the following residue was produced which i decant in a different jar, it had a layer of brownish cloud right in the middle of solution, so i added hcl to it and all the brown stuff disappeared, how can i know if this was silver?


Regarding the Intel Pentium 486 DX series project, which the solution even after addition of excessive amount of SMB tested positive for gold, I dropped in an iron rod, and after a week this following residue is filtered and solution tested negative for gold, so I assume this iron rod took down any gold in the solution with it, so I need to purify this mix. Please advise.

 

[samuel-a]

so I need to purify this mix. Please advise.

Kev, if you think there's gold in this sludge, proceed as follows:
Dry
Incinirate
Digest with dilute nitric (test the leach for silver with HCl)

The undissolved solids will be gold and some left over ashes. Then dissolve the gold with whatever leach you are comfortable with.

 

[maynman1751]

Regarding the Intel Pentium 486 DX series project, which the solution even after addition of excessive amount of SMB tested positive for gold, I dropped in an iron rod, and after a week this following residue is filtered and solution tested negative for gold, so I assume this iron rod took down any gold in the solution with it, so I need to purify this mix. Please advise.

THis is where you should be using copper to cement-not iron. By using iron you also dropped out the copper. If you had used copper, only your values would drop (plus some dragged down contaminants). Your sediment would be much 'cleaner' and easier to clean up and a lot less of it. Your way will still work, but adds a lot more base metals to the mix.

 

[lazersteve]

A note of caution using highly reactive metals to clear left over acidic solutions of SMB and SO2:

If you do not heat the solution to drive out any excess SO2 present before cementing, there is a very high probability of forming the deadly gas H2S (hydrogen sulfide). The gas smells of rotten eggs (50% of the population can't even smell it) and is as deadly as hydrogen cyanide. The gas is formed when sulfurous acid (SO2 with acid in water) is combined with a metal higher than hydrogen in the activity series (iron, aluminum, zinc, tin, etc). Check my website documents for information on sulfurous acid and the activity chart.

For the above mentioned reasons perform this reaction in a good fume hood or in a very well ventilated area.

The brown sludge is a mixture of base metals and their sulfides formed by the in situ reaction of sodium and hydrogen sulfides from the excess SMB solution and the iron you added. This is also the cause of the false positive (brown) reaction one gets when testing a strongly sulfurous solution with stannous chloride. Incinerating the brown solids will produce a strong sulfur odor and other toxic sulfur gases. Adding acid directly to the brown solids will also regenerate the H2S.

Please read the entire wiki article on hydrogen sulfide and the above referenced documents from my website.

Steve

 

[kjavanb123]

All,

Thanks for your input on the copper / iron incineration process, i filtered the black residue poured it in a flask, and dropped in some dilute nitric to it as u can see in the picture below,


But some residue is still undissolved, should i try dissolve them with sulfuric or hcl??

Best regards,
Kevin

 

[kjavanb123]

Just one more thing, I got another lot coming up containing 12 pieces of VIR gold lid cpus and 3 IBM gold lid chips, and I don't wanna mess up, so I am gonna follow the following instruction which will be a brief of what I learned from this project and post.

1. Try to expose as much as areas of visible gold wires or foils by crushing the CPUs
2. Dissolve most base metals in a nitric leach.
3. Wash and decant with water
4. Pour the nitric solution into a beaker with ice in it to bring the solution temperature down and add sulfuric acid to allow any lead or silver to be
dropped out of solution.
5. Dissolve the remaining CPUs in AP, in order to avoid nitric, then filter, and check for any remaining gold signs on CPUs, then drop with SMB.
6. Purify if needed, dry.

Thanks and regards,
Kevin

 

[kjavanb123]

All,

I followed your advise, and dried the undissolved section of solution of the brown mud in previous picture, after I added dilute nitric, but strange enough, I tested the greenish solution and it was positive for gold?!?!?! yet there are some undissolved residue at the bottom. This is really strange.

Here are the picture of solution after I added some nitric to it boiled it for few minutes.


And this is the stannous test result of the same greenish solution above.


I am going to remove any excessive nitric using the Urea methods mentioned here in the post, and try dropping the gold with SMB.

Thanks
Kevin

 

[maynman1751]

A note of caution using highly reactive metals to clear left over acidic solutions of SMB and SO2:

Steve! Wouldn't the SO2 have left the solution after a week of setting? Was I correct in telling him to use copper in that instance instead of iron? Thanks, John.

 

[kjavanb123]

All,

After heating the saturated SMB solution which showed positive for gold yet not precipitated, I added Urea in small increments, got fizzing, till no more fizzing, then I added SMB into the solution and solution turned from green color to this light brown color as following


and closer shot,


So I am gonna wait till it settles, and also solution showed no signs of gold.

Keep you all posted
Regards,
Kevin

 

[lazersteve]

...

Steve! Wouldn't the SO2 have left the solution after a week of setting? Was I correct in telling him to use copper in that instance instead of iron? Thanks, John.

Not always the case. The solution itself will hold some free SO2 depending on many factors including dilution, pH, temperature, container geometry, etc.

As for using copper or iron, I always use copper to recover traces of values from my stock solutions that test positive with stannous chloride. After recovering the values via filtration, I follow the copper cementation procedure with a treatment of metallic scrap iron to recover the copper. The remaining solution is then filtered free of copper and neutralized with base for proper disposal.

Steve

 

[kjavanb123]

All,

3 pieces of IBM gold lid chips was dropped into nitric and boiled for 15 mins to remove the base metal, the indicating sign that nitric has dissolved all the base metals would be after addition of fresh nitric to solution, I get no more brown fumes, then i am gonna decant, wash with water, decant, and continue till after water addition doesn't change color. Pour the nitric solution into an iced beaker, drop some sulfuric to drop any remaining silver or lead sulfate.
AP the remaining CPUs and proceed with SMB.

Pictures are coming up.

Regards,
Kevin