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Ted Mooney, P.E. RET
Pine Beach, NJ
The authoritative public forum
for Metal Finishing since 1989
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The conversion of iron oxides--Fe3O4 to Fe2O3
Q. I am a post-graduate student doing research in converting iron oxide Fe3O4 (magnetite) into Fe2O3 (hematite). As we know, Fe3O4 can be considered as crystal 1:1 ratio of FeO (Fe+2) and Fe2O3 (Fe+3) and FeO can be oxidized into hematite at 600 °C. Can I fire Fe3O4 in air at 600 °C to obtain Fe2O3 ? This is because when oxidation is carried out, Fe3O4 will be converted into magnetite (Fe2O3) which is not stable and further stabilized as hematite at 600 °C.
Regards.
H Song Woonstudent - Kuala Lumpur, Selangor, Malaysia
2004
A. When you've done the experiment, you'll know the answer :-)
Bill Reynolds [deceased]
consultant metallurgist - Ballarat, Victoria, Australia
We sadly relate the news that Bill passed away on Jan. 29, 2010.
2004
A. As a post graduate student, you should be DOING THE EXPERIMENT, not asking people on the Internet for the answer. The purpose of post graduate qualifications is to expand our scientific knowledge, so if you get the answer off the Internet, the knowledge is already known and you don't deserve any PG qualification. Besides doing the experiment, look at the thermodynamics of the system and try to work it out from there, then see if the two answers agree.
Trevor Crichton
R&D practical scientist
Chesham, Bucks, UK
2004
Q. I'm a teacher I'm little bit confused whether Fe3O4 is electrically neutral or not and why?
Poonamteacher - ludhiana, India
2006
July 2014
Hi Poonam. I think the difficulty lies in the semantics. What exactly do you mean by "electrically" neutral?
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
Q. I am doing synthesis of Fe3O4 nanoparticles. If the nanoparticles come in contact with Oxygen will they oxidize to form Fe2O3? I am not sure about this ... please guide me.
Ajinkya NeneChubu University - Kasugai, Japan
July 9, 2014
July 31, 2014
A. Ajinkya,
First of all, Fe3O4 is already a mixture of FeO and Fe2O3. Might the FeO convert to Fe2O3? In the presence of moisture, possibly, but I don't know if the rate would be enough to worry about.
Ray Kremer
Stellar Solutions, Inc.
McHenry, Illinois
August 1, 2014
A. The relationship between the oxides of iron is deep water even for a corrosion chemist.
It is usually expressed in the form of Pourbaix diagram. For a fairly simple explanation take a look at...
http://corrosion-doctors.org/Corrosion-Thermodynamics/Potential-pH-diagram-iron.htm
Then find a chemist to explain it. You could write a fair sized text book on this one. Be very wary of simple explanations. Most practical chemists simply carry out the experiment under the actual conditions they are interested in.
Geoff Smith
Hampshire, England
Q. Moisture is okay ... but what about when they come in contact with oxygen??
What will happen?
chubu university - kasugai shi japan
August 1, 2014
Hi ajinkya. By "deep water", Geoff means "complicated subject". He has told you that he does not believe that you can reliably predict what will happen to iron oxide nanoparticles in the presence of oxygen in the general case. He appears to be implying that running an experiment for the specific case may be easier and more reliable than attempting to extrapolate from known cases. Best of luck.
Regards,
Ted Mooney, P.E.
Striving to live Aloha
finishing.com - Pine Beach, New Jersey
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