Rust, Steel, Heat, and Magnetism We rusted some steel wool with
bleach and vinegar as catalyst. We removed the wool and drained
the liquid through a coffee filter. We tested the dried residue,
which was no longer magnetic. We then heated it in a spoon over
a candle flame, which turned it black. It was magnetic again.
What was the process that "remagnetized" it? Probably what you
did is drive off some of the oxygen from the rust (hematite or
goethite) turning it into magnetite, which is black and
magnetic. The balanced chemical reaction starting with goethite
would 12 FeO(OH) --> 4 Fe3O4 + 6 H2O + O2 That is the most
realistic, since rust is generally hydrated. The reaction is a
little easier to balance from hematite: 6 Fe2O3 --> 4 Fe3O4 + O2
Richard Barrans, Ph.D., M.Ed. Department of Physics and
Astronomy University of Wyoming Some oxides of iron are non-
magnetic, others are magnetic. Fe2O3 . nH2O (red rust) is
definitely non-magnetic. "Magnetite" mineral is an iron oxide
about like hematite, something like