The Volatile Chemist
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Manganese Dioxide
What are some easy ways to get manganese chemicals from manganese dioxide? I tried an Iron Manganese dioxide thermite w/o success. Are there any
(easy) ways to get manganese compounds?
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elementcollector1
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"Iron Manganese dioxide thermite"? What is that?
Search "Manganese Chloride Crystals" on this very sub-board...
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sasan
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Volatile chemist,I have a topic about MnO2 reactions in the {beginings page 5}
Maybe it can answere your questions
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blogfast25
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In essence all treatments of MnO2 come down to reducing it to Mn(II) using various reducing agents like HCl (gives MnCl2), SO2 (MnSO4), oxalic acid
with H2SO4 (MnSO4), H2O2 and acid (Mn(II) salt) and others. This topic has been chewed into very small pieces on SM, so use 'search' to find
everything you need (including MnO2 thermite).
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Bert
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As far as the Manganese dioxide thermite:
Al/MnO2 thermite releases the Mn as a GAS. Which burns in air very well. Much like refining Zinc, the product is a gas at the temperature
it comes off the reaction, so you've either got to condense it without exposure to atmospheric O2 or run the gas into another reaction or
alloying operation you want the product of.
The mixture has been used as a solid rocket fuel, the appearance when fired in dayligh is kind of neat. A dark smoke trail following the bright flare
at the exhaust nozzle from the burning Mn vapor... Called ALMAD rocket fuel by the guy who developed these, there was an article in the Pyrotechnics
Guild Bulletin a while back.
[Edited on 6-4-2014 by Bert]
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blogfast25
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Quote: Originally posted by Bert  | As far as the Manganese dioxide thermite:
Al/MnO2 thermite releases the Mn as a GAS. Which burns in air very well.
[Edited on 6-4-2014 by Bert] |
These are both half truths. Me and another experimenter here have obtained Mn lump metal from aluminothermic reductions of MnO2 with Al powder,
although yields are poor (30 to 50 %).
It's true that that particular thermite suffers from an affliction: the boiling point of manganese is very close to the melting point of alumina and
so considerable part of the manganese metal effectively evaporates during reaction. I have found this metal in the form of fine, metallic solid
droplets, scattered around the crucible. Presumably the metal passivated during 'flight' and the fine droplets cooled down too fast to burn in the
cold air.
Undoubtedly a specially formulated MnO2 thermite, perhaps with extra heat booster like KClO3/Al, can be made to shed most of its manganese as vapour,
possibly burning most of it too. But thermites designed to obtain lump Mn metal do work too, if you can live with poor yields. I've got the metal to
prove it too...
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Töilet Plünger
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Adding permanganates can cause more manganese to boil off - I recall seeing a video by MrHomeScientist which included permanganate as a
MnO2 thermite booster. It reduced the yield of lump metal significantly.
I don't think iron can reduce manganese compounds to the metal in a thermite, so Al or Mg is the way to go.
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blogfast25
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| Quote: Originally posted by Töilet Plünger | Adding permanganates can cause more manganese to boil off - I recall seeing a video by MrHomeScientist which included permanganate as a
MnO2 thermite booster. It reduced the yield of lump metal significantly.
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Permanganate would be an ideal heat booster if you really want to achieve maximum temperatures with MnO2 thermite. K2Cr2O7 works very well with
Cr(III) thermite.
With Mg, MnO2 might form a flash powder. Iron? Will need to look into that but my guess would be 'no'. This apart from alloying problems...
[Edited on 7-4-2014 by blogfast25]
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Dan Vizine
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I have obtained Manganese as a heavy, silver powder from MnO2/Al. Apparently by condensation of manganese vapor. This was the singularly most
spectacular Thermite reaction that I ever saw. Nearly explosive. Mixture of finely powdered reagents from that old prep lab...
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blogfast25
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It could be contemplated to try and formulate the thermite so that vapourisation of the Mn is maximised and the vapour then condensed. No sinecure
either, though...
No matter how you run them, spectacular they are: huge flame making it look like an inverted rocket motor. But I'm not really into pyrotechnics...
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elementcollector1
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Does manganese dioxide react with oxalic acid on its own? I would think that it makes manganese carbonate or even oxalate, but I'm not sure. I'm
trying to think of more efficient ways to 'process' battery paste into usable manganese compounds, and the carbonate is a great starting point for
salts and the oxalic acid would dissolve any iron present.
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blogfast25
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EC1:
The oxidation of oxalic acid to CO2 and reduction of MnO2 to Mn II requires extra acid (do the redox equation). I suppose you could use oxalic acid as
the extra acid, thus obtaining Mn II oxalate.
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MrHomeScientist
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| Quote: Originally posted by blogfast25 | | No matter how you run them, spectacular they are: huge flame making it look like an inverted rocket motor. But I'm not really into pyrotechnics...
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Spectacular indeed! A picture of one of my first MnO2 thermites became my YouTube icon. This was in a tiny flower pot and produced a column
of flame several feet high!
I've also been able to recover small bits of elemental Mn from these thermites, and as blogfast said the yields are pretty poor. Enough for my element
collection, though!
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elementcollector1
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I couldn't even get my thermites to light... Of course, that was before I started using sulfur and aluminum booster mix instead of KMnO4
and Al. Best thing is, the sulfur's recoverable; just mix the slag with water and lead the resulting gas through bleach.
I have yet to try a Mn thermite, but seeing as I already have a Mn sample, there's not much point. Might do it for fun, though.
blogfast25:
That might work. I'll have to give it a shot once I work up enough battery paste, as I recently discovered a trash bucket full of dead batteries at
the local hardware store and am waiting for someone to discard a 6V zinc-carbon cell.
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Bert
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Looks like a rocket?
Hell, I have MADE rocket engines using Al/MnO2.
The Mn definitely does burn in the air then- And the rockets tend to come down with their sticks on fire.
[Edited on 10-4-2014 by Bert]
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Oscilllator
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| Quote: Originally posted by elementcollector1 | | Does manganese dioxide react with oxalic acid on its own? I would think that it makes manganese carbonate or even oxalate, but I'm not sure. I'm
trying to think of more efficient ways to 'process' battery paste into usable manganese compounds, and the carbonate is a great starting point for
salts and the oxalic acid would dissolve any iron present. |
Yes. when making MnSO4 from MnO2, oxalic acid and H2SO4 I added the oxalic acid first and a vigorous reaction occured producing a pale powder. Upon
addition of the H2SO4 manganese sulfate was formed.
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blogfast25
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Lemmeguess: superfine ingredients and some heat boosting system, KMnO4 or KClO3/KClO4?
That Mn may burn in your conditions but it clearly didn't in mine. But my objective was to run that thermite as cool as
possible to maximise Mn in the melt.
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Bert
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Yes, as far as the particle size-
Very finely powdered manganese dioxide, ceramics glaze material. Pyrotechnic flake Aluminum, of a type used for flash powder. Sold as "American dark",
don't recall the manufacturers number or a mesh/micron size at the moment.
No additional ingredients beyond a stoichiometric MgO2/Al mix in the fuel grain. Ignition required either commercial "thermolite" fuse or other high
temperature methods. Mere black match or visco fuse did not work. Rockets were made on standard black powder core burning engine tools. Roughly
similar Isp, similar operating pressure as far as we could tell. Lower performance than a similarly sized black powder motor due to the heavier fuel
grain and exhaust gas.
Isp = Specific Impulse
[Edited on 11-4-2014 by Bert]
Rapopart’s Rules for critical commentary:
1. Attempt to re-express your target’s position so clearly, vividly and fairly that your target says: “Thanks, I wish I’d thought of putting it
that way.”
2. List any points of agreement (especially if they are not matters of general or widespread agreement).
3. Mention anything you have learned from your target.
4. Only then are you permitted to say so much as a word of rebuttal or criticism.
Anatol Rapoport was a Russian-born American mathematical psychologist (1911-2007).
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blogfast25
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| Quote: Originally posted by Bert | Yes, as far as the particle size-
Very finely powdered manganese dioxide, ceramics glaze material. Pyrotechnic flake Aluminum, of a type used for flash powder. Sold as "American dark",
don't recall the manufacturers number or a mesh/micron size at the moment.
No additional ingredients beyond a stoichiometric MgO2/Al mix in the fuel grain. Ignition required either commercial "thermolite" fuse or other high
temperature methods. Mere black match or visco fuse did not work. Rockets were made on standard black powder core burning engine tools. Roughly
similar Isp, similar operating pressure as far as we could tell. Lower performance than a similarly sized black powder motor due to the heavier fuel
grain and exhaust gas. |
Isp?
But I have to say I didn't know that thermite had been researched as rocket motor fuel...
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