William Wixon wrote:
the scrap yard employee brought out a hand held electronic device (would be
like a LARGE cordless drill) and said something about "...it burns it.."
and held it up to the chunk of aluminum, apparently the device "burned" the
aluminum and read what constituents were in the smoke. then he held it so
the camera could see the read-out and it listed two possible aluminum alloys
(both were in the "70XX" family). i was amazed. never heard from you guys
there was such a thing, and, was amazed it gave a read-out of the alloy
number, woulda assumed it would tell, in percentages, what metals were
present and the operator would have to discern what alloy it was. looked
like it was an expensive machine. hard to believe a scrap yard would have
one! i don't think they said, but i assumed it could also read alloys of
steel etc.

Arc emission spectrometer. Commonly used in big scrap-yards.
One such product is "Arc-Met". The idea is to have electrical
arc between device and item, and see what wavelengths of
light there is in the arc emission.

The other kind is x-ray fluorescence (XRF) spectrometer.
They use a radioactive isotope in the device, irradiate the
item with x-rays from isotope and analyze the x-ray
spectrum from the item to be analyzer (fluorescent x-rays).
One such device is "X-Met". One needs to change the isotope
(109Cd, 55Fe, 57Co, 153Gd etc.) based on material group.

One famous manufacturer of there is Finnish company
Outokumpu, who developed these Arc-Met and X-Met products.
Of course, the point is that these are small enough to
be easily portable. These can tell carbon content of steel
very accurately too. Works with steel, stainless steels,
aluminum etc..

Kristian Ukkonen.