weeksie98
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Best way to prepare Ferric Oxide (Fe(III)2O3)
Hi, this is my first post, so sorry if I muck up!
Basically, I've been trawling through the Internet, looking for the best way to prepare ferric oxide for a thermite reaction. I have heard mixed
results for both oxidation in hypochlorite bleach/acetic acid and electrolysis in an NaCl solution. Can someone advise me which method has better/more
reliable results or a higher yield, and any common pitfalls with either one?
Thanks 
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bfesser
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Thread Moved
24-10-2013 at 14:05 |
Metacelsus
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Wet some fine steel wool with a solution of sodium chloride, and leave it exposed to air for a few days.
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AJKOER
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Dissolve Iron in Oxalic acid to form the insoluble yellow FeC2O4 (see Wikipedia http://en.wikipedia.org/wiki/Ferrous_oxalate ).
I would then heat in a flat disk (to reduce the action of exiting gases on the residue mixture) in nitrogen or, air with some O2 removed (but not from
burning in carbon compound as that adds CO and CO2).
The final product should be a fine Fe/FeO powder that will self ignite in air (see Youtube video at http://www.youtube.com/watch?v=XV4u4UooY8A ). Interestingly, allowing full mixing of the decomposition gases may form mostly Fe3O4/FeO. For a
reference, see Centre for Nanomaterial Research, Department of Physical Chemistry at Palacky University, link: https://docs.google.com/viewer?a=v&q=cache:ux-9_MSRuhEJ:... . To quote from the abstract:
"Using a device for thermogravimetric analysis, a dynamic study of thermally induced solid-state transformations of FeC2O4.2H2O in the atmosphere
allowing full participation of gaseous products (CO, CO2, H2O) in the reaction system was carried out. Solid phases formed at various temperatures
between 25 and 640 C were identified and characterized using 57Fe Mossbauer spectroscopy, TG and XRD. Up to 230 C, evolution of two molecules of the
water of crystallization takes place. Superparamagnetic nanoparticles of magnetite (Fe3O4) are formed as the primary product of the decomposition of
FeC2O4, together with gaseous CO and CO2. In the next stage above 380 C, the crystallization of magnetite is accompanied by a reduction of the
remaining ferrous oxalate to iron carbide (Fe3C) by carbon monoxide. Thermally induced conversion of iron carbide into a-Fe and carbon is expected
between 400 and 535 C as the major chemical process. In the last reaction step, above 535 C, magnetite is reduced to wustite (FeO) by carbon monoxide
evolved at lower temperatures. On the grounds of quantitative Mossbauer data possible competitive reactions are discussed and a temperature dependent
reaction model is suggested."
Also, the authors note:
"Depending on the experimental conditions, a diversified scale of reactions resulting in solid products varying in composition and valence state of
iron has been reported. From the point of view of the basic research, the mechanism of these solid-state reactions is the key experimental issue as
the published data are very controversial. The practical reason of interest in FeC2O4.2H2O is its easy thermal decomposability yielding various
nanocrystalline phases of iron including oxides with great application potential.[31–33] Obviously one can easily come across many experimental
conditions that influence transformation routes, their intermediates and the final products, but the reaction atmosphere represents the most important
one."
[Edited on 25-10-2013 by AJKOER]
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