Geo
Well-known member
bobsmith said:
your general location may help.
Palladium recovery from Monolithic Ceramic Capacitors
- Thread starter samuel-a
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your general location may help.
Geo
Well-known member
most refiners deal with palladium on a daily basis. i wouldnt think the material it came from would make much of a difference unless it was something like whole circuit boards. im sure theres a few that will process even those.
Hi, sorry if any thread necromancy is unintentionally being proposed, but I've been aware of a 1 to 1 mix of chlorox bleach and hydrochloric acid is used as an alternative to aqua regia, and I don't have access to nitric acid, so would anyone have any evidence or prediction having to do with substituting aqua regia with hcl/bleach?
They will both dissolve gold, but HCl/Cl is much slower, so it's usually reserved for dissolving materials with high surface areas like foils and powders. I believe lazersteve has posted some information on the ratios. A search with him as the author might get you some more specific information.
Dave
Dave
Alentia
Well-known member
Sam,
Are there any reason other than separation of values physically removing MLCC from boards instead of processing whole boards in CuCl2?
In CuCl2 solution they fall off themselves and than processing it together with foils save lots of time while doing chemical separation of Au and Pd instead of physical.
Are there any reason other than separation of values physically removing MLCC from boards instead of processing whole boards in CuCl2?
In CuCl2 solution they fall off themselves and than processing it together with foils save lots of time while doing chemical separation of Au and Pd instead of physical.
bswartzwelder
Well-known member
- Joined
- Oct 24, 2011
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I believe that processing whole boards will destroy the solution by the addition of lead or tin from the solder. If I am wrong, someone will correct me. I once thought of this myself. Having said that, how much different is it to have waste HCl with lead/tin, waste HNO3 with lead/tin, or waste CuCl with lead/tin?
A
Anonymous
Guest
Yeah I was under the impression that the best way with MLCC was to soak in HCl to get rid of the solder components and then incinerate to get rid of any traces of HCl.
Then you're left with bare MLCC and you dont end up making silver Chloride when you start processing them in Nitric.
Obviously I could be wrong and if so, I'm sure somebody will be along shortly to tell me 8)
Then you're left with bare MLCC and you dont end up making silver Chloride when you start processing them in Nitric.
Obviously I could be wrong and if so, I'm sure somebody will be along shortly to tell me 8)
Most economical way to remove MLCCs is mechanically, using a sharp hardened tool like a large flat screwdriver, chisel etc.
You can focus on the larger case MLCCs, since the small ones really don´t add up to a worthy weight. Doing so will cost you only seconds for each board.
Using HCl will result in a messy solution that has to be taken care of, plus losses due to silverchloride.
Using heat is another way, but slower and consumes energy=money. Also a lot of solder tin will end up on the MLCCs.
I know one treis to recover in a most fancy way, but after trying out several techniques, the manual one seems to be the most economical to me. In addition it can be performed my any person (grandma,grandpa etc.. :lol: .) and without any chemicals, fume, danger and waste.
You can focus on the larger case MLCCs, since the small ones really don´t add up to a worthy weight. Doing so will cost you only seconds for each board.
Using HCl will result in a messy solution that has to be taken care of, plus losses due to silverchloride.
Using heat is another way, but slower and consumes energy=money. Also a lot of solder tin will end up on the MLCCs.
I know one treis to recover in a most fancy way, but after trying out several techniques, the manual one seems to be the most economical to me. In addition it can be performed my any person (grandma,grandpa etc.. :lol: .) and without any chemicals, fume, danger and waste.
A
Anonymous
Guest
Marcel enough of the little ones do add up to a worthy weight. Most people don't get to see Kg of these things so I really wouldn't recommend wasting them.
1000G of small ones yields exactly the same as 1000G of big ones. For clarity Marcel I was referring to cleaning them in my last post, not removing them from the boards. I wouldn't process them on the boards either I agree.
However neither would I want the tin in the solder to be in Nitric acid, it makes a horrendous pasty mess. I'd rather deal with the Silver Chloride
1000G of small ones yields exactly the same as 1000G of big ones. For clarity Marcel I was referring to cleaning them in my last post, not removing them from the boards. I wouldn't process them on the boards either I agree.
However neither would I want the tin in the solder to be in Nitric acid, it makes a horrendous pasty mess. I'd rather deal with the Silver Chloride
9kuuby9
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One could use excess hot sodium hydroxide to dissolve the tin and lead. heat up excess sodium hydroxide in a 304 or 316 stainless steel vessel to a temperature of 80°C and slowly add the MLCC's to dissolve the solder. Let the MLCC's sit in the solution for at least 1h+
This should solve the solder problem, One should wash the remnants of the MLCC's in hot distilled water (x3) and proceed with hot nitric leeches to recover the Silver from the MLCC's, note that also some Pd will be dissolved by this process but not much. (if the MLCC's do contain Pd)
Caution! Do not use Glass, The sodium hydroxide will eat through the glass in no time. And also handle the sodium hydroxide with care and avoid any splashing as it causes severe burns!
This should solve the solder problem, One should wash the remnants of the MLCC's in hot distilled water (x3) and proceed with hot nitric leeches to recover the Silver from the MLCC's, note that also some Pd will be dissolved by this process but not much. (if the MLCC's do contain Pd)
Caution! Do not use Glass, The sodium hydroxide will eat through the glass in no time. And also handle the sodium hydroxide with care and avoid any splashing as it causes severe burns!
A
Anonymous
Guest
It's a shame I don't have the kit to do that mate 
Alentia
Well-known member
Marcel said:
Not sure how it can be economical trying to remove MLCC from over 120lb of hard drive boards by hand. That may take days...
A
Anonymous
Guest
Alentia said:
Nah not at all!
Alentia
Well-known member
spaceships said:
Months?
niteliteone
Well-known member
You'll probably quit before you finish them, so, Forever :lol:Alentia said:
A
Anonymous
Guest
Maybe we're talking about different things here but if you're talking about removing MLCC from a HDD board using a chisel it's a lot less work and far more rewarding than say taking pins out of the end of printer leads.
I've done it myself before, but I'll have a go this weekend with a few samples and see how long it takes and post the results gents.
It's certainly not days upon days or months 8)
I've done it myself before, but I'll have a go this weekend with a few samples and see how long it takes and post the results gents.
It's certainly not days upon days or months 8)
bswartzwelder
Well-known member
- Joined
- Oct 24, 2011
- Messages
- 660
If you use a hot NaOH bath, and solder mask on the circuit boards will also be removed. This will expose ALL the copper traces. Could be a blessing in disguise since more than one member has found boards where the traces were gold plated.
Using something sharp like a chisel or sharpened screwdriver will remove the components. You will have to hold the boards with one hand or some type of clamp or fixture and then apply the tool.
For my own personal preference, I prefer a heated sand bath. I place a 9 inch square cake pan on a hotplate and half fill it with clean white playground sand that has had any of the larger grains sifted out of it. Place the board, solder side down on the hot sand and kinda wiggle it so it makes good contact with the sand. After 10 to 15 seconds, pull the board out with pliers and rap its edge down onto a solid surface. I use a Teflon covered cookie sheet with a lip all the way around it. The components usually all come off cleanly and easily. Any components left on the board get another treatment with the sand bath. If you are doing cell phone boards, you can put several in your sand bath at once so that there are always some ready to take out. You usually don't do much damage to the components and you get to save a lot of solder which could contain silver. Make sure you do it outside. The fumes would most likely be toxic and a little breeze will be your best friend.
You need to make sure the hot plate gets hot enough to melt solder. I use an older model I bought at WalMart for less than $20 and it does a great job. However, to reduce liability from lawsuits, many hotplates now being sold do not get hot enough to melt solder. You could also check out thrift shops and flea markets. There is no correct or incorrect method. Whatever works for you is the correct method. Using a heated sand bath does not produce liquid waste which will require treatment before disposal. Let us know how you do it.
There have been literally tons of posts on how others have approached this problem. Right now, I have in excess of 6 five gallon buckets filled with cell phone circuit boards which need to be depopulated. I know it will be a long, time consuming task, but now that I'm retired, I can do it whenever the weather and the aches and pains in my old joints allow.
Bert
Using something sharp like a chisel or sharpened screwdriver will remove the components. You will have to hold the boards with one hand or some type of clamp or fixture and then apply the tool.
For my own personal preference, I prefer a heated sand bath. I place a 9 inch square cake pan on a hotplate and half fill it with clean white playground sand that has had any of the larger grains sifted out of it. Place the board, solder side down on the hot sand and kinda wiggle it so it makes good contact with the sand. After 10 to 15 seconds, pull the board out with pliers and rap its edge down onto a solid surface. I use a Teflon covered cookie sheet with a lip all the way around it. The components usually all come off cleanly and easily. Any components left on the board get another treatment with the sand bath. If you are doing cell phone boards, you can put several in your sand bath at once so that there are always some ready to take out. You usually don't do much damage to the components and you get to save a lot of solder which could contain silver. Make sure you do it outside. The fumes would most likely be toxic and a little breeze will be your best friend.
You need to make sure the hot plate gets hot enough to melt solder. I use an older model I bought at WalMart for less than $20 and it does a great job. However, to reduce liability from lawsuits, many hotplates now being sold do not get hot enough to melt solder. You could also check out thrift shops and flea markets. There is no correct or incorrect method. Whatever works for you is the correct method. Using a heated sand bath does not produce liquid waste which will require treatment before disposal. Let us know how you do it.
There have been literally tons of posts on how others have approached this problem. Right now, I have in excess of 6 five gallon buckets filled with cell phone circuit boards which need to be depopulated. I know it will be a long, time consuming task, but now that I'm retired, I can do it whenever the weather and the aches and pains in my old joints allow.
Bert
