Sciencemadness Discussion Board

recover manganese form carbon-zinc battery ?

iloveloli - 16-8-2016 at 09:25

i find some of it which is already had liquid leaking out
so broke them and get the black power out
the black powder should be MnO2, Mn2O3, C and some zinc ion (i don't know if there are mercury in it because the package just said "low" mercury.....)

then, put the powder in dil.H2SO4 to get all zinc ion out
filter out the powder and put in conc.H2SO4 and heat a little bit
all manganese should be dissolve
then adding water to dilute it and filter again
i don't why but a red solution is coming out.........
adding the red solution to excess of sodium bicarbonate solution
and then some pale orange ppt come out........

why orange??
did anyone know?
manganese(II) carbonate should be white......
i hope it won't be mercury.........

Zandins - 16-8-2016 at 09:39

I don't really understand what you are trying to accomplish. The most straightforward way to purify the MnO2 paste would be to mix it with water, as the contaminants (NH4Cl, ZnCl) are soluble.
To extract manganese from the resulting manganese dioxide , the standard method would be a carbothermic (with carbon) or magnesiothermic (with powderer Mg) reduction.
Perhaps if you added equations and more comprehensible descriptions, I would be able to help you better.

[Edited on 16-8-2016 by Zandins]

zwt - 16-8-2016 at 10:14

There isn't a meaningful (read: detectable by qualitative analysis) amount of mercury in zinc-carbon batteries, so don't worry.

The orange may be iron contamination present in the battery paste. If your sulfuric acid was drain opener, it could be from that too. You can use NurdRage's method to make pure manganese sulfate and re-precipitate the manganese with carbonate.

Quote: Originally posted by Zandins  
I don't really understand what you are trying to accomplish. The most straightforward way to purify the MnO2 paste would be to mix it with water, as the contaminants (NH4Cl, ZnCl) are soluble.

Carbon and iron oxides aren't soluble in water or any common solvent.

[Edited on 16-8-2016 by zwt]

zwt - 16-8-2016 at 10:51

Also:
Quote: Originally posted by iloveloli  
then, put the powder in dil.H2SO4 to get all zinc ion out
filter out the powder and put in conc.H2SO4 and heat a little bit
all manganese should be dissolve

Manganese dioxide won't really react with sulfuric acid. NurdRage has a video on that too. You probably dissolved mostly iron oxides and other manganese compounds.

[Edited on 16-8-2016 by zwt]