Upsilon
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Making manganese salts from manganese dioxide
What are some effective methods of making a water-soluble manganese salt from manganese dioxide? So far I have tried hydrochloric acid to make
MnCl2, but I don't like doing it that way at all. I used just small amounts to test it; it kept going for hours, generating a billowing
cloud of gagging chlorine gas (don't worry, I put it outside, far from anything).
I could go with other acids instead of hydrochloric, but these would take even longer (at least not generating a crapload of toxic gas in the
process). I'm thinking sulfuric is the way to go, though this apparently requires heating. I've also looked into electrolysis processes that can
reduce it to an Mn2+ salt but I can't seem to find a lot of information on how this works. Anyone have some advice?
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DraconicAcid
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You just have to add a reducing agent. Hydrogen peroxide works.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Oscilllator
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Another thing that works (and is probably cheaper) is Oxalic acid. It also has the advantage of coming as solid crystals, so you don't have to work
with dilute solutions.
There's a NurdRage video on this process somewhere, is you want more information.
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Upsilon
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Quote: Originally posted by Oscilllator  | Another thing that works (and is probably cheaper) is Oxalic acid. It also has the advantage of coming as solid crystals, so you don't have to work
with dilute solutions.
There's a NurdRage video on this process somewhere, is you want more information. |
I was considering this as well, but I feel like this would take a long time like the other reactions with acids. I'll try to find the video though.
[Edited on 17-9-2015 by Upsilon]
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j_sum1
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Nurdrage has several great videos on this. The trick is to eliminate the Fe impurities that are nearly always present.
The method I like best is where he (cleverly) bubbles some SO2 through his solution. I will let you find it.
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Upsilon
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| Quote: Originally posted by j_sum1 | Nurdrage has several great videos on this. The trick is to eliminate the Fe impurities that are nearly always present.
The method I like best is where he (cleverly) bubbles some SO2 through his solution. I will let you find it. |
Yes, I've found the video. The manganese dioxide I have though is technical grade that I got online, so I don't think it would be nearly as
contaminated as the stuff he got from the batteries.
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Volanschemia
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I may be wrong, but isn't Technical Grade < 90% purity?
"The chemists are a strange class of mortals, impelled by an almost insane impulse to seek their pleasures amid smoke and
vapor, soot and flame, poisons and poverty; yet among all these evils I seem to live so sweetly that may I die if I were to change places with the
Persian king" - Johann Joachim Becher, 1635 to 1682.
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DraconicAcid
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I am not sure if I'm remembering correctly, or if I'm as drunk as aga, but I seem to recall once boiling MnO2 with alcohol and an acid to get the
Mn(II) salt. Cheaper than oxalic acid, and then you don't have to worry about getting rid of the excess reducing agent.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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Oscilllator
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DraconicAcid's idea sounds great, but just FYI the reaction with oxalic acid is extremely vigorous. I remember I made the same assumption as you when
I did this, so I added the MnO2 and oxalic acid together then added some water. The reaction started quickly and heated up enough to boil vigorously
for a while so you won't have any troubles there. You may even wish to add the MnO2 to the oxalic acid solution slowly to avoid spattering.
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Upsilon
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| Quote: Originally posted by Oscilllator | | DraconicAcid's idea sounds great, but just FYI the reaction with oxalic acid is extremely vigorous. I remember I made the same assumption as you when
I did this, so I added the MnO2 and oxalic acid together then added some water. The reaction started quickly and heated up enough to boil vigorously
for a while so you won't have any troubles there. You may even wish to add the MnO2 to the oxalic acid solution slowly to avoid spattering.
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You're referring to the reaction in NurdRage's video that includes the sulfuric acid, right? Not just with MnO2 and the oxalic acid?
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