help needed

[undero2]

Hi,

I am having trouble with my recovery process and am in search of assistants.
currently I have tried to remove gold from ceramic cpu's and feel I had done correct steps but am empty handed. I had broken pieces of cpu's and placed in beaker covered in HCL (32%). placed on heat in and slightly diluted with water. let sit in this position for 2 hrs. then put around 1tbs of sodium nitrate. let the reaction take place and watched it off and on until process was complete. let cool by itself. Next, placed some ice in a separate beaker and decanted leaving remains of cpu's. (cpu's show no gold plating) So I feel like the dissolving is a success. I used 10 drops of sulfuric acid, to drop silver and pb while still cool. but I test with sncl and my solution does not stain? the gold is gone but not in solution?

I continued to check broken cpu's and all gold was gone. washed with water several times and decanted.
In the other beaker I have dark greening solution and now use SMB to precipitate gold. I left it alone over 24 hrs and some precipitant is there but, it still remains dark green and the precip looks like white stump out (SMB) @ the bottom. So should I decant? The sncl test is still neg. Is there somewhere I went wrong and is there something I can do to still recover it? I believe its there b/c it didn't vanish.

any questions or comments will thankful

 

[lazersteve]

... decanted leaving remains of cpu's. (cpu's show no gold plating) So I feel like the dissolving is a success. I used 10 drops of sulfuric acid, to drop silver and pb while still cool. but I test with sncl and my solution does not stain? the gold is gone but not in solution?...

Do you see any signs of remaining metal of any sort (legs, lids, etc)?

All metals must be dissolved before the reaction is done. The appearance of visible gold is not a valid indicator of the reaction being complete.

Steve

 

[samuel-a]

Do you have a picture of what you started with? How much?
Or could you describe exactly what you started with?

 

[undero2]

Yes i can take pics Sam. It will be later though. And laser, no didn't see any legs but Your reference to lids what is this?

 

[butcher]

Steve is talking about the large metal heat sinks, of metal lids.

If there was any remaining base metals that did not get dissolved the gold will plate back out onto these metals, these base metals can pull dissolved gold back out of solution, for this reason until all of the base metal is dissolved in this process you may not have all of your gold into solution, the black gold powder if plated back onto base metal may be hard to see, or identify as it will no longer look like gold, if the base metal are hidden like inside pieces of CPU's or in between layers of fiberglass where copper traces can be hidden for example in circuit boards, then your gold could hide their also plated to undissolved metals.

Oxidation is the removal of an electron from the atom (when we dissolve gold we oxidize the gold) the atom then becomes an ion in solution.

Reduction is a gain of an electron, when a gold ion gains back the electron the gold is reduced back to a full atom of gold metal, (usually as a precipitated gold metal powder, or as gold plated onto another metal like copper usually as a black power, or as the fine gold colloidal metal powders like in the stannous chloride test the violet color of light reflected from gold metal floating in solution giving us that purple color.

The stannous test will not work even if there is gold in solution if the tin solution cannot reduce the gold back to a metal (the colloidal, gold metal that colors the solution violet in a positive test is reduced gold). We have to be able to give those gold metal ion back electrons, in the test the stannous chloride is what is trying to supply those electrons.

But if nitric is involved it keeps taking those electrons from your gold.

If you still have free nitric acid (or in this case possibly nitrates salts, reforming free nitric acid with the acid solution), the nitric acid will keep trying to oxidize the gold putting it back into solution, at the same time as the stannous chloride is trying to reduce gold in the solution back to metal, and the nitric can win this battle.

You need to remove the free nitric acid from the chloride solution for the stannous chloride to be able to reduce the gold, and the nitric needs removed before you reduce your gold to metal with a chemical like SMB.

So in a way, your stannous not only can test for gold in solution , but it can also help to act as an indicator to tell you if you have removed enough free nitric from solution to be able to reduce the gold back to metal atoms with all of its electrons,(or be able to precipitate the gold from solution).

 

[undero2]

First, I am greatly appreciative to all of your help. thank you. It really helps to speak to someone besides myself. And you guys are now mentors to my studies. your websites, pics, videos and literature have helped me greatly. Most people I try to speak with think I'm crazy, cooking meth or trip out on me.

nevertheless, all your comments meant a lot. The lids were removed prior to breaking the cpu's. but there are other base metals that did not dissolve completely. So I will try and dissolve in another batch maybe so I can find it? And with the solution if I neutralize it with urea would that make my test positive? I am questioning myself a lot. anyway I can use smaller batches to test this.

I have posted some pics but do not have any prior to the batch.

 

[patnor1011]

Your gold is all still there on undissolved pieces of metal.
Process is still not finished, when done properly only ceramic base of cpu will remain.
You need to process those cpu again till all metal will go to solution.

 

[samuel-a]

Yup... need to run again.
Also, judging by the type and amount of cpu's keep in mind that the precipitation will not look like on the videos.
It will take time to settle completely and all you will see is a thin layer on the bottom. That's the gold.

Remember to test with SnCl2!

 

[butcher]

Urea should be avoided, the ammonium compounds can complicate your solution, it can also create dangerous solutions, and waste, and it just adds another contaminate to the solution, there are better ways to deal with nitric.

To get rid of the free nitric you can use the method taught in Hokes book, evaporating the solution to a thick syrup, and a little HCl to re-wet, this is repeated three times, to insure you drive off all of the nitric acid (it is a good idea to review the procedure in Hokes book, as I did not explain it in as much detail).

There is also Harold's trick of adding a gold button, and a little heat to consume the nitric acid.

Another method similar is to limit the amount of acid and leave a little undissolved gold towards the end, then heat, at this point you can save the undissolved gold for the next batch, or concentrate the solution with heat (using up free nitric and dissolving more gold into solution and add drops of nitric (or tiny amounts of nitrate salt in this case) to dissolve the last bit of gold, being careful not to use more nitric than necessary to finish dissolving your gold.

And you can use sulfamic acid to rid the nitric from solution, (Lowe's has sulfamic acid as grout cleaner in the flooring section of their store),

As always limiting the amount of nitric acid added is always a good idea, to only use what you need to dissolve the gold, adding HCl to the metal and adding nitric in small proportions as needed, when you use nitrates salts and acid to generate nitric acid in solution this is a little harder more difficult but still can be done.

Just something to think about here, (not that you have this situation), if nitrates are added in an excess amount compared to the acid, you can have a situation where most of the acid is consumed from the reaction with the nitrates salts to make nitric in solution, and with the reaction with the metal, these extra nitrates could be in the form of a dissolved salt, or even saturated salts in the bottom of this solution, along with free nitric acid and metal chlorides, heating to evaporation will drive off water and then the free nitric acid but will only concentrate these excess of nitrate salts, adding acid will convert these nitrate salts back into nitric acid again in solution again making eliminating the nitric from solution much more of a challenge...

Stannous chloride needs the nitric removed before the test works properly, the tin chloride solution cannot reduce the gold to give the violet color if your nitric acid keeps re-oxidizing the gold back into solution.

Lets say I wish to test a solution for gold, that has free nitric acid in solution, but I do not wish to eliminate the free nitric from the solution at this point, I can put several drops of the solution to be tested in a spot plate (or in a white plastic spoon), I can add a few grains of sulfamic acid powder, the add drops of my stannous chloride to see the reaction, as a test, I can repeat this test without the use of the sulfamic acid in another well of the spot plate, if the first test showed positive violet color from the reduced gold power in solution, and the second test of the same solution did not react to the stannous chloride (no change in color of solution) then this shows there is still free nitric in solution.

Keep up your reading of Hokes book and doing the getting acquainted experiments in the book, and keep studying the forum, there is a vast amount of things you will discover to help make your work easier, there is a gold mine of information and things to discover.

 

[undero2]

awesome,

I am very excited to experiment these questions and find results. It only stinks that I have to wait until I have more time (off work.) thank you again. And yes I will continue my lessons. I wish I could give you something. Most of the time I don't meet people willing to help others. I hope one day I can continue for you.

 

[au-artifax]

I am no expert by any means, but I did have this experience refining chips and fingers, illustrating just what's being said:
During the process I saw only the color of copper remaining, so I cast off the solids and sought to go after the solution, which I wad convinced now carried all the gold. Come to find out it was not in the solution. The way I found this out was on my next batch. I saw the same thing....copper color on everything. This time I threw it in some Hcl and heated it just to get a better look at the pieces. After while picking up and rubbing the pieces, I found that the copper rubbed off and there underneath the copper Sat my gold. Has anyone else had the copper plate on to of the gold like this?

Anyways, yeah, the moral of the story is to get rid of ALL the metals before you will see ALL the gold. In fact I made that mistake again just recently, but in a roundabout ways (by not inquarting, I had other PGMs that came down with the gold.... Not what I wanted. I should have gotten rid of the PGMs before he gold process, and left over metals and their salts are hiding my gold, and without the knowledge I received listening to Solar, Butcher, Palladium, and Steve, I surely would be inclined to toss it in a bucket till doomsday.

 

[au-artifax]

On another note, don't waste too much time on the white solid. If you want a demonstration why, then take the white solids by themselves and add HCl. Most likely it will dissolve almost immediately into a bright thick yellow solution. The little bit left over would be silver chloride or lead that fell out of a saturated solution.

Anyways, you want this material GONE!!! DON'T TRY TO REDISSOLVE IT IN THE SOLUTION. Most of it is nickel and tin and it will ruin any hopes of filtering any further solutions. It almost immediately starts to crystallize in your filters and when you remove each filter you will notice it is hard as a cracker. Recant or siphon off the top of it, add a little water to rinse, let it settle, then again take the liquids. Use a separate vessel, heat to put these unwanted metal salts back into a solution, then you can return what's left behind back to the main batch because there is still some gold that was not dissolved there.
There may be some silver chloride and elemental silver. This will not interfere with the gold recovery though, unless you want to concentrate on the silver and ignore the gold. Nah....I didn't think so.

 

[undero2]

ran a second time tonight, couldn't wait any longer. And its there! the sncl2 test was positive along with the color, "was dingy yellow, but non the less yellow." I am in the process of precipitating it and have very high hopes in the morning. could not of done it without you guys. sky's the limit. thanks. STOAKED!!!!!

 

[Palladium]

It's like having your first kid !

 

[undero2]

good day,

Not to brag just wanting to post some finishing pics of the batch spoke about. Thx GRF. hooked!!!! Now on to other projects though. I have a tending fascination with the silver cell. And will help anyone if I can.

 

[martyn111]

I had broken pieces of cpu's and placed in beaker covered in HCL (32%). placed on heat in and slightly diluted with water. let sit in this position for 2 hrs. then put around 1tbs of sodium nitrate.

the idea of the HCl bath is to dissolve the base metals from your starting material to remove them before you attempt to dissolve your gold. This would be the recovery stage.
If you had decanted the HCl away from any remaining solids and made your poormacns AR with fresh acid and sodium nitrate you would have eliminated all the metals dissolved by the HCl resulting in a cleaner solution to work with. This would be the refining stage.
By adding the sodium nitrate to the HCl from your recovery stage you have effectively missed out the recovery stage, this is unfortunately a common mistake made by newcomers to refining.