I could not find the thread, but, here is the post I copied and saved. I don't know how accurate this information is or if it is. So, I would do more research on it. Hope this helps you out some.
Ken
Here is some interesting info I ran across a couple years ago when I first started scraping computers for the PMs. I don’t remember where I got it but I think it might have come from the finishers discussion forum as that was one of the first places I found info about recovering PMs from electronics.
One ton (2000 lbs) of "average" circuit board from modern computers and electronics generally yields (in a very good system) between 8 and 11 troy ounces of 24k gold. This gold is found in a number of places, including the plated gold leads referred to earlier, on plated pins inside the connectors and on the board in a number of places and on and within the ic (integrated circuits) on the board itself. In addition, there will generally be around 10 to 20 times this amount in silver from the solder and other components (although depending upon the method of recovery, this yield may not be reached). Some types of electronic board have greater yields of silver and almost no gold; this is generally the board without connector ends and major ics. There are also minute amounts of palladium, platinum and other pgms (mostly in certain capacitors, but also in some chips and connectors). Your highest yields of gold in computer scrap especially are rarely from clipped plated leads, but from the processor/cpu, memory and other ics (which can yield 2 gm/lb or more, depending upon the type and age). Many of the older electronics and early computer equipment will be much much higher in volume, while the newest (97 and newer) I would surmise would be lower, although I have not processed enough to tell you for sure. There are, of course, many other places (like automotive catalytic converters) where you can find precious metals that may be recycled, but the scope of this section seems to be on electronic board/PCB so I will stay on that subject.
So (if the above is true) the average recovery of 1 ton PCBs would be 9.5 OzT Au & 142.5 OzT Ag
At todays market price 9.5 oz Au X 1585.70 = 15,064.15 per ton PCBs & 142.5 oz Ag X 28.38 = 4,044.15 per ton PCBs.
A computer has “on average” 2 lb CB in it (this is ALL boards – mother boards, RAM, Cards & HD/CD/DVD boards) so that is about $15.06 Au & $4.04 Ag per computer
On “average” you also get about $4 in copper aluminum & tin out of a computer (this does not factor in the copper in the CBs – only the copper from the wire)
This makes the average scrape value of a computer about $23. --- that is without factoring in the PGMs &/or copper in the CBs. It would be cool if someone could come up with those numbers as well.
