# Process with a difference



## NoIdea (Sep 18, 2016)

Dear All, my absence has not been in vain as I am trying a new process that uses way less chemicals and has been very effective in dissolving all base metals quickly leaving behind the gold and other PM's, interested?

Drafting this process can get rather confusing and still has a few question that need answering, so your help will be invaluable. It might take me awhile to get it all on paper as I have this amazing ability to digress with ease, which may add to the confusion.  

Process Material:
Anything containing visible PM's and silver, for example, gold and silver coated pins/plugs, IC's and flat packs, TO type packages, laser diodes, LED's, solder silver/lead, tantalum capacitors, any small surface mounted components, silver ribbon, keyboard Mylar's, x-ray and photos, etc.

Pyrolysis:
Nothing new hear except when doing Mylar's, x-rays, and photo's they need to be placed on the bottom of the reactor as the silver/silver oxide becomes mobile in the pyrolysis gases phase. Years ago I pyrolyzed a bunch of Mylar's and photos, to my surprise the silver precipitated or phase changed into a solid mass close to the gas exit point. I'm not sure how much silver was lost butt it made me weary when it comes to their placement within the reactor, at the bottom the silver has a better chance of precipitating within the system rather than being lost with the pyrolysis gases.

Grinding/Washing:
Objective here is to grind the charcoal/fibre glass, left after pyrolysis, to a size that will allow washing to remove most of it through density floatation leaving the denser metals behind. The charcoal residue is kept and will be dealt with at a later time.

DO NOT ASH THE PYROLYZED MATERIAL.
DO NOT REMOVE MAGNETIC MATERIAL

The Reactor:
This next part has eluded me for years, yet has been a visual part of my studies, butt just couldn't see it. The reactivity series gave me a clue as to what might be happening, though allot of what I'm about to present has allot of assumptions an speculations that need confirming.

For years I have been trying to dissolve the base metals, excluding iron, with sulphuric acid, talk about slow. Then it clicked, a self sustaining electrochemical cell without external electricity. We are all aware of the iron/copper battery that can be made using a lemon/orange as the cell, well what do you think will happen if you wrapped a piece of copper wire around a nail and then drop this into dilute sulphuric acid? Yep the cell is shorted out and both the copper and iron dissolve, however any copper that is dissolved will reduce back to copper when it come into contact with the iron and will keep doing this until the iron is gone. Now, lets say we put the washed pyrolyzed material into a shallow tray and add dilute sulphuric acid, just enough to half cover it, now just walk away and let it do its thing. Any metals that are electrochemically different with react with each other. The reactivity series shows that copper is the least reactive base metal and as such any copper sulphate produced will soon be reduced back to copper as a very very fine power due to the more reactive metals present. However when the free acid is consumed, we are left with a iron/nickel sulphate electrolyte which still enables the cell to continue, butt instead of producing copper sulphate, copper(I) oxide is thrown down as a fine light brown/orange precipitate along with finely divided iron oxide (orange rusted) which can be removed by adding water or old iron/nickel sulphate solution and shacking/swirling the tray(like you would when panning), the light brown looking mud just stays in suspension and is easily poured off into a bucked (keep this aside and ill show you later how to recover the copper) making sure none of the denser material is allowed to follow, this is why a bucket is used so if by chance some of the heavier material does end up in the bucket it will sit on the bottom. Now if you keep the reactor material damp with the iron/nickel sulphate solution the reactor will keep dissolving the base metals and more material can be added. Now this is where it starts to get interesting, instead of using the iron/nickel sulphate to wash the reactor tray, we use dilute sulphuric acid then a white precipitate is formed containing lead and silver sulphate and is way less dense than the brown precipitate and can easily be separated through sedimentation. So it would seem that using the iron/nickel sulphate wash suppresses the formation of lead and silver sulphate.

Gunna take a break now as my head is going fuzzy :? 

Regards

Deano


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## rewalston (Sep 18, 2016)

Sounds interesting, I'll be following this.

Rusty


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## Geo (Sep 19, 2016)

The reaction could be sped up by applying heat. A heating pad under the bucket or tray. You would have to put a layer of thick plastic between the pad and container to protect the pad. Speed is the limiting factor. If you are working with your own material and time is not a factor, you could use this on hard to deal with material. It seems like a twist on AP.


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## kurtak (Sep 19, 2016)

:shock: That the holy crap look --- not the shocked look (being as how it comes from you Deano - because nothing you come up shocks me mate) :mrgreen: 

Going to have to re-read that a couple times to fully digest it :lol: 

Can't wait to see the rest you have to say on this one 8) 

WELCOME back Deano :!: --- for someone that goes by Noidea - you sure have a lot of them :mrgreen: 

Kurt


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## NoIdea (Sep 19, 2016)

Well, back into it. I tend to get carried away and forget a few steps not mentioned, my mind works way way faster than my typing. I know by the time I have finish my novel, the information will be fragmented to bits, sorry for this, It's the way my mind works. :roll: 

There are a number of other factors that influence the dissolution of the base metals that need to be mentioned, that is, the air oxidation of the metals and the air oxidation of ferrous to ferric and copper(I) to copper(II) which is used for copper etching, and of course the need for iron to reduce copper. 

There is also a need to keep an eye on how well the gold is being undercut and fallen off, their is no need to dissolve more base metals than required, the pyrolysis and grinding of the material, before entering the reaction tray, has the effect of compromising the gold plated surface allowing for easier undercutting of the gold. If the gold plated surface is not compromised, then the plated material will just sit in the reaction tray unaffected for a very long time. If the reaction tray becomes stagnant, then the chances are more iron needs to be added, the resulting iron oxide can be removed through magnetic separation.

Yes Geo, heat would speed things up, that's why I put the reaction tray outside in the sun, by the end of the day the tray contents have set solid which needs breaking up and more iron/nickel sulphate solution added. 

After a fashion, a week or two, the reaction tray will need to be ground again and sieved through a -40 mesh. Depending how well the material, above 40 mesh, has been under cut to release any PM's, will determine the next course of action, either put it back into the reaction tray with additional material or it's put into a home made rock polisher which will brighten or polish any copper or brass not dissolved, and should remove any external PM's but not the gold filled items.

The released gold will migrate towards the bottom, every time the tray is mixed and shaken, and will stay there in a dense mud.

The material that passes through the mesh contains the PM's, unreacted metals, metal oxides, including more lead oxide, copper(II) oxide, iron oxides, copper, iron, and lead plus others yet to be determined.

At this point I'm in two minds as to what to do now, I could either put the -40 mesh material into a separate reaction tray for continued dissolution of the base metals still present, or I could pan out the gold, or even ash the material and proceed that way. Of course this would be after the removal of any iron oxide by magnetic separation.

Well time for another fuzzy head break, all comments welcome.

Regards

Deano


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## NoIdea (Sep 21, 2016)

Evening All - Firstly I would like to apologize, again, for what is going to be a some what fragmented process, that's how my mind works, in fact, if I could, I would first analyse my brain then have it defragmented, because as it sits now, my brain is here there and everywhere. When and if I ever finish this written copy of the process, I was wondering if anyone out there could possible pretty please put it together in some sort of logical order. 

Please don't ask me to explain what's going on inside the reactor, because I really, I have NoIdea, well I might have a wee clue, what you are getting are years of observations and digesting, nothing more, nothing less, and you your selves may have observed the same as I have through your time digesting what you digest. The thing is, knowing what is soluble and what gives white, brown, black precipitates of sulphates and oxides, can't forget the reactivity series, when the penny dropped it was like all that information started to form a jigsaw, and my observation, which at the time were mental notes, started to make sense.

Ok, now where didn't I get up to. :? 

Grinding and washing(again).

After washing I sieve the material though a 40mesh sieve, the material that is greater than 40mesh goes into the reactor, anything less than 40mesh is ashed and put through my miniature sluice thingy, pictures below shows it all, it's a piece of 50mm by 50mm by 1.5m conduit without the lid, the mat is wool carpet, on top of that is tough plastic garden boarder stuff, comes in 10metre rolles and about 200mm wide, this is held in place by plastic rectangular blocks screwed into the PVC conduit.




Here is a picture of the reaction tray (Perspec's record player lid), of which the contents has just been cleaned, ground, sieved, with the >40mesh material being put back for more digesting.




Having the base metals work for you without any supervision, and only spending a short time mixing shaking the reaction tray, along with me being able use buckets to do my chemistry is a bonus. :mrgreen: I use sulphuric acid because of it's lack of volatility, releases virtually no acid vapour (dilute acid), I have used HCl before butt my tools kept rusting :roll: 

Um, shall we go revisit the Process Material:

Above I gave a description of what goes into the pyrolysis reactor, here I will let you know what I keep out. 

All electrolytic capacitor(keep these aside, they will be used later), poly type capacitors, non-PM coated plugs and connectors, inductors, iron packaged crystals (without visible or known PM's), metal framing except for the soldered bits which I cut off for the reactor(Don't Pyrolyze), high wattage resisters(ceramic type with wound nichrome wire), transformers and wire. 

I firstly remove what's not wanted then I chisel off the rest, even going as far as making sure both side of the board are smooth to the touch, this material is sieved trough a 5mm copper colander bowl 200mm diameter by 50mm depth, kind of cute really :lol: The small stuff that falls through the 5mm sieve is put into the reactor tray, after grinding and without pyrolysis, otherwise the solder will melt into big blobs which take longer to digest. 

The lead and silver react very quickly to give the corresponding sulphates, and if you don't remove these sulphates quickly they disappear, more than likely converted back to their corresponding oxides, bit of a waste to have to reconvert them back to the sulphates. The lead and silver sulphates I once had, were placed in a 2lt ice cream container, kind of jelly like consistency, to which I put an unknown quantity, butt fairly saturated, solution of NaOH , and left it in the sun, mixing it each time I walked past and adding more NaOH solution to prevent drying out, no colour change for the first three days, and on the fourth it had turned black, all black, threw this into a forty gallon drum with heaps of stuff to pyrolyze. Umm it's been pyrolyzed, has been for awhile, about a year now, still sitting next to the bonfire pit, guess that's another story. :mrgreen: 


I decided to pan the <40mesh material because I saw the pretty stuff just begging to be release. Currently, the panned stuff is being digested in hot battery acid, will keep you posted.

Regards

Deano


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## NoIdea (Sep 23, 2016)

After Noon All - well I decided after reading a thread on processing switch contacts that I would stop rabbiting on and show the process in action.

With a small amount of contacts and some gold coated pins, the pins were put through a grinder to scratch them up a bit, and a steel/iron lid from some electronic scrap. Putting the lid onto a plate followed by the pin and contacts.




Next I covered the lot with an old solution of iron/nickel sulphate.




After two hours.




With a quick wash and the addition of some more iron/nickel sulphate solution.




After four hours.




Well that's that for now, Saturday tomorrow, ill take some more pictures when I wake up.

Cheers

Deano


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## g_axelsson (Sep 24, 2016)

That looks like a perfect example of contact corrosion.

Göran


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## jason_recliner (Sep 24, 2016)

g_axelsson said:


> That looks like a perfect example of contact corrosion.


I see what did you there.


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