Can Reverse Polarity Charging Convert Old Lead Acid Batteries into Pure Pb?

[Ayman Saif]

Hello,
according to the lead acid battery standard equations
The overall chemical reaction is:

At the negative terminal the charge and discharge reactions are:

At the positive terminal the charge and discharge reactions are:

My Q?
If we empty all liquid from old battery and add H2O (water)
then charge with reverse polarity
can we get pure PB?

 

[Vanadium 50]

Real batteries have a more complex set of reactions, so it is unlikely that anything depends on this simple set will work. Besides that, the lead plates are not elemental lead - the lead has been alloyed, most likely with antimony or calcium.

 

[Martin0001]

Lead in batteries is a sponge.
If I am to "reprocess" battery somehow, assuming that it is old, useless battery, I would remove electrodes, pour acid away, wash electrodes well with water , dry them well and simply smelt.
On the bottom would be molten lead and on the top some floating crappy. mostly PbSO4.
Such lead would not necessarily be a pure element, some alloyed additives, up to 2-5% of total mass could be left.

 

[Ayman Saif]

Martin , You are right that is good way , but smelting will produce more than 5% PbSO4 , maybe 20% , and that is my target how to recover this part and not loose

 

[Martin0001]

There is a way to convert most if not all PbSO4 into Pb during smelting by adding some charcoal and sodium carbonate into the mix.
At 800*C chemistry is as follows:
PbSO4 + C ---> PbO + CO + SO2
PbO + CO ---> Pb + CO2
PbSO4 + 4C ---> PbS + 4CO
PbS + 2PbO ---> 3Pb + SO2

It is important not to add too much carbon because some PbS may not find enough of oxygen in the mixture to undergo the last reaction.
Presence of sodium carbonate reduces formation of PbS and possibility of said nuisance, hence yield of metallic lead is increasing.
https://www.researchgate.net/publication/244733490_Reduction_Behavior_of_Lead_Sulfate_in_the_Presence_of_Solid_Carbon
I would say that this approach is a way forward.