# Dissolving PCB or Incinerate?



## Captobvious (Nov 7, 2012)

Curious if there's an easy way to simply dissolve a PCB or if Incineration is preferred? Reason I ask is I read somewhere that a Sodium Chloride solution could dissolve them, but unfortunately that's the extent of my knowledge on this particular chemical. Has anyone tried this? Or is it too difficult to scale up?


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## ericrm (Nov 7, 2012)

:shock: sodium chloride? for real?

edit : realy for real?

edit 2 : enuf kidding, i think your mixing to many thing. i migh be wrong but i think that you mean sodium hydroxide can dissolve board, and the answer is no, sodium hydroxide will only disolve some solder mask(not all)

for complete board you have the choice ,your separate by hand or you incinerate....


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## Captobvious (Nov 7, 2012)

Sorry I just looked this up again and turns out my memory wasn't accurate. It was Ferric Chloride I believe..... I think.... I know it was a form of chloride.... yeah not a lot to go on I know.

I should also note that I have NOT attempted this yet, still have plenty of boards left to depopulate before I get to this point, just researching for future use.

What about Acetone or Caustic Soda?

Trying to find something that will simply dissolve the PCB and preferably leave the copper, silver, gold, etc intact if possible. If not a method of extraction would be nice.

Also just to clarify, I've been depopulating boards with a heat gun to melt the solder leaving behind a stripped circuit board. Since most places won't accept them stripped, I'd like to find a way of using the whole buffalo so to speak


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## g_axelsson (Nov 7, 2012)

Ferric chloride only dissolves the copper, just as the AP process with copper chloride does. The board is untouched by the solution.
Ferric chloride is sometimes used to etch circuit boards on a hobby basis, by people that builds electronics at home. I have about a kg left from when I was a kid and built a lot of electronic stuff in my room.

/Göran


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## Captobvious (Nov 8, 2012)

I also read about using sulfuric acid but this seems like it would create a lot of waste solution, also then there's the issue of dropping the copper etc out of solution as well. I saw acetone will likely soften the PCB's but still nothing on just dissolving just the PCB. Only way I've seen to do that would be incineration, that jsut seems a bit difficult to scale up is all.

Thoughts?


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## jimdoc (Nov 8, 2012)

Captobvious said:


> Thoughts?



Process the easy stuff, sell the boards to someone that is set up to deal with the waste.
Concentrate on the higher yielding items. Unless you are totally bored and like wasting time and money.

Jim


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## butcher (Nov 8, 2012)

It is hard enough to get gold from electronic scrap if you just concentrate on the part with high gold yield mechanically separating the parts and metals as much as possible without loosing money.

But trying to process everything not only are you setting yourself up to your loose money but also the gold you may have gotten from working on these parts separated from the rest of the material.

Processing whole circuit boards would create tons of waste using up lots of acids, for virtually no profit.

As Jim say's wasting your time. 
This time could be used to make a profit, and not just making one big mess of waste to deal with, throwing most of your values away with the waste..


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## Captobvious (Nov 8, 2012)

Cool, and thanks for the advice. Do scrapyards or anywhere else take stripped green boards that you guys are aware of? Reason I ask is I've emailed a few board buyers and they don't accept stripped boards, only fully populated ones


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## patnor1011 (Nov 9, 2012)

Find county recycling bank which accept electronic scrap. You can get rid of them in that way. 
I do not see much value in stripped motherboard. It is beyond possibility of hobby refiner to extract any value from them economically.


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## jimdoc (Nov 9, 2012)

If your local scrap yard buys low grade boards just throw them in with them. 

Jim


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## RikkiRicardo (Nov 10, 2012)

What we do is collect till we have 10 Tons then send to copper Refinery I'm sure there are lot of other people doing this.


Rikki


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## Captobvious (Nov 11, 2012)

RikkiRicardo said:


> What we do is collect till we have 10 Tons then send to copper Refinery I'm sure there are lot of other people doing this.
> 
> 
> Rikki



Gotcha, so just hang onto them, box them up and wait til you have enough to make it economical to sell them.


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## hatemelborai (Nov 3, 2014)

dimethyl sulfoxide (DMSO) solve PCBs
the team manually remove the electronic components on waste PCBs and cut the remaining bare boards into fragments of approximately 1–1.5cm2 or 2–3cm2. Then, under a nitrogen atmosphere, the fragments are heated with DMSO. The DMSO swells the brominated epoxy resin, which separates the PCB layers. The solution is then filtered and separated, and the used DMSO is regenerated by evaporation under vacuum to leave the separated polymer resin and the circuit board components.


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## kjavanb123 (Nov 3, 2014)

A Chinese company uses a recycling system on bare boards and recently they have built a machine called automatic electronic components removal which operator load it up with kilos of boards it spins like a cement mixer and heat the solders melt them and roation make the components fall through a mesh so its output will be bare PCBs, tin solders, and all components on boards.

The bare boards go to their PCB recycling system which basically shred, pulverize and use either a shaker table or dry one to separate fiberglass epoxy from laminted copper sheets used in the bare PCBs.

They use ozone (o3) fired furnace to burn the plastics from the dismatnled components and use dilute sulfuric acid to dissolve base metals, and dissolve the remaining undissolved metals copper, silver, gold and palladium in AR, finally use electrowinnig cell to plate copper, gold, silver and palladium.

Their products from this system is tin ingot, copper powder, gold, silver, palladium and fiberglass which is sold to insulation making companies.

They have fume hoods and waste treatment system, I recieved a quota from them for 150kg per hour full recovery system for $160k. Their automatic dismantling machine seems simple yet effective as you can see in multiple youtube vidoes. It also comes with a fume scruber as it produces some smoke. It costs is around $14k with complete scrubber.

I have tried another method myself, had about a pound of shredded PCBs and removed magnetite components, then leach them using 10% sulfuric acid, after two hours all tin solders or aluminium and solder masks were dissolved, and it looks like copper and gold plating are left. Picture below,



Another option would be to use labour or manual dismantling components, process separately.

Regards,
Kevin


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## FrugalRefiner (Nov 3, 2014)

kjavanb123 said:


> They use ozone (o3) fired furnace to burn the plastics from the dismatnled components and use dilute sulfuric acid to dissolve base metals, and dissolve the remaining undissolved metals copper, silver, gold and palladium in AR, finally use electrowinnig cell to plate copper, gold, silver and palladium.


Silver does not dissolve in AR.

Dave


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## kjavanb123 (Nov 3, 2014)

My apologies, silver will be collected as chloride that will be converted to silver using zinc cementation, I put it next to other metals that get dissolved in AR.

Then AR solution go through series of emew electrowinning cells to plate copper and rest of precious metals. Chinese have been around the largest ewaste in the world, so to me they know ewaste recycling better.

Regards
Kevin


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