# Grinding down circuit boards?



## jhize

Hi all,

Always on the hunt for more info !

I recently saw a video on youtube that explained what ewaste recyclers do with the circuit boards (chips, connectors and all).....they grind them up...like sausage (really crunchy sausage). Anyway, the guy on the video said that after they are ground up, THAT is when they extract the precious metals. My question:

How do they extract gold from that mess?


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## Lino1406

Are numerous. For example: 1st - incinerate
2nd - A/P


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## scwiers

Be prepared for an overpowering and acrid stench when incinerating; personally, I'm experimenting with crushing down to smithereens in a ball mill, screening, then treating direct w/ HCl to remove base metals, and from there, AR. Basically, mining.

Someone at this site [?] told me that the big operators just smelt the boards directly in a cupola, ensuring 'complete' combustion and little if any bad-smelling stuff. The probelm with that, though, is that several PMs are inside the ceramic chips; I don't think smelting alone is going to do the trick. 

The end result from the blast furnace, though, would be a pool of base metals (mainly Pb, Sn) w/ trace PMs.


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## He's Dead Jim

what kind of temps would be needed to obliterate everything but the metal??


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## NuggetHuntingFool

Actually. Ammen's book has a great method right within the first ten pages or so.

I'm not sure if it pales in comparison to today's methods, but he says it's great for a mix of stuff...


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## Rag and Bone

jhize,

I'm also wondering how somone could deal with extracting the metal from an entire circuit board, on the neighborhood level. Cherry picking the high-yield pieces is alright. 

What happens if you pulverize the board to very, very fine powder. Then, float the powder in water. 

Would all the metal settle and the non-mettalics float :?: 

(remove the bulk of the junk steel, plastic, low value metal and components mechanicaly beforehand of course)


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## enragedcow

I honestly don't think there's an economical/safe method, for a "garage" worker, to remove PMs from whole circuit boards. 

1 - Incineration is out of the question, as it releases a whole host of very nasty fumes. So unless you have an industrial incinerator/scrubber, it's not a safe option.

2 - Milling the parts to smitherines is highly risk too. There can be Beryllium compounds which are extremely hazardous to breathe. Furthermore, the crushed chips create silicon dust, which causes silicosis when inhaled. So, unless you have an extremely efficient way to handle airborne particles, this won't work well.

3 - Acid treatment will be woefully uneconomical for a home user. Between materials cost, and the volume of acid you'll generate (there's quite a bit more base metals per gram of precious metals in a whole circuit board, as compared to clean fingers). 

If you're doing it for fun, stick to fingers and such, and ship your boards off to a real processor/refiner. There's just no way, in my scope of understanding, that a home user can/should try to process them on any sort of a routine basis.


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## goldsilverpro

There are some companies that chop up the materials and then use a series of separation methods - density, eddy current, magnetic, etc. I really don't know any specifics or how successful they are. I think I saw some patents.


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## enragedcow

goldsilverpro said:


> There are some companies that chop up the materials and then use a series of separation methods - density, eddy current, magnetic, etc. I really don't know any specifics or how successful they are. I think I saw some patents.



From what I've seen thus far, those methods are used to break down whole electronics. The boards themselves don't typically go through that system directly, they get sent as an output from the system, but they aren't treated at all.


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## He's Dead Jim

He's Dead Jim said:


> what kind of temps would be needed to obliterate everything but the metal??


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## scwiers

In practice, you can easily generate those temps in a 'bucket' furnace lined with refractory, fueled with charcoal (2000 F +)

It WILL stink up the neighborhood, and as I've found out through personal experience, the neighbors are going to complain :x . Fully loaded, you might be able to run a batch of 8 lbs. or so of crushed boards, and end up with 2 lbs. or so of a Lead-Tin ingot, with copper mixed in. Only trace PMs.

Now Inco, in Sudbury up north, shoot, they smelt batches of 50 tons of molten metal at a time. Check out their smokestack at

http://en.wikipedia.org/wiki/Inco_Superstack


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## Husker

could this "problem" be solved by ball milling to a very fine powder, and then using a shaker table to separate. At least, this should highly concentrate the heavy metals, and would eliminate 99% of the nastyness of what you would end up incinerating (just a guess, as I have not tried doing this to boards).

Jim.


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## goldsilverpro

Much of the stuff isn't friable. Ball milling, without inceneration would create mush. You wouldn't get powder.


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## Husker

So then without the nasty incineration of the main bulk of it, it sounds like a shaker table would not be of much use. Too bad. They can certainly blow through a LOT of material pretty rapidly.

Is there any certain product (like the solder mask) which is the worst offender, in not being able to get a powder?

H.


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## goldsilverpro

Freezing in nitrogen and then ball milling is supposed to pulverize the non-metallics. There are some patents on it.


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## scwiers

Here's a bucket of crushed powder that I produced by running circuit boards through a ball mill and sieving it. The leftover small pieces of board that don't crush, but were worn 'clean', get leached in a separate bucket. You can clearly see metallics in the bucket. As well, you can see little 'plates' of scum. Actually, they're just bits of powder that tend to clump up in high humidity, much like cake flour.


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## Joe

I've managed to melt down circuit boards in a furnace bucket. The melted metal formed some sort of alloy that looked like a stainless steel to me. I couldn't get anything to dissovle it.


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## Anonymous

Give us some pictures of your new alloy.


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## Anonymous

Joe said:


> I've managed to melt down circuit boards in a furnace bucket.




how clean was the exhaust from melting these boards? were you using charcoal, propane or used oil as a fuel?
just wondering if this could be used in a populated area or if you managed to completely annoy the neighbours?


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## Anonymous

Hey Guy's, 
I'm pretty new to all this stuff, this is my first post. Still trying to figure out if it's worth the time. In response to this post about boards, I've been playing around with some curciut boards. . .experimenting. I cleaned a c/b of all the fingers,and flat packs. The underlying board seemed to be filled with Gold strips under the green mask. I took the board to a friends body shop and sanded the top with a dual action sander (D/A) exposing the Gold runs, this took less than a minute. I then took the boards home and pealed the gold inlays out with a dremel tool, once started you can peal the whole gold inlay out in one shot. the dust from the dremel was filled with gold (or what ever that metal may be, Hopefully Gold) I thought this would use less acid to process then grinding the whole board. I haven't processed anything yet. still playing around with harvesting. being new to this I like hear some feedback on this idea, I probably have the least experience of anyone out there. Oh Yeah, appreciate everyone who has put out information on this sight , THANK YOU. Special Thanks to Lasersteve, Harold_V, ECT. . .
Jeff


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## Anonymous

I have a picture, but can't getted loaded to the site


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## leavemealone

I am sorry to say but 99.9% of the time that will just be copper.A simple test will prove it either way,place some of your tracing in some muratic acid.If it all dissolves then there is no gold.I have about 100 pounds of boards that have all gold tracings,and not one of them is a motherboard.I don't believe I have ever seen a pc motherboard that does have all gold tracings.All of mine are router,server,mainframe,and plug in cards.But don't think that the board is worthless.....on the contrary,there is a plethora of values in it.Recovering them economically is another story.
Johnny


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## Harold_V

ptjetpilot said:


> I have a picture, but can't getted loaded to the site


There are size limitations that prevent the site from accepting oversized pics. Reduce yours to 800 x 600 pixels and it should post. Anything larger spreads text off the screen, which is nothing short of annoying. It is for that reason there are size limitations. 

While you're making adjustments, shrink the file size, too, so those with dial-up connections don't have to wait for an eternity for pics to download. A picture with a file size of 50 kb is more than adequate in most cases, assuming it is not blurred. 

Harold


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## Anonymous

Joe said:


> I've managed to melt down circuit boards in a furnace bucket. The melted metal formed some sort of alloy that looked like a stainless steel to me. I couldn't get anything to dissovle it.


You can pull the silver out by electroplating to steel +copper to copper plates leaving gold +other metals to deal with


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## goldsilverpro

Welcome to the forum, Howard.



> You can pull the silver out by electroplating to steel +copper to copper plates leaving gold +other metals to deal with


What solution are you using?


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## Anonymous

Lino1406 said:


> Are numerous. For example: 1st - incinerate
> 2nd - A/P


#3 electroplating


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## Anonymous

goldsilverpro said:


> Welcome to the forum, Howard.
> 
> 
> 
> 
> You can pull the silver out by electroplating to steel +copper to copper plates leaving gold +other metals to deal with
> 
> 
> 
> What solution are you using?
Click to expand...

Looks like hydracloric+nitric don't know %.


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## Anonymous

ptjetpilot said:


> Hey Guy's,
> I'm pretty new to all this stuff, this is my first post. Still trying to figure out if it's worth the time. In response to this post about boards, I've been playing around with some curciut boards. . .experimenting. I cleaned a c/b of all the fingers,and flat packs. The underlying board seemed to be filled with Gold strips under the green mask. I took the board to a friends body shop and sanded the top with a dual action sander (D/A) exposing the Gold runs, this took less than a minute. I then took the boards home and pealed the gold inlays out with a dremel tool, once started you can peal the whole gold inlay out in one shot. the dust from the dremel was filled with gold (or what ever that metal may be, Hopefully Gold) I thought this would use less acid to process then grinding the whole board. I haven't processed anything yet. still playing around with harvesting. being new to this I like hear some feedback on this idea, I probably have the least experience of anyone out there. Oh Yeah, appreciate everyone who has put out information on this sight , THANK YOU. Special Thanks to Lasersteve, Harold_V, ECT. . .
> Jeff


You could use dessert fox on the dust . Could you post picture of half pealed board.


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## g_axelsson

HowardBlakeney, have you ever used the desert fox system on e-scrap?

Desert fox is a spiral concentrator for placer deposits, not an e-waste refining system. It would be just as useful to e-waste as an air chisel used for removing pins would be to recovering black sand deposits.

Each tool has it's area where you could use it and I'm strongly skeptical to that this is the right area for the desert fox. If you have done it, please give us some more details. Yield numbers, how you did it in details or pictures would be good.

Spectacular claims needs spectacular proofs.

/Göran


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## Anonymous

I borrowed a 3 phase 415V 7.5kW turbo mill with cyclone dust control to powder complete mother boards to about as fine as domestic flour at 10,000 rpm rotor speed. Everything basically disintigrated into grey ultra-fine dust of which I have stock piled maybe 10kg. 

With regard to PM recovery, will a 70% nitric acid leach remove all of the base metals completely?

Is it actually better to use HCl in a closed bath to strip off the solder causing the ICs to drop off then turbo mill these since the copper content on the mother board laminate is quite high? 

Im open to suggestion.


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## LeftyTheBandit

Weird idea that I've been looking into...

Depolymerization of circuit boards.

http://en.wikipedia.org/wiki/Thermal_depolymerization

Place boards in a pressure vessel with water. Heat to 250C to 600psi for 30 minutes. Decompress quickly.

According to wikipedia this will break down complex material and create bio-diesel (Non-metallic s). The heavy metals will be reduced to oxides.

This has been used for medical waste and turkey poo, but it might work for pcb's?


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## Palladium

http://discovermagazine.com/2003/may/featoil/




goldsilverpro said:


> Thermal depolymerization is too damned dangerous for me. I knew a German guy, in Portland, that had spent 10 years working on on a TD process for tires. His yields, when it didn't blow up, were about the same as on the Wiki link. If there is just the faintest leak in the system, the oxygen combines with the evaporated organics. This immediately drives the temp. up and Boom. I've seen several patents for doing X-ray film this way. When phenolic boards were being made, you could supposedly distill off 40%, by weight, phenol oil, which is worth a fortune..
> 
> I've seen a lot of these TD schemes over the years but, no real full-size plants. It sounds like such a good idea.


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## Anonymous

HowardBlakeney said:


> Joe said:
> 
> 
> 
> I've managed to melt down circuit boards in a furnace bucket. The melted metal formed some sort of alloy that looked like a stainless steel to me. I couldn't get anything to dissovle it.
Click to expand...


Crush the metal to powder, treat with a solution of copper sulfate and a little sulfuric (battery acid). the copper will replace most base metals, leaving you a powder that contains copper, and your precious metals, after you have the powder threat with acid peroxide to remove the copper, melt the rest and sell or refine up to you.

JIm


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## Bill R

Back in the early 90s I used to sell circut boards and high end CPUs (the little purple/brown ones with the gold lid and gold legs) and other high grade to an outfit in LA called Electronic Epicenter, the owner Bruce told me that he threw it all in a furnace and melted it into large blocks and that they would drill out a couple grams of metal and have it independently assayed, then buyers from Taiwon would bid on these blocks. Back then Taiwon made all the electronics, now of course its China. My understanding is that China does most of the electronics recycling for the world. There must be some way of cashing in on that cow. I had given up on computer gold for a decade, a damn shame too because I was scrapping 1970s stuff that was awash in gold, but i just wasnt getting what it was worth. If only the internet and this forum where available then! I have been reading this forum every chance I get, Ive been looking for a dependable refinery that will do electronic scrap and not rip me off by keeping 30% of my gold in their flux. So far from what Ive read there aint no such animal, there certainly is a need for one.


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## Anonymous

There's plenty of good reputable refineries Bill.

Which part of the world are you in?

Edit I saw you're in the States!


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## goldsilverpro

spaceships said:


> There's plenty of good reputable refineries Bill.


Maybe in Europe. The US government never cared much whether or not refiners steal from their customers. Our government is 99% for the corporations, 1% for the people. How else would they get as rich as they all seem to do.

In the US, there may be a few honest refiners, but your best bet is to always assume that the buyer or refiner will cheat you if you give him the opportunity, even if he's your best friend or your brother-in-law. So, do everything you can to prevent him from getting to you. The best way to win is to really, really know what your material is worth before striking a deal. The second best way is to make the refiner believe that you know what you've got. They want repeat business. If they see that you don't know much of anything, they will hit you harder. They can tell both when you know and when you don't know.

I guarantee you that, in this business, in the US, there is more crookedness than honesty. There is a tendency for the very big guys to treat you somewhat more fairly than the little guys but all these guides have exceptions.

I have spent time in many, many refineries and could write a book of horror stories of people that were cheated by this industry. I spent about 25 years on the other side of the counter. Although I can't definitely name one, there surely are some refiners who are reasonably honest. However, I will bet my bottom dollar that not one refinery in the US is 100% honest and, if the truth were known, it's probably the same all over the world.

Be a Boy Scout. "Be Prepared" when dealing with a refiner.


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## manchvegassalvage

goldsilverpro said:


> spaceships said:
> 
> 
> 
> There's plenty of good reputable refineries Bill.
> 
> 
> 
> Maybe in Europe. The US government never cared much whether or not refiners steal from their customers. Our government is 99% for the corporations, 1% for the people. How else would they get as rich as they all seem to do.
> 
> In the US, there may be a few honest refiners, but your best bet is to always assume that the buyer or refiner will cheat you if you give him the opportunity, even if he's your best friend or your brother-in-law. So, do everything you can to prevent him from getting to you. The best way to win is to really, really know what your material is worth before striking a deal. The second best way is to make the refiner believe that you know what you've got. They want repeat business. If they see that you don't know much of anything, they will hit you harder. They can tell both when you know and when you don't know.
> 
> I guarantee you that, in this business, in the US, there is more crookedness than honesty. There is a tendency for the very big guys to treat you somewhat more fairly than the little guys but all these guides have exceptions.
> 
> I have spent time in many, many refineries and could write a book of horror stories of people that were cheated by this industry. I spent about 25 years on the other side of the counter. Although I can't definitely name one, there surely are some refiners who are reasonably honest. However, I will bet my bottom dollar that not one refinery in the US is 100% honest and, if the truth were known, it's probably the same all over the world.
> 
> Be a Boy Scout. "Be Prepared" when dealing with a refiner.
Click to expand...



I have workeed in the Recycling feild for close to 15 years now owning my own companies and finnally ending up with The company I currently work for.We are what you would call your all around recycler. Buying and selling Ferrous, Non Ferrous, Auto cores, Catalytic Converters, Ewaste and Precious metals. We are one of the biggest buyers and decanners of Converters in the USA. We have had a relationship with the mill the Processes our catalyst for over ten years and five years with the mill that processes our Circuit boards and Misc Ewaste. 

In that time during the infancy of our success we filtered through many refiners and Mills until we ended up with the two mills we currently use and will probbally always use because of the fact that EVERY other mill and refiner is in one way or another Dishonest, Crooked, Liars..etc...etc...

I will not mention any names of who is good or bad but i will say this that the mill we currently use for our Ewaste is based in Belgium :roll: and Has tried and succeeded at being as automated and honest as possible by taking out as much as the human element as possible during there process. I can not vouch for anything other then how they have treated us over the years but i will say that they have been as transparent and as helpfull as they could possibly be. If they had the technology to let our brains access their system so we could see exactly what they are doing and thinking at all times they would provide it.

The rest of the Mills and refiners we have used are just the opposite.


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## pgms4me

leavemealone said:


> I am sorry to say but 99.9% of the time that will just be copper.A simple test will prove it either way,place some of your tracing in some muratic acid.If it all dissolves then there is no gold.I have about 100 pounds of boards that have all gold tracings,and not one of them is a motherboard.I don't believe I have ever seen a pc motherboard that does have all gold tracings.All of mine are router,server,mainframe,and plug in cards.But don't think that the board is worthless.....on the contrary,there is a plethora of values in it.Recovering them economically is another story.
> Johnny


hello Johnny: Just wanted to let you know that all HP hi end servers from the mid nineties(especially the 9000 and L 2000 series have 100% of all traces on the motherboard and backplane boards even all the traces under the solder mask are gold plated.Hope you get to find some Donn


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## gaurav_347

so electrolysis would be a good option if you are processing such mixed metal fractions on larger scale say like 500kg per day?


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## ericrm

manchvegassalvage said:


> I will not mention any names of who is good or bad


you see, thats is kind of problematic because since you dont say who they are ,the good one doesnt get more customer so they dont get more power for being honest, but the disonest one you alow them to get customer by not knowing they are crooks and doing so you alow them to keep power and stay in business...
i know it must have been proposed pretty often but why dont we make a tread about refinner good and bad...


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## Harold_V

Moderators are, right now, considering a sticky that would list those who have been dishonest with readers. 

Those of you who have had negative experiences with others on this board need to speak up. To not do so simply enables those who are less than honest to succeed. Expose them, but do it wihout rancor. Describe what happened, in perfect detail. Do it politely, sticking to the facts. Do not attempt to lead readers----we are interested in nothing more than the truth, which often is far more damning than anything one might conjure in one's mind. 

If you have something to report, but prefer to not do so publicly, send a PM to a moderator. Make your comments clear, and provide any data at your disposal to support your position. 

Harold


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## 9kuuby9

manchvegassalvage said:


> I will not mention any names of who is good or bad but i will say this that the mill we currently use for our Ewaste is based in Belgium :roll:



Is it Umicore? I heard that they're actually not that good. Just curious because I'm from Belgium too. 8) 

And I also think that Any person/company who deals in a doggy manner has to be exposed to limit the possible casualties.

The bad side has to be exposed in order to be known.


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## kjavanb123

complex-chemistry said:


> I borrowed a 3 phase 415V 7.5kW turbo mill with cyclone dust control to powder complete mother boards to about as fine as domestic flour at 10,000 rpm rotor speed. Everything basically disintigrated into grey ultra-fine dust of which I have stock piled maybe 10kg.
> 
> With regard to PM recovery, will a 70% nitric acid leach remove all of the base metals completely?
> 
> Is it actually better to use HCl in a closed bath to strip off the solder causing the ICs to drop off then turbo mill these since the copper content on the mother board laminate is quite high?
> 
> Im open to suggestion.



Really strange, practically any posts related to using mechanical separation using shaking tables on pulverized materials has been to dead ends, and no follow up, is it because the experience was not successful? I am building a shaker table and grinder is already in place, to use wave table to separate different metals.

Thanks
Kevin


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