alfadriver wrote:
The PCBs- before melting boards to extract the gold, copper, and other metals in them- look into the refining of the raw ore first. Not sure if it's possible on a small scale- but grind those parts up small enough, and it's not that different than raw ore. Which is one thing I've never figured out why you don't see that for parts recycling.
At least from all I've been reading lately, heat doesn't do the boards much good. BUT bleach and muriatic acid combine to do a fantastic job of separating the gold from the boards. Guessing on my part, but the gold flake may be too thin and fragile to just melt off(***). BGA chips on the other hand, burn up to a fine ash that does contain a bit of gold, and yes that could be a bit hazardous to burn. A couple of 5 gallon buckets, an air pump, and something like Urea to neutralize the acid when it's done makes it surprisingly easy to chemically separate the good from the bad, then smelt as needed.
General consensus across YouTube consisting of scientists and chem majors to red necks, was a pound of circuit board fingers, the part on RAM and similar that plugs into the motherboard, will leave you around 1 gram of roughly 18K gold after some work. Just the fingers are selling for around $8/pound on fleabay ready to process, not exactly a high profit idea, but could be good for making trinkets or accents.
If I actually do anything with this, I'll run a similar build thread to this one. What I hate about winter, it's too cold to work outside, so I sit inside and come up with ideas on how to destroy my free time in the warm months.
*** there was one Australian guy whose work looked promising until the end. He was doing a 1000 RAM card challenge, and using a soldering iron to strip the gold fingers and copper backings off the RAM. Went fast, no chemicals, looked great, until he tried to melt everything in a crucible with MAP gas. I wholly blame his failure on not knowing how to actually melt a bunch of metal. The 500 RAM chips worth of fingers he stripped off though weighed just over 3 Troy ounces, but that included the gold fingers, the copper backing, and I'm sure bits of silicon. Nothing a proper glowing crucible couldn't handle with some Borax, but not something a MAP torch had any business heating. Although at 2 - 4 sticks per computer, unless you work in a PC repair center, that just wouldn't be worth doing for most people. I'd say go check his videos out, but they turn into 45 minutes of him talking in circles without really saying anything.
With enough patience, one can even extract silver from old CDs. 21 cds made 0.1 grams though, not worth the time and hassle unless you have a truckload of them. 5600 cds per ounce of silver, you'd spend more on the chemicals than the silver would be worth and still be stuck with 5600 plastic discs.
