Non-Chemical stripping base metals and depopulating boards

[rewalston]

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.

Sounds like a good way to collect silver as a chloride if you don't have nitrates to work with.
Rusty

 

[rewalston]

A quick question about the HCl originally used to depopulate the boards. Once it's reached it's usefulness, does it go to the stockpot or the waste pot? I know you don't want to use it for AP.

Rusty

 

[kernels]

Straight to the waste, very unlikely to be any PMs in solution as you have basically made a large quantity of Stannous Chloride.

 

[rewalston]

Straight to the waste, very unlikely to be any PMs in solution as you have basically made a large quantity of Stannous Chloride.

That's what I thought but I figured I'd better check first. Don't need to be tossing anything that might have something else in it.

Rusty

 

[rewalston]

What would be a suitable container to collect and accumulate AgCl?

Rusty

 

[Grelko]

What would be a suitable container to collect and accumulate AgCl?

Rusty

I'm not sure of certain types of plastic, others can help with this. A glass jar or crock should be ok.


Hoke's page 49 (Page 48 bottom, saving the silver) She says to leave it in the "crock", and another part says about having it in the dark.

How would drying out the silver chloride, complicate treatment later on?

If you let it dry, it forms a very strong crystalline matrix that will make further processing more difficult.

http://goldrefiningforum.com/phpBB3/viewtopic.php?f=61&t=23226&start=30 Page 2, Frugal was giving me tips about my button.


Use a dark colored bottle, so that the AgCl doesn't break down into elemental silver and Cl gas. https://socratic.org/questions/why-do-we-store-silver-chloride-in-dark-coloured-bottle

On a side note , if you keep it wet, don't keep it in a mason jar, in sunlight. It will slowly eat through the metal lid.

 

[4metals]

I always prefer a good 5 gallon bucket with a secure lid. This is placed under a bench or shelf away from direct bright light and it should suffice.

The reason I prefer the 5 gallon bucket is I have a spreadsheet that I developed to determine the quantity of 50% caustic and Karo syrup to add based on the depth of the silver chlorides in a 5 gallon bucket, so when the bucket starts filling up, stick in a plastic ruler and put the depth in inches into the spreadsheet and it tells you how much of each to use.

 

[rewalston]

I always prefer a good 5 gallon bucket with a secure lid. This is placed under a bench or shelf away from direct bright light and it should suffice.

The reason I prefer the 5 gallon bucket is I have a spreadsheet that I developed to determine the quantity of 50% caustic and Karo syrup to add based on the depth of the silver chlorides in a 5 gallon bucket, so when the bucket starts filling up, stick in a plastic ruler and put the depth in inches into the spreadsheet and it tells you how much of each to use.

A 5 gal bucket sounds like a good option, it will take a long time for me to collect enough AgCl to fill the bucket. I don't know if we have Karo here in Ontario, but we do have Golden Syrup which I believe is basically the same thing. I'll have to pick up another bucket to dedicate to that. I have 4 of them, but they are for different things in reclaiming and waste treatment. Thank you.
Rusty

 

[4metals]

Any corn syrup will do the trick. When you are ready let me know and I'll post the spreadsheet to make it easier for you.

 

[rewalston]

Any corn syrup will do the trick. When you are ready let me know and I'll post the spreadsheet to make it easier for you.

Thanks 4metals, I'll do that. Right now I'm just getting ready to depopulate some boards. I have to wait to get some more NaOH to remove the solder mask on a few of the boards before I start doing any recovery.
Rusty

 

[Grelko]

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?

Since I used a hammer and chisel to depopulate my boards, I can just skip to number 4 and proceed from there. I'm taking out the plastic "pin holders etc", steel and aluminum at the moment. The boards will be done at another time.

Edit - Switched question mark to a period. It wasn't supposed to be in the form of a question.

 

[upcyclist]

I always prefer a good 5 gallon bucket with a secure lid. This is placed under a bench or shelf away from direct bright light and it should suffice.

The reason I prefer the 5 gallon bucket is I have a spreadsheet that I developed to determine the quantity of 50% caustic and Karo syrup to add based on the depth of the silver chlorides in a 5 gallon bucket, so when the bucket starts filling up, stick in a plastic ruler and put the depth in inches into the spreadsheet and it tells you how much of each to use.

Genius!

I use a quart mason jar for mine--with a plastic lid. You can buy a box of 12 plastic mason jar lids for a few bucks at walmart in the canning section. I love 'em--they're great for storing, but of course are horrible reaction and heating vessels. I also use 'em to store some dry chems, like copperas, that tend to show up in cheap ziplock bags.

 

[worldavi]

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.

I dont get this.....You are saying that the resistors and IC chips on the board just fall of after a few days in the sun??. Remember, this topic is "depopulating" boards. what about the circuit traces that are plated gold?

 

[Palladium]

hcl + sun. The gold traces that are left on the board can be run in ap to recover any gold foils or you can use ar to dissolve the traces that are left. It's all according to the materials or the results you are trying to achieve.

 

[rewalston]

hcl + sun. The gold traces that are left on the board can be run in ap to recover any gold foils or you can use ar to dissolve the traces that are left. It's all according to the materials or the results you are trying to achieve.

What if there is water in the equation? With so much tin in solution if it accidentally dissolved some gold because of the water how would you get it back?
Rusty

 

[Grelko]

]
What if there is water in the equation? With so much tin in solution if it accidentally dissolved some gold because of the water how would you get it back?
Rusty

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http://goldrefiningforum.com/~goldrefi/phpBB3/viewtopic.php?t=13250 This link deals with silver+ tin, but it's still about metastannic.

According to an older text I found in google books Incineration to red heat converts the metastannic acid (insoluble in all acids and bases) to tin oxide, soluble in concentrated HCl and H2SO4.

Edit - From reading about metastannic acid over the last hour or so, it seems easiest to just incinerate to red heat, then redissolve in HCl.

Edit again - If it's in AP, just saturate the solution with something higher in reactivity than gold (ex. copper), it'll push the gold out.

Page 699-700
"Metastannic acid is freely soluble in potassic and sodic hydrates, as well as in solutions of their carbonates..."
https://books.google.com/books?id=rIgMAQAAIAAJ&pg=PA699&lpg=PA699&dq=metastannic+solubility&source=bl&ots=B6ZLqte0FT&sig=OFcHsBtAafHk-kNr82pXIJ6Jsx8&hl=en&sa=X&ved=0ahUKEwjjvLGS1Y3OAhWEeSYKHdfDBIAQ6AEIRzAG#v=onepage&q=metastannic%20solubility&f=false

MSDS, soluble in excessive sodium hydroxide
http://www.showakako.co.jp/po/assets/files/SDS-20160708/Inorganic%20Chemicals/SDS-G1016E%20Metastannic%20acid%20EN.pdf

 

[upcyclist]

What if there is water in the equation? With so much tin in solution if it accidentally dissolved some gold because of the water how would you get it back?

Stannous chloride turns AgCl into colloidal gold, right? So it shouldn't make it past the Charmin plug, right?

Also, even if the chlorine in your tap water is somehow enough of an oxidant to dissolve some gold, it also has to get past every other metal in the reactivity table above gold. Since we're talking about depopulating boards here, I wouldn't think that very likely.

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[Topher_osAUrus]

What if there is water in the equation? With so much tin in solution if it accidentally dissolved some gold because of the water how would you get it back?

Stannous chloride turns AgCl into colloidal gold, right? So it shouldn't make it past the Charmin plug, right?

Also, even if the chlorine in your tap water is somehow enough of an oxidant to dissolve some gold, it also has to get past every other metal in the reactivity table above gold. Since we're talking about depopulating boards here, I wouldn't think that very likely.

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It doesnt turn silver chloride (AgCl) into colloidal gold, but for auric chloride it does

 

[rewalston]

I have been using my crockpot to depopulate the boards I have. I ran out of HCl so I added water approx 50/50. No head room to speak of in the crockpot. I heated it up for about 4 hours and then shut it off and let it set overnight to work it's magic. I have to redo some of the boards as all the solder hasn't been removed. I can see a lot of tiny needles (metallic) in the solution and a lot of blackish powder in the solution. I'm assuming that the needles I'm seeing could be tin, but I'm not sure. It does appear that some of the gold was removed from some finger boards that were in there. I still have about 1/4 of the boards to redo, not heating this time, I'll just let it set for another day or two, also some BGA chips that the solder hasn't come all the way off yet. When it's all done I'll filter out the components and boards and then run it through a charmon plug to collect the powders. Not sure with tin in solution to see if there's any gold as well. I don't know yet if there is any silver in there yet or not, don't see any white precip.

 

[upcyclist]

What if there is water in the equation? With so much tin in solution if it accidentally dissolved some gold because of the water how would you get it back?

Stannous chloride turns AgCl into colloidal gold, right? So it shouldn't make it past the Charmin plug, right?

Also, even if the chlorine in your tap water is somehow enough of an oxidant to dissolve some gold, it also has to get past every other metal in the reactivity table above gold. Since we're talking about depopulating boards here, I wouldn't think that very likely.

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It doesnt turn silver chloride (AgCl) into colloidal gold, but for auric chloride it does

Crap, sorry. Autocorrect nailed me and I didn't catch it. I meant (and originally typed) AuCl.

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