Sciencemadness Discussion Board

reduction of manganese dioxide with aluminium

shaheerniazi - 30-11-2013 at 23:28

I want to know that if I melt aluminium powder and sprinkle Manganese dioxide on it will the thermite reaction take place and give me these results:

MnO2 + Al -----> Mn + Al2O3 ?

elementcollector1 - 30-11-2013 at 23:45

1) Could just melt any old source of aluminum, really. Powder might just burn in air anyway.
2) Yes, it would. However, due to the temperature of the reaction (thermites are very hot) and the boiling point of manganese metal, your Mn will boil long before you get any yield. Thus, you need something inert to lower the reaction temperature - CaF2 is a good start.
See http://developing-your-web-presence.blogspot.com/2008/07/man... (written by blogfast25!) for more information.

shaheerniazi - 30-11-2013 at 23:57

Though I even have some Mn2O3, and If I do the reaction in a hood then will the evaporated metal cool and solidify on it?

shaheerniazi - 30-11-2013 at 23:59

Though what temp will be needed for the reaction with carbon and MnO2:

MnO2 + C -----> Mn + CO2

elementcollector1 - 1-12-2013 at 00:09

Quote: Originally posted by shaheerniazi  
Though what temp will be needed for the reaction with carbon and MnO2:

MnO2 + C -----> Mn + CO2

A very high one, and the Mn is sure to boil off if you use carbon.
If you do the reaction with some structure over it (not a fume hood - how would this hold up to gaseous manganese?) You might get some metal. Keep in mind that if molten manganese is reactive towards oxygen (which it very much is, more so than any of its periodic neighbors), gaseous manganese will be doubly so. You would have to have a very low distance between your condensing surface and reaction, while still keeping it cool enough to allow the manganese to condense in the first place (it will undoubtedly heat up from such an exothermic reaction).
Better to go with a powdered heat-sink - more yield, less complexity.
You have Mn2O3? Where did you get this? Is it pure?

shaheerniazi - 1-12-2013 at 00:16

http://www.sciencemadness.org/talk/viewthread.php?tid=27603