[moved] Precious metal recovery
badastronaut, Mon Jul 10 2006, 01:53PMHas anyone attempted to recover precious metals like gold, silver, and platinum group metals from e-waste and other trash?
Apparently, electronic connectors are often gold plated, and with all the old computers and cell phones thrown away, the amount of gold for recovery is significant.
Catalytic converters contain platinum, palladium, and rhodium with rhodium valued at over 4000 USD per troy ounce. Hard drive disks also contain platinum.
My first and only current attempt at metal recovery was a little experiment where I crushed some gold plated finger stock from a cell phone and dissolved the base metal with ferric chloride. At two days, this process is still incomplete as I should have ground up the metal more. Still, I can see a bunch of gold flakes in the solution.
There are several methods of recovery, virtually none of them safe. Gold can be dissolved with aqua regia and precipitated, dissolved with cyanide, or dissolved with some sort of thiosulfate which there is little information on.
For catalytic converters, the platinum group metals could be dissolved with aqua regia, but there isn't much specific information on the process.
Even though all of this probably won't even yield a nugget the size of a grain of rice, it still seems fun.
Re: [moved] Precious metal recovery
Desmogod, Tue Jul 11 2006, 02:14AM
May be better suited to the chemistry forum?
Desmogod, Tue Jul 11 2006, 02:14AM
May be better suited to the chemistry forum?
Re: [moved] Precious metal recovery
Pete, Thu Jul 13 2006, 09:07AM
I asked the same question to the group on the old 4hv board. It really seems that for the precious metals, aqua regia is the way to go. Here is the thread. I'll cross my fingers in hopes that the link works.
http://old.4hv.org/index.php?board=8;action=display;threadid=5436
Pete
Pete, Thu Jul 13 2006, 09:07AM
I asked the same question to the group on the old 4hv board. It really seems that for the precious metals, aqua regia is the way to go. Here is the thread. I'll cross my fingers in hopes that the link works.
http://old.4hv.org/index.php?board=8;action=display;threadid=5436
Pete
Re: [moved] Precious metal recovery
badastronaut, Thu Jul 13 2006, 03:37PM
That's very interesting... Did you ever attempt to recover the platinum from those plastic things? One thing to note is that platinum only dissolves in aqua regia at near boiling temperatures.
I think they still do use platinum in hard disk platters.
badastronaut, Thu Jul 13 2006, 03:37PM
That's very interesting... Did you ever attempt to recover the platinum from those plastic things? One thing to note is that platinum only dissolves in aqua regia at near boiling temperatures.
I think they still do use platinum in hard disk platters.
Re: [moved] Precious metal recovery
Pete, Thu Jul 13 2006, 08:58PM
No. I haven't done anything with them yet. I have freinds collecting them for me and every month I get a handful. I'm a natural packrat and when I get enough and/or Wife complains about having this useless junk laying around, I hope to get to it. :)
Pete, Thu Jul 13 2006, 08:58PM
No. I haven't done anything with them yet. I have freinds collecting them for me and every month I get a handful. I'm a natural packrat and when I get enough and/or Wife complains about having this useless junk laying around, I hope to get to it. :)
Re: [moved] Precious metal recovery
badastronaut, Thu Jul 20 2006, 11:27PM
Doing a bit of reading, it seams that refining platinum into a solid ingot is very difficult due to its high melting point. Gold has a much much lower melting point.
Some statistics:
Gold is worth a little more than $20 per gram.
Twenty 486 cpu's weigh about a pound and can yield a total of 3-3.5 grams of gold. Pentium cpu's contain half that amount.
An average gold plated pin clipped off a pcb weighs about .05 grams and can contain about .25-2% gold.
badastronaut, Thu Jul 20 2006, 11:27PM
Doing a bit of reading, it seams that refining platinum into a solid ingot is very difficult due to its high melting point. Gold has a much much lower melting point.
Some statistics:
Gold is worth a little more than $20 per gram.
Twenty 486 cpu's weigh about a pound and can yield a total of 3-3.5 grams of gold. Pentium cpu's contain half that amount.
An average gold plated pin clipped off a pcb weighs about .05 grams and can contain about .25-2% gold.
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