Does anyone think it would be possible (hypothetically, if you could find a suitable container) to make a thermite using cerium, lanthanum, or
praseodymium to reduce tungsten(IV) oxide in order to release molten tungsten? Those rare earth metals seem to be the only highly reactive metals
with a suitably high boiling point.Bert - 27-11-2007 at 21:01
I believe you will find Titanium sufficient, and easier to come by as well. Graphite might just barely serve as your container...
I also believe this belongs in the above sticky thread on exotic thermites, not in a new thread.
[Edited on by Bert]Sauron - 28-11-2007 at 02:38
There's a document kicking around the forum on exotic thermites. I have posted it previously. Worth your while to look for it. UTFSE.franklyn - 28-11-2007 at 03:44
WO2 + Zr -> W + ZrO2 __ -1100 - ( -590 ) = - 510 KJ per mol of W
WO2 + Th -> W + ThO2 __ -1226 - ( -590 ) = - 636 KJ per mol of W
Given the very high heat of fusion of Tungsten , WO3 gives higher results
2 WO3 + 3 Zr -> 2 W + 3 ZrO2 __ 3( -1100 ) - 2( -943 ) = - 707 KJ per mol of W
2 WO3 + 3 Th -> 2 W + 3 ThO2 __ 3( -1226 ) - 2( -943 ) = - 896 KJ per mol of W
WO3 and Thorium looks like a winner
________________________________
For comparison the thermite reaction of Iron oxide and Aluminum
Iron ( Fe2O3 ) -824 _ KJ / mol
Aluminum ( Al2O3 ) -1676 _ KJ / mol
Fe2O3 + 2 Al -> 2 Fe + Al2O3 __ -1676 - ( - 824 ) = - 426 KJ per mol of Fe
.kilowatt - 28-11-2007 at 15:13
Wouldn't WO3 be too volatile?
Also is there a way this discussion may be moved to the exotic thermites thread?
[Edited on 28-11-2007 by kilowatt]franklyn - 22-12-2007 at 22:16
Quote:
Originally posted by kilowatt
Wouldn't WO3 be too volatile?
An oddity of high melting temperature metals is that their oxides will boil at
much lower temperatures , it is a physical property and unavoidable. The
oxides of Tungsten are such. How the mixture is preheated and initiated will
determine the vigor of the reaction and mitigate gas formation. It may be
desirable to initiate from the bottom up instead of top down , this way
the heat is retained by the tungsten which sinks and the Thorium refractory
oxide as it forms protects the mixture above from excessive heating. Quite
the opposite from what occurs if started from the top. Another approach
might be to press the mixture at very high pressure into a solid which then
would be heated to initiation by high frequency magnetic induction.
theres a thread on induction heating here _ http://www.sciencemadness.org/talk/viewthread.php?tid=3626
another note here describing induction preheating of Calcium thermite _ http://img31.imagevenue.com/img.php?image=82480_P_u_31lo.jpg
also posted in the Thermite thread _ http://pyrobin.com/files/thermit(e)%20journal.pdf
This attachment is selections from _ Handbook of Preparative Inorganic Chemistry Vol 2 , George Brauer
