UnintentionalChaos
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Stainless steel
Well first of all, I now have some stainless steel scrap. A 3 dollar bowl from Wal-mart...I guess you get what you pay for. I was drying up some MnO2
in it (which to my best knowlege won't react with the steel at all, but there were some particles of something in it that did.) I have nice little
patches of holes eaten through the bottom of the bowl 
Anyway, I know some members have done nickel extractions from cutlery, so I was wondering if it is possible to do the same with the chromium in
stainless steel. The only potential alloy designation that the bowl has is 80202/523. 80202 gave me squat in terms of search results, but 523 would
mean a heat resistant chromium alloy of some kind. I, however, doubt this and assume it is probably either type 304 (18% Cr and 10% Ni) or
food/surgical stainless type 316 (17% Cr 12%Ni 2%Mo). What could I do, preferably chemically or with electrolysis, to seperate the constituent metals?
I'll continue to look into it myself, but your thoughts would be most appreciated. I don't even really care if metals are even possible. Salts would
be just fine. 
[Edited on 12-28-06 by UnintentionalChaos]
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Maya
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I would dissolve it in some acid , sulfuric or hydrochloric first then separate the salts
\"Prefiero ser yo extranjero en otras patrias, a serlo en la mia\"
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kaviaari
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Are you sure that the manganese dioxide that you used was pure? I am not sure if impurities can do that kind of stuff. Very odd indeed.
You could dissolve the bowl or whatever is left from it to acid and then by controlling the pH precipitate certain compounds. Just like they do to
leftover chemicals containing metals.
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12AX7
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I've tried it myself, I have some mixed chlorides laying around somewhere. The deep green solution does not appear prone to drying out, even in the
winter air!
Iron seems to crystallize out, though, and I think I have some iron and nickel chloride or sulfate (I forget which), mostly seperated from chromium,
that's progressively getting darker, I think suggesting it is going from the paler iron to a deeper nickel-rich crystal. Fe(II) and Ni(II) form a
solid solution most of the time, right?
Tim
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hinz
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I have done this by electrolysis in diluted sulfuric acid. But my alloy contained mostly copper and nickel, so I just had to electrolyse it, at the
anode all the alloy got oxidised and dissolved as sulfate. At the cathode the Cu(SO4)2 got reduced to copper, wereas the nickel wasn't reduced due
it's lower potential (-0.25V).
Maybe you can try the same and break your bowl in two pieces, one as anode, the other as cathode.
now you electrolyse it, I expect the iron will be oxidised to fe3+, the sulfate is unstable, so it will precipitate as Fe2O3. This will make this
electrolysis a bit messy, but with some buchner funnels and a centrifuge, you should get rid of it.
When you have filtered most of your Fe out of it, I would treat the solution with H2O2 to oxidise the rest of the Fe2+ to Fe3+ to get it out as oxide.
The chromium might also precipitate as Cr(IV) oxide.
Now you can try to get the nickel and the molybdenum out of it, maybe with H2S as insoluble sulfite.
There are certainly some other methods, so some other members probably have better experience with it. Especially chromium and molybdenum will be hard
to separate.
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guy
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Is this MnO2 from a battery? If it is, then ammonium chloride might have eaten through it.
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UnintentionalChaos
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It was from a battery...I came to that conclusion about the chloride earlier today. I had washed it 5 times, but perhaps some lumps persisted. The
bowl had almost 6 months of use behind it, so for 3 dollars (and given how poorly made it was...the bottom was quite thin), it served its usefulness.
My real labware comes in in a week, so I'm not real broken up about it
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