A passive stripping system

[Shecker]

Good afternoon everyone

In my work I use a lot of CuSO4 for leaching complex minerals. Awhile back I discovered that CuSO4 will also strip the silver from CD's and DVD's and the silver will simply fall off as a gray powder. Today I tried this with electronic scrap from several different computers. I found that CuSO4 plus occasional additions of 3% H202 slowly strips the precious metals from the e scrap. And it does this without dissolving the copper or other base metals. The silver and pgms fall out as a gray powder and the gold falls out as a micro fine yellow powder. The system is slow but works easily on a 5 gallon bucket basis and leaves a residue for further refining that is not contaminated by base metals. I believe this is worth trying.

Randy in Gunnison

 

[Rag and Bone]

Are you sure there is silver on cd and dvds?

 

[Scott2357]

Some form of aluminum I think.

 

[Shecker]

According to guys like Jim Sinclair, there is a thin film of silver on CD's and DVD's that is considered unrecoverable by usual means. The value is about 5 cents per disc and is considered a loss of metal to the environment (like a lot of other nonrecoverable silver uses).

My trial on e-scrap is working just fine and I can visually watch the gold being slowly removed from the connectors. Copper and solder materials are left behind.

Randy in Gunnison

 

[P_CARROLL]

Which form of copper sulafate do you use the hydrated blue stuff nor non hydrated whit powder

 

[SilverNitrate]

never the less, if you used H2O2 on your fingers that can loosen the foils sufficiently enough to rinse away. I believe that CuSO4 in water will do nothing to react with anything besides base materials like iron, zinc, aluminum, and perhaps the tin, and lead solder.

I say you'll have better luck with NaOH and little H2O2.

 

[Shecker]

I use hydrate blue copper sulfate. When I use it on e-scrap with H2O2 that precious metals comes off in the form of fine powders. Gold is a bright yellow powder and silver/pgm's are gray powder. I have found that in 4 to 5 days the copper sulfate works its way into the chips and processors and slowly strips them. Some gold goes into solution. Certainly some of the copper sulfate will react with the stainless steel and other non-copper base metals present and reduce copper upon their surfaces. I have found this does not interfere with the process. If necessary I add some extra CuS04 and H2O2 to continue the stripping process.

I don't normal run e-scrap and I started as a n experiment. But it has worked very well for me.

Randy in Gunnison

 

[NobleMetalsRecovery]

just wondering if anyone has tried this with pins?

 

[Palladium]

8) ?

 

[SilverNitrate]

CuCl2 is water soluble and won't precipitate. Most copper compounds including precipitates can be dissolved or removed with ammonium NH4OH-

 

[Paige]

For us idiots, what is ammonium NH4OH?

 

[Gotrek]

For us idiots, what is ammonium NH4OH?

NH4OH = Ammonium Hydroxide = Ammonia(aqueous(in water))

 

[donald236]

i really hate to be such a big dummy but what is cuSO4 &clcu2 :?:

 

[steveonmars]

When I don't know one of these terms I just Google it and have the answer in a few clicks. When you google something you almost always end up with more info than you were looking for if you want to keep looking. It's amazingwhat you can learn just by looking up a simple term or formula.

Steve

 

[Platdigger]

Copper sulfate and copper chloride, which is actually written CuCl2
not the other way around

 

[Anonymous]

Hae guys
Im trying to strip metals (gold silver and copper)
from scrap useing copper sulfate I have a contaner that has water and cuso4 mixed in I then added a whole lot of circuits and a cd that i broke ( also added a few gold fingers and flat pack.) the cd is almost stripped but its taken AGES and the boards (still with plastic covering) is progressing really slowly. anybody Know what i should do?

Also there is a small amount of floaty particals building up at the bottem of the contaner how do i collect these and check if there are any metals that makes it worth while continueing with the CUSO4 prosses

any help will be greatfully and thankfully welcomed

thanks a heap!!!!!!!

DAN.E

 

[Anonymous]

Not sure that just adding boards for copper sulfate will strip them. I think the only thing that would happen is stuff like aluminum, iron etc that is more reactive than copper will displace it from the solution, is that what you are trying to do?

 

[Shecker]

Add some hydrogen peroxide. First it will increase the effectiveness of the copper sulfate and second it will precipitate silver as a bright yellow material that is easily filtered and then processed into nitric acid for the reduction to metal. But you also need to break the surfaces off of any IC's and the main processor. It takes about a week for all of the stripping of exposed areas to be be completed. That is why I call it a passive process. The good news is that if leaves the solder alone so no tin or lead fills the solution. I also make sure that as much as possible all aluminum and iron are removed from the boards as this will cause copper/gold/palladium precipitation. I always end up with a copper based sludge in the bottom that contains everything but the silver, but that sludge is easily processed into separate metals. This works well for me because I don't have to stand over it while it is running. There will also pm's in the solution so I would check it first. A little note -- stannus chloride has an unusual reaction with copper and can mask any other metals present so I check the gold with SMB. The palladium from the monolithic caps always ends up in the sludge residue. I hope this helps.

Randy in Gunnison

 

[Pawnbroker Bob]

Hi Randy,

Your process interests me. Could you please post a little more detailed explination with quantities? ie How much CuSO4 with wate and H2O2 used.

Also you mentioned some values go in to soultion. How are you preciptatng them out?

I was reading an article the other day indicating that some high end dvd's do contain gold values.

Thanks,

Pawnbroker Bob

 

[Shecker]

I have a 71/2 gallon tank I fill with boards, cards, and memory chips. I fill it with water and add one pound of copper sulfate. A few others later I add a little hydrogen peroxide. Every now and then I add a little extra copper sulfate and hydrogen peroxide. I do this for about 5-7 days, then filter the solution. There will be a copper sludge in the bottom that weill contain some of the pm's and some will be in solution. I remove all other values with iron which drops them into a copper base. This is adaptable to virtually any scale -- but remember the copper sulfate won't work on values thast are not exposed. So take your frustrations in life out on the boards and leach away.
From there the values can refined by standard means. Essentially this is a metallic replacement process but it does remove the exposed pm's.

Randy in Gunnison