How to process gold leaf rolls?

[Hartbar]

Good morning, came accross a bunch of these gold leaf rolls. Appear to be high karat gold, but very thin and fragile.
Wondering how to process?
Thinking maybe straight into AR, paper turns to pulp, then filter?
Or, is light incineration better way to burn paper off?
Thanks in advance for any input.

 

[Yggdrasil]

Good morning, came accross a bunch of these gold leaf rolls. Appear to be high karat gold, but very thin and fragile.
Wondering how to process?
Thinking maybe straight into AR, paper turns to pulp, then filter?
Or, is light incineration better way to burn paper off?
Thanks in advance for any input.

I'm afraid there's less Gold than you may think.
Best is if you find parts that are reasonably whole, then it may be sold at more than Gold value.

 

[eaglekeeper]

is light incineration better way to burn paper off?

I've have never done this type of material, so I'm not for sure. I would be concerned that if you incinerate, some of the foils would be carried out with the air currents.

Is the paper backing wax coated?

 

[anachronism]

It's fine enough to dissolve in HCl/bleach. I'd cut the reels and put the lot in because if the liquid can get to the gold it'll dissolve it. Alternatively if you're good with AR I'd do the same with AR.

 

[Hartbar]

Not sure on yield because I’m not sure on length of rolls.
I took a 12 inch section of roll and removed the foil from paper. Got 20 milligrams of gold material that test 98% pure, that’s about $1.65 per foot?
I don’t think the paper is wax paper.

 

[4metals]

I have processed this material many times, I just used hot aqua regia and the paper turned to pulp and all of the gold dissolved. Usually the packages were marked with the gold content and purity. I have seen 14K gold leaf as well.

 

[Alondro]

Yeah, material that thin is likely best done chemically. As another has said, you can even use HCl-bleach to dissolve such thin gold, which is the cheapest chemical method. But you will have to wash the paper A LOT!! At least 3 hot water boils to get the bulk of the gold chloride solution out of the mass of paper.

 

[4metals]

I remember once a customer came in wanting to have us process his gold foils in front of him. (Not unusual in NYC, where nobody trusts the refiner.) He brought in quite a few rolls as he was retiring and wanted the cash. I was hesitant to melt them because I have seen paper emerge from a melt where the gold melted and unburnt filter paper remained in the crucible (lack of oxygen). To avoid this we just cut off strips, as long as the crucible was deep, and tossed them in one or two at a time. The paper burned off nicely and the melt, with a small scoop of borax added at the end, poured into a nice bar. That was before XRF so we took a small sample, digested it in aqua regia and ran it on the Atomic Absorption. I remember it was high nineties purity.

 

[snoman701]

I like that...the paper turning to pulp. When I did it, I put the roll in a porcelain crucible and pyrolyzed it, then oxidized the ash, then used AR.

 

[Alondro]

I like that...the paper turning to pulp. When I did it, I put the roll in a porcelain crucible and pyrolyzed it, then oxidized the ash, then used AR.

It's certainly possible to burn the paper off, IF you can be sure there won't be too much of a draft to suck the foils away. I would suspect an electric furnace would be very good for this purpose.

 

[anachronism]

It's certainly possible to burn the paper off, IF you can be sure there won't be too much of a draft to suck the foils away. I would suspect an electric furnace would be very good for this purpose.

Hehe I avoid flames or furnaces or pyrolysis as much as humanly possible. Chimneys and "up the" figure too much.

 

[goldshark]

Usually a slight breeze is enough to separate the foil from the backing. Blow it through a colander, to catch the leaf. A hair dryer on low should be sufficient.

 

[Alondro]

Hehe I avoid flames or furnaces or pyrolysis as much as humanly possible. Chimneys and "up the" figure too much.

I have a brick outdoor furnace, and I use a 4-foot tall piece of cast iron pipe about 6 inches in diameter for pyrolysis, with the bottom sitting in a cast iron frying pan so nothing gets lost. It's so tall, nothing can draft up out of it, and all organic material carbonizes completely since I can get the furnace easily up to near 2000F just tossing wood into it with no blower at all.

Got a lot of hard oak firewood, and it burns very hot.

I suspect with a blower, I could conceivably hit temps so high the bricks would crumble and the cast iron would melt! But for those temps, that's why I bought Kaowool for an insert. Doesn't need baling wire, since it rests inside the brick walls snugly.

And since I never know when to quit when building things, I also got parts I can use to convert it into a pizza and bread oven by setting a steel plate on top, moving a few bricks to make vent holes, and then building a loose oven structure on top of the steel plate that only takes 5 minutes to put together.

You can do lots of stuff with loose-brick structures when you think about it!