Sciencemadness Discussion Board

Thermite driven furnace

dann2 - 7-2-2007 at 18:51

Hello,

Would it be possible to make a one-off furnace driven by Thermite. I have not seen anyone on the web actually do this so there must be some obvious reason why it is not feasable. Perhaps the temp. is simply too high for any materials to hold in the Thermite?

I want to melt Magnetite. It seems this would be a simple way to get the required temperatute (and beyond) as thermite is capable of 5500 Degrees F. I have a graphite/clay crucable. It would seem that you would need some sort of modifier with the Thermite to keep the temperature from going up to the max. possible. If you were to use an excess of Iron oxide would this keep the max. temp. at a more managable (and useful) level.

What to build the actual furnace bottom out of? Would graphite do.

Cheers,

Dann2

[Edited on 8-2-2007 by dann2]

Fleaker - 7-2-2007 at 18:59

No there are materials that will hold the thermite in, but they're rather exotic and hard to deal with. Keep in mind that it produces a lot of very very hot liquid iron, not iron oxide. Curiously, you can use magnetite to make thermite.

Graphite would do. On Theodore Gray's website he does this: http://theodoregray.com/PeriodicTable/Samples/026.17/index.v...

in a graphite mold.

I just answered a question about melting magnetite not too long ago, was it you who asked this question? Refer to that post. It is not hard to melt.

12AX7 - 7-2-2007 at 19:00

Lots of heat, none of the heat transfer, none of the heat capacity (all that temperature goes into melting and fusing itself, eh?), and none of the cleanup. Or tempering you need for magnetite, for that matter.

Tim

dann2 - 7-2-2007 at 19:39

Quote:
Originally posted by Fleaker
No there are materials that will hold the thermite in, but they're rather exotic and hard to deal with. Keep in mind that it produces a lot of very very hot liquid iron, not iron oxide. Curiously, you can use magnetite to make thermite.

Graphite would do. On Theodore Gray's website he does this: http://theodoregray.com/PeriodicTable/Samples/026.17/index.v...

in a graphite mold.

I just answered a question about melting magnetite not too long ago, was it you who asked this question? Refer to that post. It is not hard to melt.


It was indeed myself who asked the question. You stated that a propane driven furnace would melt magnetite. What temperature will a Propane furnace go up to? Magnetite melts at 1595C.

On the link from your post the Author stated that Thermite is the only feasable way for to home cast Steel?

"Making the iron link was definitely the most exciting, because I did it with thermite, the only practical home method of making molten iron. (Iron is basically impossible to melt and cast without very special equipment, but see some of the other samples above for a description of the thermite process, which creates molten iron on demand.) "

I have heard of people casting Iron with home furnacews. Perhaps it is cast Iron as opposed to steel.

Thanks for prompt reply.

Dann2

chemoleo - 7-2-2007 at 19:42

Also, forgive my lack of substance on this particular issue, the Romans were able to cast iron, make swords and so on without the requirement of 'very special equipment'.
They could do it with carbon/coal, and clay, so why shouldn't we be able to?

The_Davster - 7-2-2007 at 20:58

Quote:
Originally posted by chemoleo
They could do it with carbon/coal, and clay, so why shouldn't we be able to?


Got enough slaves for the bellows?:P
That said, how did they do it? Just charcoal and a lot of air? I have been meaning to take a course on blacksmithing, havent got around to it yet.

[Edited on 8-2-2007 by The_Davster]

12AX7 - 7-2-2007 at 23:46

Bloomery process, as I recall. Load reasonable ore and charcoal into a mound, light it and blow a hell of a lot of air into it, hoping that your air pipes don't melt in the process (they can be water cooled in some cases). I don't know that they cast any iron, but they forged plenty. Once you have the bloom, you need only be an experienced blacksmith to work the glob, which consists variously of rust to mild steel to cast iron, into useful billets of carbon steel or wrought iron (which is mild steel with slag inclusions).

Speaking of the ancients, I think it's amazing that they had essentially everything we descendents of Europeans had to start the industrial revolution, except one thing: the blast furnace, and possibly coal to fire it. (Coal isn't necessary, but it sure helps, being more plentiful than trees, which are also useful for building your warships, among other things.) If they had discovered and developed the large scale iron casting, refining and steelmaking process, we'd probably be two thousand years ahead!

Tim

not_important - 8-2-2007 at 00:18

Wind furnaces, or dragon furnaces. Build a furnace so that the natural winds take the place of bellows, in most cases the draft helps as well.

One write-up is here
http://www.nature.com/nature/journal/v379/n6560/abs/379060a0...
but I know I've seen descriptions of similar devices in other parts of the world. They're also used for firing pottery.

I've seen a wood fueled wind furnace overshoot cone 12, around 1320 C, which is about hot enough to melt some grades of steel.