axehandle - 4-3-2004 at 11:21
I'm not a beginner, but here goes:
What would sulfur trioxide do to a fused
mixture of ammonium phosphate,
magnesium oxide, quarz and crystobalite?
My guess is: nothing. But I want to be sure. I can't find any resistance information w.r.t. SO3 on any of the compounds.
I'm asking because those are the main ingrediants in dental casting mold cement, and I intend to line my catalyst tube on the inside with it (to
protect an integral NiCr heating spiral).
chemoleo - 4-3-2004 at 11:32
If the sulphurtrioxide is free of water, I should think that nothing would happen. Best thing is to try - Just put a chunk of your salts into a
container and fill that with SO3 (you can get SO3 by heating Na2S2O8 (or 7 even?) by melting it.
axehandle - 4-3-2004 at 11:45
Thanks chemeleo. I was going to use the method of "try and perhaps die" anyway, since I've got more than enough raw materials to build
another catalyst chamber should the first one fail. IMHO, I suspect slow erosion, since atmospheric H2O will form sulfuric acid with the SO3 in the
chamber.
There is one advantage though: The temperature in the chamber will be 450C, well above the boiling point of H2SO4, so there won't be any H2SO4
floating around in the tube --- it's the gaseous miniscule amount of H2SO4 I'm really worried about.
An idea just struck me: I'll simply pass the ingoing (to the sulfur burner) airstream trough a filter filled with CaCl2. That should kill any
pesky H2O molecules.
Science strikes again!
t_Pyro - 8-3-2004 at 02:16
My guess would be that magnesium sulfate would be formed. The others won't react for sure. Magnesium oxide is a basic oxide (just below Calcium
in the electropositivity series), and hence will react with sulfur trioxide, an acidic oxide.
axehandle - 8-3-2004 at 05:38
Perhaps I'd be better off using gypsum then. It's already thoroughly sulfated, considering it consists of calcium sulfate....
/A