I cleaned the MnO2 paste and carbon electrode out of the zinc casing of a zinc carbon cell and decided to oxidise the zinc with H2SO4. I put the cell
in a beaker and added some fairly concentrated H2SO4 solution and let the acid oxidise the outer surface of the zinc casing. I then dropped a mL of
acid into the inside of the zinc casing and instantly I heard hissing and got a whiff of H2S. There was still some MnO2/ZnCl paste in there. Did the
H2SO4 oxidise the MnO2?plante1999 - 23-1-2011 at 09:48
lantern batery cell have a very high content of NH4Cl and carbon i think the H2SO4 reat with The NH4Cl. blogfast25 - 23-1-2011 at 10:14
MnO2 with concentrated (or at least 50 w%) H2SO4 actually reduces MnO2 to Mn3+ (Mn +III) with oxygen as a by-product. Search for it on SM and yee
shall find (numerous threads).Arthur Dent - 23-1-2011 at 10:53
Yup, there are indeed numerous threads on harvesting components from old Zn/C batteries.
If your goal is to produce Zinc sulfate, my suggestion would be to start off with the cleanest zinc possible. If you just 'dug out' the MnO2/C paste
and left some of it in the empty battery shell, it'll mess up your reaction. I suggest that you cut-up the casing and flatten it so that you have a
strip. Then, clean it up with a wire brush to remove the battery crud and electrolyte.
Then dip your zinc strip briefly in concentrated hydrochloric acid (a minute at the most) so that all the remaining impurities are removed, then rinse
it thoroughly. At that point, your Zn strip will be clean enough to produce fairly pure Zinc Sulfate. Always remember that to have pure reagents, you
must start off with clean/pure chemicals that have as little contaminants as possible.
If your goal is to produce Zinc sulfate, my suggestion would be to start off with the cleanest zinc possible.
I was just testing it out but I was wondering how I could clean the zinc obtained from lantern batteries, thanks. White Yeti - 16-8-2011 at 11:48
Why mess around with sulfuric acid? Dip the zinc into a solution of copper sulphate (if you can obtain the acid, obtaining root killer shouldn't be a
problem). You will get a clear solution of zinc sulphate with a mass of spongy copper as a useful side product.
