optical scrap gold frame

[Anonymous]

Any one know what metals are in optical frames marked 1/10 12 kgf

 

[lazersteve]

Steel.

Steve

 

[goldenchild]

Sometimes aluminum. Those stink because you obviously cant process with nitric right away.

 

[Harold_V]

Steel.

Steve

Don't think so. They tend to be copper/nickel alloys. There are exceptions, including some made of titanium, plus some have aluminum decorative items attached.

It's very hard to generalize where eyeglass frames are concerned. Having processed them by the thousands, I believe it's safe to say that I encountered pretty much every base element you can imagine, including steel. It would have been limited in application because of its potential to rust.

Do keep in mind, I'm discussing eyeglass frames of more than 20 years ago. Don't have a clue what they use now.

Harold

 

[lazersteve]

Steel.

Steve

Don't think so. They tend to be copper/nickel alloys. There are exceptions, including some made of titanium, plus some have aluminum decorative items attached.

It's very hard to generalize where eyeglass frames are concerned. Having processed them by the thousands, I believe it's safe to say that I encountered pretty much every base element you can imagine, including steel. It would have been limited in application because of its potential to rust.

Do keep in mind, I'm discussing eyeglass frames of more than 20 years ago. Don't have a clue what they use now.

Harold

I've only processed a limited supply of them (around 2 kg of frames) and most of the ones I encountered were an alloy of iron. I was having trouble using nitric to dissolve the frame from under the gold and decided to try a test sample with hot melt dry version of AR (ammonium chloride and ammonium nitrate), a recipe I found in an assay book. The result was gold flakes and a liquid which turned to rust when dehydrated.

I have also seen some other metals but the bulk of the ones I processed (all from the same source) were an alloy of iron.

I should have considered that the ones I processed were not necessarily the norm.

Here's a snapshot of the dry AR test results on a bridge from the eyeglass lot:

You can see a metal strip from inside of a nose pad had a little copper in the photo also (blue green) but the bulk of the metal present from the bridge was iron (red brown). There is also gold present mixed in with the iron.

Steve

 

[Platdigger]

There is a patent that talks about using this dry AR mix on ores and such.
Could also use sodium or potasium chloride with sodium, potasium or ammonium nitrate.

 

[goldsilverpro]

One time, about 25 years ago, we melted about 12 drums of them - maybe 1000-1500#. They were just the GF metal frames. All of the plastic and glass, etc., had been removed by the local Lions Club in Portland, OR, who had collected them through their eyeglass program and then sorted out the GF ones for refining. I'm thinking that we recovered the gold by dissolving the base metal in nitric, but we might have just assayed and shipped the bars. I do remember that the base metal ended up being primarily a copper alloy with some Ni in it. There was also some Fe and Al in it but it didn't amount to that much of the total.

 

[Harold_V]

I'm thinking that we recovered the gold by dissolving the base metal in nitric,

That was my normal procedure. Glass and aluminum was removed, then the frames were incinerated. By heating to redness, they came apart completely (silver soldered together). I then used dilute nitric. It was obvious there were various elements present---at first the copper based material readily dissolved, all without issues. As the copper allow was eliminated, the remaining material was much harder to digest (not having been melted, it was well protected by the gold covering, which didn't help). Prolonged heating eventually resulted in complete elimination of the base metals. I then got all the remaining solids back in a filter, to eliminate all traces of solution. The residue was then incinerated, then screened, at which time I could remove the screws (which did not dissolve in nitric). A boil in HCl afterwards, a rinse with tap water, then on to AR. The HCl wash was very important---insuring that the gold chloride solution would filter easily.

The era of eyeglass frames good for refining was coming to an end long before I closed the doors on my refinery. It was getting harder and harder to find the old type, plus the newer styles were lower in gold content, and made from different materials. I'm convinced that is what Steve has experienced. He's no fool and knows exactly what he's doing---so his report is every bit as valid as yours and mine.

By the way, once the copper alloy was eliminated, a 4,000 ml beaker with but a couple hundred ml of solution, along with the remaining frames, would easily boil over once the solution achieved critical temperature. Very little activity, then an almost instant foam-over. It could be stopped by adding considerable cold water, but I cleaned up one hell of a lot of spills from processing eyeglass frames. No harm done---everything wiped up (paper towels), incinerated, and re-processed. The gold, at this point, was in tiny particles, not solution.

Harold