stripping base metals and depopulating boards

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rasanders22

Well-known member
Joined
Feb 14, 2011
Messages
137
I have quiet a few cell phone boards that have to be stripped. Can I just soak them in HCl which would remove all the solder? All he base metals would be dissolved and the surface mounted devices would be removed too.
 
When i do boards i take any steel objects off as well as any plastic, mainly white plastic or aluminium on so on. Then i put them in a 5 gallon bucket in your case and sit them in the sun. No air, no stirring, no H2O2 or oxidizer in any way. After about 2-3 days you can take a plastic putty knife and scrap loose what don't fall off. I then take everything that came off the boards, trash and all and run it thru ap. What's left should be a collection of gold foils and some palladium in the bottom with what looks like sand. This is from the Mono cap and maybe some silver chloride in the mix. I then filter the ap thru a Charmin plug in a 2 liter cut off soda bottle. Rinse with water. Leave all the trash in the bottle this is your gold, pd, silver. Then put the cap on the soda bottle. Add hcl and bleach. Immediately swirl and let set maybe 5 minutes. Remove lid and drain. I purposely do this so i make sure i have an excess of oxidizer just in case their may be something in there that is left with base metals, but there shouldn't be. Heat the solution to drive off excess cl and drop with your choice of precipitant. I then add the rest to the stock pot to cement any pd values because they are in small in size and not worth going after with another process. The filter and bottle will hold any silver chloride which can be separated with a ammonium rise to separate it from the trash in the filter.
 
So if I understand you correctly....
1. Strip steel, aluminum, and plastic off the boards. (Already done)
2. Place the boards in Hcl in a sealed bucket for 2-3 days.
3. After 2-3 days manually strip the stuff that doesn't come off.
4. Run all the parts that came off through AP. (Does this include the boards or should I run them seperatly?). Then filter AP through charmin plug.
5. Add AC to dissolve gold and leave pgm's and AgCl.
6. Filter AuCl through charmin plug.
7. Precipitate Au with smb.
8. The rest is a mix of AgCl and pgm's. Set those aside for a day when I have more.

Should I worry about solids left in the filter?
Should I pull out things like bga's and set those aside with my other chips for a day when I can process those?
 
Afternoon – please excuse my ignorance, but what does leaving your scrap in a sealed bucket out side do to make it easier to remove the bits?

Cheers

Deano
 
rasanders22 said:
So if I understand you correctly....
1. Strip steel, aluminum, and plastic off the boards. (Already done)
2. Place the boards in Hcl in a sealed bucket for 2-3 days.
3. After 2-3 days manually strip the stuff that doesn't come off.
4. Run all the parts that came off through AP. (Does this include the boards or should I run them seperatly?). Then filter AP through charmin plug.
5. Add AC to dissolve gold and leave pgm's and AgCl.
6. Filter AuCl through charmin plug.
7. Precipitate Au with smb.
8. The rest is a mix of AgCl and pgm's. Set those aside for a day when I have more.

Should I worry about solids left in the filter?
Should I pull out things like bga's and set those aside with my other chips for a day when I can process those?

When you do # 5 the pgm's will dissolve also with the gold.
You will recover these after you drop your gold. The way to do this is just to add a piece of copper to the spent solution after you drop your gold. The palladium and if you have platinum in there will cement to the copper. Any silver chloride will be trapped in the filter residues with your trash and chip packages. You can remove the silver chloride with an ammonia rinse and then you can add hcl to the ammonia to re precipitate the silver as a chloride. Then the only thing you are left with is the stripped chips which you can ball mill later. Store them in a gallon zip lock baggy until you have enough to process. Throw the charmin plug in with the used chips.

I then take the stripped boards and run them in some warm sodium hydroxide to remove the green mask and process them in ap also. When your cleaning the parts from step #3 the easiest way i found to do it is take the boards out of the hcl and let them drain for a couple of minutes in a spaghetti strainer. Then i take them and hold them under the water in a 5 gallon bucket with nothing but clean water in it ( about half full ). i take a 1 in putty scraper and holding the board under water i scrap off what didn't come off. Don't worry about any green mask that might come off at this point. Let the stuff settle over night and decant, not filter off the excess water. add everything from the bucket to the ap mix. You will do the same thing with the other 5 gallon bucket with the hcl in it. When i decant the 5 gallon buckets i use a piece of 3/8 in aquarium hose and a pair of hemostats so i can pinch the hose and control the flow. I filter the liquids thru a couple of coffee filter just to make sure i don't loose anything. Don't let the hose touch the bottom of the bucket or you will suck up trash and clog your filter. The filter is only a safety precaution.
 
NoIdea said:
Afternoon – please excuse my ignorance, but what does leaving your scrap in a sealed bucket out side do to make it easier to remove the bits?

Cheers

Deano


It removes the solder, tin, lead and other base metals, but not the copper because their is no oxidizer. Hcl alone will not dissolve copper. That’s why we use H2O2 or air to oxidizer copper to copper oxide which hcl will dissolve. If you leave it longer than 2-3 days the heat and oxidizer from the air will start to attack your copper. You don't want this yet. It will also make the green mask come off which you don't want yet if you leave it longer. If you do it right and keep the oxidizer out of the equation you will be surprised at how many boards you can run through the hcl to remove the solder. When you get air in there it just screws it all up. This is a three step recovery process. Not refining.
 
butcher said:
I assumed they were in acid, sealed from animals or what not.

I have cats and cats are curious. :p

It sort of goes unspoken, but yeah you need a lid on there to stop fresh air from entering the solution once the hcl absorbs what is trapped in the bucket when you first seal it up. I said don't stir earlier. What i meant was with the lid off and exposed to air. With the lid on and sealed you can give it a swirl every now and then to help dislodge the components from the board. It's all about the air.
 
After searching and searching I cam upon this thread. OH I LOVE YOU ALL!

Let me say it proud, I am a big time newb. I am an avid prospector but am starting to look at these things called cell phones. I have well over a 300 boards and have access to 1000's. If I follow the above steps first with the parts that came off in the HCL, then with the boards all using AP, I should have success?

I do not know what a charmin plug is? Or what it does? How does this filtering differ then Steve's video?

Thanks a-lot and WoW what a great site with good people helping each other.

Chris
 
A charmin plug is a piece of toilet paper, used as a filter. You insert it in a funnel, similar to the one in the pic. (in the pic. I used a piece of fiber glass insulation).

Phil
 

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I also have access to a 600lb a month lot of mixed PC cards, memory cards, IDE cards, and etc, also 5 tons of motherboards, please kindly if this method can be used to strip the boards at once. then process them later.

Regards,
Kevin
 
kjavanb123 said:
I also have access to a 600lb a month lot of mixed PC cards, memory cards, IDE cards, and etc, also 5 tons of motherboards, please kindly if this method can be used to strip the boards at once. then process them later.

Regards,
Kevin

some of the PVC sockets on motherboards are soluble in hcl in will dissolve.this dissolved plastic does not go into solution but rather turns into a gooey mess. some sockets will hold up to the acid and others will fail. it will cover components and theres no good way to remove it after it gets in this state.
 
You have access to all this and you want to throw it into a pot? Cherry pick the best and make cash with the rest. That much could be a full time monthly income per month for most.
 
kjavanb123 said:
I also have access to a 600lb a month lot of mixed PC cards, memory cards, IDE cards, and etc, also 5 tons of motherboards, please kindly if this method can be used to strip the boards at once. then process them later.

Regards,
Kevin

I think if you want to use this method on multi ton quanitities of boards, you are basically on your own, because no one here has done that, and there are likely good reasons for that. I think you'll be in for lots of surprises along the way if you can get it to work at all. I hope that your venture is working out for you, truely i do, but maybe you could have figured out what to do with the boards before you bought the industrial building :shock:
 
All,

This is a clearifcation on this matter, first of all, I did not buy this facility, I basically rented this unit from the local government that they set it up and lend to a school grad to work on it and recycle and refine metals from e waste. They couldnt handle it, only produced few grams of copper and tin, state paid for everything, shredder, an electrowinning unit, crane, a CRT recycling unit, and many more, since a year ago the facility had been abandoned due to lack of knowledge, until I showed them my gold silver recovered from CPUs and won the auction, they litterly gave me 18 MT of mixed e waste for free and asked to just run the place, so far I cleaned up the mix wastes, and once I could produce I will be giving an stream of e waste government collects on national scale which is 30 tons a month just computer motherboards alone, along maybe a ton or more of mixed cards, and other electronic junks.
That is why I travled to Singapore to meet up with this consultant who has been with the only recycling and refining company there to give me some guides on how to run things on commercial scales. He suggested to use air chisel and cheap labor locally to basically cherry pick the gold plated and gold items, then process them separately.
I didnt feel like he knows as much as some of the members here, so I even asked the forum for a consultant to provide some support and even be open to some sort of joint venture, where he can help me with processing while I can get my hands on a large volume of e waste.
The only trick about the facility here is I can not just sell the boards to outside, all e waste has to be recycled and refined here locally, the stripped boards, dteel, plastics and etc can be sold outside though.
Here is the picture of plant before and after some clean up,
image.jpg

And this is a week later, it is much cleaner right now, also found another 20 lbs of mixed cards today,
image.jpg

One thing that really gets me going is the fact, the volume of materials we can get, also the price we pay for that volume is very cheap, but the catch is we have to refine in house, so again if any of you pros are interested in this please contact me in PM to go over details.

Regards,
Kevin
 
Looks like a lot of work, with a big reward in the end. I'd like to happen on a deal like that, be my retirement job.
 
Ok, I get it better now, sorry if I was dismissive, or disrespectful. I would consider talking with the people who are setting the conditions and seeing if you could be allowed to export the boards whole with the condition that a great part of the profit be put towards more equipment and practice on treating the materials. Its a nice idea for keeping workers employed, the in house recovery and concentration, but it's likely a ways off till you have everything ironed out and it doesn't really seem like a totally fair expectation on their part, but maybe it's not something that can be argued.

It's a unique and interesting experience for you, and it will be a big feather in your cap to get it working!
 
It is an option provided by them to process low grade boards, or export them. However, I think there are some low and mid yield ICs on those low grade boards that once the volume is large it can add up, so I have cherry picked them as much as we can.
Our main focus would be computer motherboards, fingers, cards and copper wires.

Your assistance snd consulting won't be under estimated.

Thanks
Kevin
 
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