A passive stripping system

[Shecker]

Dan I just go over the boards with a hammer, breaking up what I can. No one is going to get everything. Since I am one old lazy --- dud, I do whatever requires the least work for the best return.

Randy in Gunnison

 

[cerise]

Wouldn't one want to burn the e scrap first? Then Hot HCL. Or AP bath.Just wondering.

 

[Shecker]

Cerise that is better answered by someone else on the forum. I don't burn off anything until I am ready to smelt the sludge that builds up on the bottom of my tank. I smelt with borax, sodium carbonate, silica, and a little flour as a reducing agent. The palladium (and any platinum that may be present) will end as a matte phase so watch the slag when breaking it up.

Randy in Gunnison

 

[goldsilverpro]

If you burn E-scrap, it produces very toxic, very black smoke (lots of it). You'll never get away with burning even moderate amounts without spending tons of money on pollution control equipment, such as scrubbers and baghouses.

In this day and age, burning is not an option, unless you do it legally.

 

[pcecycle]

I am trying a small scale experiment using this system. It seems to be going well. Some items are completely stripped and some are only partially done after 5 days. There is a good bit of sludge forming that I assume contains all the values.

After filtering off the sludge, do I just dump it into nitric to recover any silver or palladium, then filter the residue and treat with AR or HCL-CL to recover any gold?

As long as the solution remains blue-green and clear, I assume I can still use it to strip more items?

Also, does aeration help as it does with AP?

Thanks

Mike

 

[Shecker]

That sounds good Mike. Just post your results for others.

Randy in Gunnison

 

[Scott2357]

Any pictures or updates on this?

 

[Ignatz61]

Is there another way to recover the silver without using nitric--for those of us that can't get it easily?

 

[Shecker]

The silver should readily dissolve in sulfuric acid as an alternative to nitric acid. recovery can also also be by cementation on copper and then re-refined if so desired to obtain high purity silver. I do have some pics but I have been unable to post them on the forum.

Randy in Gunnison

 

[NaNO3]

Concentrated sulfuric acid H2SO4 may be used in combination with heating for silver-gold alloys with more than 10% silver content.
The process is termed affination.
A maximum gold content of 30% is recommended.
The sulfuric acid produces copper sulfate CuSO4 and
silver sulfate Ag2SO4 from those metals in the alloy.
The Ag2SO4 is precipitated by the addition of cold sulfuric acid H2SO4. Two to three washings with acid removes the copper sulfate CuSO4 and the procedure can leave almost pure gold (Ganzenmüller p 345).

 

[Scott2357]

Posting some pics for Shecker... Comments are his.

 

[lazersteve]

Scott,

Your lack of proper safety gear really astonishes me. :shock:

I'm not convinced that you are seeing silver sulfate, especially with all the other metals higher up in the activity series in the mix competing for the chance to react with the sulfate ion.

You'll need better proof of your claims than the above photos to prove you are really getting what you think you are. How about some photos of pregnant solutions and positive stannous test swabs.

How many boards did you process for the yields quoted?

Steve

 

[Scott2357]

It's perfectly safe for me since I'm not within a thousand miles of it. Please re-read the "Posting some pics for Shecker... Comments are his." part at the top. I don't know anything about this, just helping get the images posted.

 

[Shecker]

If you recall Steve you are the one who correctly called it as silver sulfate in a pm to me quite a while ago.

Randy in Gunnison

 

[Harold_V]

Call it what you wish-------I, for one, don't believe it (the silver claim, that is).

Has any of it been melted, then tested with Schwerters?
Or------has any of this supposed 'silver' been melted and refined through a cell?

I'm having more than a hard time believing that silver is used in abundance on boards. Didn't GSP mention (previously) that silver is not desirable for such use?

Any comments to support the claim will be appreciated. Opinions not so much.

Harold

 

[Shecker]

I also run a lot of tv boards and there is silver in those. I also run silver plated wiring. What I have reported is what I recovered. I am not here to convince those who will not see.

Randy in Gunnison

 

[jimdoc]

Since you are doing the whole boards maybe you have tantalum
capacitors in the mix? Some are supposed to have silver cases.
Jim

 

[goldsilverpro]

Silver sulfate is white, not yellow.

 

[lazersteve]

Scott,

Sorry I missed the fact that you were a go between.


Steve

 

[lazersteve]

If you recall Steve you are the one who correctly called it as silver sulfate in a pm to me quite a while ago.

Randy in Gunnison

Randy,

I don't recall the exact PM you are speaking of, but I most likely said that some solders are made of an alloy of silver and that sulfuric acid and silver can form silver sulfate under the right conditions. That's not to say that all solders are silver alloys. As for reactions that form silver sulfate, I would need to know more about the chemistry of the mix to determine if silver sulfate will even form under the given conditions.

The part that makes me skeptical is that all the other base metals present should be reacting to some extent with the sulfate as well. This makes for a very dirty reaction which is difficult to determine exactly what the products actually are.

Steve