# Molybdenum



## jarlowski1 (Nov 20, 2016)

I need some advice on how to start recovering gold from this chunk of molybdenum. The guy I got this from owns a gold coin shop. I have no idea where this Mo came from. The guy told me that he had taken it to a friend that tried to melt it. I don't know what kind of flux this guy used so I figured I would ask how someone with experience working with Mo how they would go about processing this mess for recovering the gold. I don't want to recover the Mo. My initial thoughts were to digest it in dilute Nitric but I figured I would ask before anything further was done. Here are some pictures of it.


----------



## goldsilverpro (Nov 20, 2016)

The melting point of molybdenum is 4753F, way too high for a gas furnace. With something that hot you not only need a furnace that will get that hot, you need a crucible that will take that much heat without melting. As a reference point, gold melts at 1948F and common carbon steel melts at 2750F.

Was the gold on the surface or is it alloyed with the moly? If alloyed, how do you know this?


----------



## jarlowski1 (Nov 20, 2016)

Thats a good question. I tried to get as much information from the guy as I could but he is a man of little words. He did say that he had more that he took to a different person and they were able to get a sizable amount of gold from what he gave them in the amount he gave me I estimate that there is around 2 grams from the numbers that he told me. So i know there is gold there. I cant see gold on the surface but as you can see the whole piece is severely discolored from the guy trying to melt it. I''ve tried scratching some with a razor but it is so hard the blade won't even make a mark. So my best guess is that it is an alloy.


----------



## g_axelsson (Nov 21, 2016)

It is hard to see from a flat picture, but it looks to me that every piece is too straight to be a piece of metal that's been in a furnace. Is it all fused together in a clump or individual pieces? Can you bend one plate or will it break?

Göran


----------



## jarlowski1 (Nov 21, 2016)

It has a slight curve to it like the guy had it in a ladle. It is all fused together it wont bend if i try to break a piece off it snaps off.


----------



## Lou (Nov 21, 2016)

Yeah, they won't be able to melt it.

Probably evaporation boats from gold physical vapor deposition.

We do those and the tungsten pigtails all the time and I'd be happy to look at a sample for your friend. 

The other issue is that these could be pieces of TZM (tungsten-zirc-moly) which will XRF like gold but not have any gold. Did you see the physical gold or he just said it analy;zes for gold?


----------



## g_axelsson (Nov 21, 2016)

Hmmm, I suspected it would just snap. To me it looks more like silicon dies than some molybdenum alloy. If it is silicon then it would look like a shiny black glass where it breaks. A metal would be more dull and not shiny.

Anyhow, if it breaks then it would be possible to crush a sample to a fine powder and leach with aqua regia. The liquid could be tested with stannous chloride afterwards to check for gold in solution.

By the looks of it I wouldn't suspect any gold at all, but you never know unless you test it.

I don't think it is Mo-boats from an evaporator, the Mo sheets wouldn't be in the form of squares and it wouldn't just snap if you try to bend it. I got an evaporator and a sheet of Mo-metal that came with it but I haven't used it yet, it just stands in the back of the workshop.
This is how boats looks. https://www.plansee.com/en/products/components/components-for-coating-systems/evaporation-boats.html

Good luck and let us know how it works out.

Göran


----------



## jarlowski1 (Nov 21, 2016)

Lou i did not see the physical gold from what he had processed but like i said he owns a gold shop so I really dont have reason to suspect that he was mistaken on the stuff that he had done already. Although you never know. As for processing it in AR i thought that i read somewhere on here if you did that the Mo would create a trioxide that would be a mess assuming it is an alloy i could be wrong as i read that months ago. What are your thoughts on that.


----------



## Lou (Nov 21, 2016)

I just burn them in the tube furnace (the oxide is volatile) with excess pure oxygen. Then give it all a good rinse with dilute sodium hydroxide, filter and melt. 

THe big thing is having a way to contain the Mo.


----------



## jarlowski1 (Nov 21, 2016)

Thanks for your help I'll see what I can come up with.


----------



## brijes (Nov 21, 2016)

Hello all, I used to work manufacturing molybdenum and as far as i knew no gold was used.
They fired the stuff using the same stuff that makes firecracker wicks.

Sent from my SM-G903W using Tapatalk


----------



## g_axelsson (Feb 14, 2017)

Any news on the recovery?

Göran


----------



## jarlowski1 (Mar 3, 2017)

I haven't attempted the recovery yet. Im going to do the AR leach when the temp outside warms up. Ill let you know how it turns out. Thanks for checking back with me.


----------

