Brown AR

[ThePierCer]

I've had a bunch of PI, PII and AMD processors soaking in AR in a shelf for about 2 weeks now. When I checked it, the solution was deep brown. All the gold appears to be off the chips.
Whenever I've used AR, it was always deep green. Is this normal? I'm guessing there is something else disolved in there too.

 

[goldsilverpro]

Sounds like iron. Kovar is 54% iron.

 

[lazersteve]

Did you put any Pentium MMX or Celeron Black Fiber Cpus in the mix? If so the pins are most definitely gold over kovar. Also most all newer socketed cpu's pins past PIII class. Chris is right, kovar is mostly iron which produces a red brown color in solutions containing chlorine. According to wiki kovars composition is 29% nickel, 17% cobalt, .2% silicon, .3% manganese, and 53.5% iron (by weight).

Steve

 

[bermudanibiru999]

So is the AR still salvageable or what?

 

[lazersteve]

If any gold went into solution it should drop as normal, but may require some extra rinsing in the funnel. Dilute HCl does a good job of purging ferric chloride residues from filtered gold.

Steve

 

[goldsilverpro]

Was there any organic material on the parts, such as resins? This might also create a brown AR soln. Organic material will almost always turn strong sulfuric black or brown.