Interesting! I sold and am selling some type S thermocouples (Platinum/10%
Rhodium vs Platiunum) on Ebay, and in doing some research, found that one use of
this type of thermocouple is connected with the melting point of gold.
FWIW, there are gold stripping solutions available. I don't recall what they are
made of but probably some sort of cyanide concoction. The method *I* want to try
someday is to use mercury to disolve the gold, and then boil off the mercury
leaving the gold (I would guess as a powder.) And yes, I do know the dangers of
using this method.
Hi
You don't want to melt the other metals first, most
metals will dissolve the gold and just make it harder to
refine. The best method is with acid. Muradic acid
should work ok to remove the other metals.
Gold melts quite hot. I don't recall any heater wire
that wouldn't melt first. In an inert gas, as was mentioned
by another, tungsten could be used. Other methods
include things like carbon arc or oxi-acetylene.
Dwight