Dan Vizine - 5-10-2014 at 11:05
I've been engaged in a small scale isolation of thorium metal. I'm at the stage where I'm doing final preparations for the first isolation of the
metal as a medium-sized metal powder with some fines. It will be potentially pyrophoric when first isolated (much as platinum is) but I expect to be
able to manage that by post-reaction treatments.
My question centers on what to do after that. I need to make this into thorium beads. Since Th is too reactive to melt in air, I assume thorium metal
is either melted in vacuo or under an inert gas or that it is formed into compacts that are vacuum sintered and then forged to full
density because Th is so soft (similar to copper). Surprisingly, I've found this information difficult to find by the usual routes.
I was wondering if any forum members may have knowledge about the nuts and bolts details of VAR with regard to these questions:
a) VAR seems to handle even things like Mo and W. Is VAR applicable to Th? I assumed it was, but am I missing anything?
b) Wiki says that samples are often vacuum induction melted first. Do they need to be? Can VAR samples be powders?
If not, I can make this powder into metal compacts using a hardened steel die set in my press (as I did with Pt in the past, prior to torch-melting).
Is this good enough to start the VAR process with?
Thanks.
Dan Vizine - 7-10-2014 at 18:58
Found a partial answer.....
Th can be melted by VAR on a water-cooled copper hearth in a vacuum or under inert gas.
And I'm guessing that the pressed compacts are good enough. It really only has to hold the metal still until melted.
Also found this:
[Edited on 8-10-2014 by Dan Vizine]
Attachment: Radiation Hazards Encountered in Arc Melting Thorium.pdf (1.4MB)
This file has been downloaded 426 times