Sciencemadness Discussion Board

Cleaning Zinc Cells

toothpick93 - 19-6-2013 at 22:23

I just dismantled a Lantern battery to get the zinc. I've removed the Manganese Dioxide out of it so I'm now left with a empty zinc cell, but a lot of manganese dioxide is still on the sides of the zinc. Is there a way i can remove the manganese dioxide with out dissolving the zinc? any acid or base? or should i just scrub it off?

ScienceSquirrel - 20-6-2013 at 03:56

Go and see a friendly roofer, he will sell or give you a piece of zinc sheet, 99% pure.

blogfast25 - 20-6-2013 at 03:57

Quote: Originally posted by toothpick93  
I just dismantled a Lantern battery to get the zinc. I've removed the Manganese Dioxide out of it so I'm now left with a empty zinc cell, but a lot of manganese dioxide is still on the sides of the zinc. Is there a way i can remove the manganese dioxide with out dissolving the zinc? any acid or base? or should i just scrub it off?


Just scrub it and sand it down till it gleams (for not very long). With an MP of 419 C it can be easily ingoted, most oxidic impurities will then float on top of the molten metal. Ingots tarnish less than sheets of course (less surface area per gram).

Note also that what you deferentially called 'Manganese Dioxide' over here we call 'battery crud' because it contains often less than 30 % MnO2 (and usually as mixed Mn oxides) and is contaminated with large amounts of graphite (conductor), almost always some ferric oxide, some zinc oxide or zinc chloride etc.

[Edited on 20-6-2013 by blogfast25]

papaya - 20-6-2013 at 06:12

Try oxalic acid.

toothpick93 - 20-6-2013 at 08:12

I new that the manganese dioxide is very crude, so much iron its not funny. Would oxalic acid only dissolve the dioxide?

blogfast25 - 20-6-2013 at 09:15

Quote: Originally posted by toothpick93  
I new that the manganese dioxide is very crude, so much iron its not funny. Would oxalic acid only dissolve the dioxide?


It's likely to dissolve also some, if not all, of the iron. I used the oxalic acid method once to reduce the battery crud 'MnOx' to Mn2+ (the oxalic acid oxidises to CO2) and found considerable amounts of iron in the leachate. It might seem strange because ferric oxalate is poorly soluble but oxalic acid isn't the only acid in the mix: the reduction needs to be carried out in the presence of H2SO4, which largely suppresses to dissociation of the oxalic acid. No oxalate ions, no ferric oxalate.

Iron and manganese can be separated in ways that have basically already been discussed to death on this forum. Use the search facility...

Quote: Originally posted by papaya  
Try oxalic acid.


It's likely to attack the zinc.

Quote: Originally posted by ScienceSquirrel  
Go and see a friendly roofer, he will sell or give you a piece of zinc sheet, 99% pure.


True but zinc metal and MnSO4 from dry batteries... that's a bit of a rite of passage! :D The graphite just gets everywhere if you're not diligent, especially when wet.



[Edited on 20-6-2013 by blogfast25]