Dennis SK - 16-3-2012 at 04:00
Hello all.
Thallium
If left in air it oxidizes heavily.
I noticed that most companies deliver Tl in water.
Wont there form a heavy hydroxide layer that way?
Also, Whats the easiest way to remove the oxide layer without "eating away" to much of the metal?
Thanks in advance
neptunium - 16-3-2012 at 05:48
oxigen is the Thallium enemy. and as far as every sample of Tl i've seen it was always stored in a vacuum ampoule or inerte gas and often in oil.
never in water.
steam can effectivelly produce TlOH and moist air will destroy a sample rapidely.
the layer of oxidized (and TlOH) can be removed by simply cutting it away exposing the fresh metal underneath.
Thallium is very toxic and has killed before ,always wear gloves when handling it.
[Edited on 16-3-2012 by neptunium]
Zan Divine - 17-3-2012 at 15:36
I just had occasion to prepare a thallium sample for someone. The recommended crucible for Tl is cast iron and so a pipe cap with the interior threads
removed is a good choice. I milled a form into a graphite block, melted the Tl over a low flame outdoors (respirator) removed the dross by skimming
and poured the mini-ingot. The metal is a bright silver and stays that way under deoxygenated water.
Dennis SK - 18-3-2012 at 01:08
Ok Zan,
Sounds nice.
I've been thinking about making small "bars" of thallium or even melt it into ampoules.
Did anyone notice the very sharp increase in Tl price over the past few years?
I dont know what volume price is but from chemical suppliers like aldrich , alfa aesar stc. its about 6000 USD/kilo in 100-250g lots or more. (the
same stated on USGS)
Zan Divine - 18-3-2012 at 20:49
This was from GalliumSource, special order. $260/25g.