texaspete
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separation of iron from iron oxide
I recently acquired a five pound mixture of iron oxide and iron particles. It came from the floor of some sort of machine shop, so its pretty messy. I
plan to make a heaping load of thermite with it, but that is not possible as it is now.
So far, I've run it all through a sieve to get the large particles out, and now I'm left with a mixture of rust and iron particles. Now, I either have
to separate the iron or convert it to iron oxide. I tried to separate them with a magnet, but had no success. If HCl is added, it will dissolve the
iron oxide more quickly than the iron, making iron chloride.
Any suggestions are welcome.
PS- I have a fair amount of oxidizing agents-(KMnO4, KNO3, Ca(ClO)2, NaClO, 27% H2O2), the standard acids, most OTC organic solvents, and NaCO3 and
NaOH for bases.
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chief
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You could oxidize the rest of it electrolytically, by using the powder at the ground of some NaCl-bath as anode ; or maybe wet it with saltwater and
let it aside 4 weeks ...
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kilowatt
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What oxidation state is the iron oxide? You could separate out Fe2O3 from iron by magnets could you not?
The mind cannot decide the truth; it can only find the truth.
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kclo4
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Does HCl react with Iron oxides? Some glass stained from an Iron compound that looks rusty doesn't get clean with HCl - also I thought they used
phosphoric acid for this reason to dissolve iron oxide instead of HCl.
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Mr. Wizard
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If what you have is black slag and sweepings from the floor of a welding shop, just sift it through a piece of aluminum window screen attached to a
wide mouth jar. The stuff that doesn't fall through can be put in a pile and recycled after it's pounded in a mortar and pestle fabricated out of any
steel pipe or similar material. Most chunks of steel won't break up enough to fall through the screen. That's low tech, and it works.
Plan B, which I haven't tried, would be to heat the iron oxide, iron mix, in a terra cotta flower pot surrounded by a charcoal fire until it was red
hot. Then introduce air or oxygen into the opening at the bottom of the pot. You have to do this slowly, as it could cool the iron instead of
oxidizing it. It could also cause it to become too warm and melt and run out. If you use O2 you might even end up with red iron oxide.
After pounding try sifting the material through fine screens.
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texaspete
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| Quote: | Originally posted by chief
You could oxidize the rest of it electrolytically, by using the powder at the ground of some NaCl-bath as anode ; or maybe wet it with saltwater and
let it aside 4 weeks ... |
How would I use powder as an anode? Just stick a graphite rod into it? Also, I'd rather not use an NaCl bath due to the chlorine gas that it creates.
| Quote: | Originally posted by kilowatt
What oxidation state is the iron oxide? You could separate out Fe2O3 from iron by magnets could you not? |
I thought it was Fe2O3, but apparently it is a mixture of various oxides, because both the iron oxide and the iron stuck to a magnet.
| Quote: | Originally posted by kclo4
Does HCl react with Iron oxides? Some glass stained from an Iron compound that looks rusty doesn't get clean with HCl - also I thought they used
phosphoric acid for this reason to dissolve iron oxide instead of HCl. |
Good point. I'll go check on the solution with HCl. However, it sure looked like it was dissolving.
Mr Wizard-
I already put it through a kitchen sieve, which should be at least equivalent to screen.
Plan B sounds interesting, I may have to try it on a small scale. If I heat up iron oxide too much, doesn't it reduce to Fe(0)?
Thanks for the suggestions all!
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Mr. Wizard
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No you won't get FeO unless you add a reducing agent of some sort. Keep the flower pot edge higher than the charcoal so you have an oxidizing
atmosphere in the pot. Add a small amount of fresh air into the hole at the bottom. What you'll get in air should be Fe3O4 a black oxide. With an
enriched O2 atmosphere, and I'm not sure here, is more of the red Fe2O3, which has a better oxygen balance. The black will work just fine for your
purpose, and heating it up will drive off all the oil, and organics that get mixed in. Is the stuff welding slag? If it's from heavy grinding, it
may contain a lot of grinding wheel components and other useless stuff. I got a 5 gallon bucket load after sweeping up a welding shop and it works
great as an iron additive for my garden 
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chief
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How to use the powder as anode: Let the bottom of the electrolytic cell be of an iron-plate, if you have no inert material. There upon the filings are
placed .
Electrolyzing with this as the anode will
==> at first mostly consume the filings,
==> and after a while the plate too ... ;
But I would just let salt-water corrode it in the presence of air ... ; takes only weeks in case of normal steel-filings.
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