CPU collection lot

[Palladium]

Do you have a gold button to add to consume any free nitric?

 

[Geo]

well, for sure its still got free nitric and also for sure its still positive for gold. you can evaporate the solution till it forms gold crystals. ive seen pictures on the forum of dry gold chloride. Hoke says to evaporate until the solution is very thick like syrup. then you will add hcl to re-hydrate it and then evaporate again. each time, it expels nitrogen dioxide. Harold would recommend adding a small gold button to the solution and warm it. you would wait until the reaction stops or the gold is consumed. either way may be something you have to consider because you obviously have used way too much nitric.

 

[kjavanb123]

Geo,

Thanks for your advise. The solution is now 1500ml, I tried steam bath it for almost an hr and only gray fumes comes out. In case I want to drop a gold button, can I use something else like copper rod it will consume some excessive nitric. Please kindly advise.

Also, at this point addition of copperas will help? I know my SMB is old and clumped up together.

Thanks and regards,
Kevin

 

[Harold_V]

Geo,

Thanks for your advise. The solution is now 1500ml, I tried steam bath it for almost an hr and only gray fumes comes out.

That's exactly as it should be. There's a considerable amount of water in your solution which must be eliminated before you can expel the unused nitric. If the vapor cloud coming off has any color, that would be an indication that you are evaporating too quickly. When the solution is condensed enough, it will become thick like a syrup, at which time you'd introduce some HCl. That expels some of the nitric, which you'd see as the familiar brown cloud.

In case I want to drop a gold button, can I use something else like copper rod it will consume some excessive nitric. Please kindly advise.

Absolutely not! The only thing you should add to the solution if you hope to consume the free nitric would be more gold. If you use a base metal, it will cement gold. That, too, would work, but it requires a perfect balance of base metal, so that the small amount of gold that would be cemented would then, in turn, be dissolved by the free nitric. Hitting the proper balance isn't likely, so don't go that route. Besides, you'd be introducing base metals to your solution that are in direct conflict with your objective, that of purifying the gold. Use a piece of gold, or evaporate properly. Both work well, and should be understood by you.

Also, at this point addition of copperas will help? I know my SMB is old and clumped up together.

I can't address your clumped SMB, but I used copperas in refining, although I preferred SO2 gas. Copperas is a good choice if you have any doubts.

Harold

 

[kjavanb123]

Harold,

Thanks much for your input. I read some archived articles on the forum, and there was a suggestion to dissolve a tablespoon of SMB to 50ml of hot water and pour that to the solution. I just did that and just fizzling no more brown fumes or foams formed. I just gonna wait for another 24hrs test the solution for gold with stannous.

Thanks again for all your help
Kevin

 

[kjavanb123]

All,

Thanks for your advices. I finally resort to zinc addition to the AR solution. I remembered when pushing the mixed PGM powders from the AR solution we used zinc. So I tried this with gold in AR and since I tried to rinse the remaining brownish powder with HCL and got no reaction I could guess this is the gold powder stuck in AR solution which I had issues dropping it with SMB.

Here are some photos.
Brown precipitant after zinc addition to the AR solution containing gold and SMB hence the sulfur smell from the reaction.


The same brown gold powder being filtered and to be processed using the methods described by Harold to purify.


I checked the liquid left from filtering and tested negative for gold. I really enjoyed this learning experience. I am always thankful to all members here who have helped me through.

Regards,
Kevin

 

[Geo]

thats still very contaminated. your only half way there. now is the time to dissolve it again, but this time you can do it without AR or even nitrates. you should incinerate, but because we are expecting it all to dissolve anyway, it is ok to skip that this time. put the material in a clean container like a scratch free beaker or coffee pot. no heat is needed for this reaction. add 50 or so ml's of hcl to the material. add 10 ml's at a time of house hold bleach and stir.WARNING : chlorine gas will be emitted so do this outside and dont stand over the reaction. look at the material after a couple of minutes,if there is solids add another 10 ml's of bleach and stir. it should only take a few bleach additions to dissolve it all. no need to expel nitric or evaporate. let the solution sit uncovered in a safe place for 24 hours to let the chlorine to gas off. dilute with 2X water and add SMB and stir.

enjoy.

 

[kjavanb123]

Oops,

I went ahead before Geo suggestion, rinsed the brown powder in filter into beaker, followed purifying procedure. Boil in water 3x, decant, boil in muratic 3x decant grayish stuff, now I am left with gray powder, no sign of brown gold power I started with. What the heck just happened??? Thank God I only did this on a 100ml sample.

Thanks
Kevin

 

[Geo]

did you keep the wash solution? the material still contains nitric acid. you cant wash it out, it has to be incinerated. when you added hcl you made a weak AR solution. test your hcl wash and see if you get a positive.

 

[Harold_V]

I would have recommended that you not use zinc, but copper instead. That way you wouldn't have cemented any copper that may have been present.

I would also comment that in Geo's post, he failed to make mention that before your solution was to be precipitated, that filtration is a requirement. Otherwise you recombine unwanted particulate matter with the precipitated gold, defeating the purpose. I make mention because some readers may not be totally familiar with what's being done, and could get the impression that filtration isn't required. I had a standing rule---no value bearing solution was to be precipitated without being filtered first.

What has happened can be best revealed by you doing proper testing. Each of the solutions that are involved must be tested, to verify what they contain. The remaining material (the solids you mentioned) may be silver chloride, although I have no way of knowing if that's the case, or not. Silver chloride is soluble in ammonium hydroxide, so a tiny sample can be tested to see if it dissolves. If it does, it can be recovered by the addition of a little HCl. Testing is everything. No one should refine unless they have a firm understanding of the procedures. Otherwise, you work in the dark and have no idea where your values are, or if you even have them.

A report on your findings would be interesting and constructive.

Harold

 

[kjavanb123]

All,

I still do know what went wrong here, the sample taken from solution is positive for gold, I added zinc powder it foams up, after few additions, I checked the solution and negative for gold, so I filter the brownish mud, add water, boil 3 times, decant, test the decant solution and no sign of gold in it, so I wash and boil 3 times with hcl, no color change, but everything clumps together and the dark brown I started turn into gray mud. I add some peroxide at room temperature and the gray mud comes to the surface and solution is reacting, I filter the gray mud and check the green/yellow liquid and no sign of gold.????

I am going try Geo tip on dissolving the dark brown mud from zinc precipitation in hcl + h202 at room temperature.

Thanks
Kevin

 

[kjavanb123]

All,

I am still confused about what went wrong with process. Here are some more testing on samples.

This time i followed Geo's advice. I removed 40ml of "troubled" AR solution, added zinc, precipitated the powder as you can see in the following


Tried to dissolve the above in AP at room temperature, reaction started but the remaining powder just cling together and just stayed on the surface as u can see in the following picture.


So i filtered it, and tried to dissolve the cling material in AR, and it produced this 2 greenish buttons that just won't dissolve even with heat????


This is the only brown powder left from the "troubled" 1500ml AR solution which i have been trying to purify further.


The powder prior to water washing


Your comments are welcome. I stuck a piece of copper wire in the remaining 1500ml solution to see what is going on.

 

[Geo]

I am going try Geo tip on dissolving the dark brown mud from zinc precipitation in hcl + h202 at room temperature.

actually, it was hcl and bleach. hcl/Cl leach. it dissolves gold foils and gold powder very well.

if you precipitated with zinc, the precipitate will be contaminated with the zinc. straight hcl can remove this.

im sure by now you understand this all happened because you had too much nitric in your reaction. to avoid this in the future, only add nitric and small increments only until the material is dissolved. it saves on chemicals, reduces waste and helps when precipitating.

 

[kjavanb123]

Geo,

Thanks for your help. I stuck a copper rod and iron rod into the "troubled" solution, but purified the remaining brown powder according to instructions here in this forum and it is on process of being dried. I will keep you posted on that situation.

Instead of nitric addition, when re-dissolving the gold powder I used hydrogen peroxide ( AP method ) and it worked out just fine, just few drops of water to rinse it, and added SMB to the solution immediate gold precipitation occurred. So this new batch of 5 Intel Pentium MMXs I just added enough peroxide to hot hcl till no more bubbling and fizzing occurred. So after the beaker reach the room temperature I will decant it to another beaker which holds ice cubes, drop some sulfuric acid and wait for any sulfates or chloride deposits, filter the solution clean, try to add SMB to it hopefully this time I won't have any problems.

I am still confused what to do with my "troubled" AR solution from previous batch, it still shows gold in it, I stuck this rod into it and few hrs later some brownish mud stuck all around it.


It has been a great learning experience for me in gold refining,
Thanks all
Kevin

 

[tek4g63]

Sorry to but in on your topic, but this sounds like a pretty big mess. And unless I have missed something, there has been a lot of missreading of information and a bunch of trying crazy things witout asking first and waiting for direction. You don't have to get in a big rush, as long as you don't throw anything away your gold will still be there waiting on you.

I have a growing collection of ceramic CPU's that I plan to process one day and when I do you can rest assured that if Geo,Palladium, or Harold take the time out of their day to instruct me then I will take all of their advice and wait till questions have been answered before moving on. I'm happy to see that they and many others are giving up their time to help you and I wish you a sucessful recovery of your values.

 

[kjavanb123]

Hi Tek,

Thanks for your support. I have been following instructions, I messed up in removing excessive nitric, so I let the messed up AR solution to sit there for a while till I fix its problem. My experiments with PGMs and catalytic converters have been really great help to find my way in gold recovery from CPUs which is a lot easier it seems.

Here is another picture show of new batch, Intel Pentium MMX, there are 5 of them, you need to warm them up a little and the silver color lid will just come off with a tap.

Intel Pentium MMXs ready to be leached using AP method.



CPUs inside a beaker of warmed up HCL.


Introducing hydrogen peroxide 25% to the above solution and immediate reaction begins.


AP solution after an hour of heating and addition of peroxide in 10ml increments till reaction slows down.


This is stannous test on AP solution after almost an hour and half. I noticed addition of hydrogen peroxide doesn't produce as much as foams as it did and also the tiny little gold foils that used to float on the surface completely dissolved. Another sign that leach is complete.


Regards,
Kevin

 

[tek4g63]

Mmmmmm thoes look good even when being cooked. Lol.

I wish you success on this next batch and I hope that it all goes a lot smoother for you. I will be taking notes along the way, so please don't spare on the details.

 

[kjavanb123]

Tek,

This forum is all about helping each other, and as we all say you get what u give, I owe whatever I have learned in practice to members here Steve, Lou, and many others who take time to share their expertises.

The Intel Pentium MMX batch went pretty well, I dropped the silver/lead but noted that dissolving gold foils on chips is not complete so i ran another AP on them and gonna be added to my already cooled off AP solution. I have used AP ( aqua peroxide ) on palladium and it dissolves it at room temperature, but with gold I noticed you have to refresh your warm hcl before adding any increments of peroxide so the dissolving gold becomes a lot quicker. I kept adding small amounts of peroxide and foams were made, but after they settled still could see the golden foil stuck to the chip, as soon as I added couple drops of hcl to the beaker, and waited for a few mins for it to reach the same temperature then added a drop of peroxide the same fuming and foaming takes place but once settled a large portion of the same gold foil on chip was dissolved. So this might be something to take a note. I remember the ratio of Hcl to H202 in AP was like 10:1, so it won't hurt if you have more muratic to begin with.

I will post more pictures as I finish up this batch.

Regards,
Kevin

 

[Geo]

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.

 

[samuel-a]

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