RogueRose
International Hazard
Posts: 1590
Registered: 16-6-2014
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Lead acid battery plate decomposition by heat & O2
From what I have read and personal experience it seems that lead acid batteries are a mix of lead, lead sulfate and either lead oxide or dioxide.
Here are the properies and characterists of the various forms of lead found in these batteries:
Lead - Pb - MP 621F, BP 3,180F
Lead (II) Oxide - PbO - MP 1,630F BP 2,691F
Lead Dioxide - PbO2 - MP 554F (Decomposes) to (2)PbO + O2
Lead (II, IV) Oxide - Pb3O4 - PbO + O2 at 450-480C to Pb3O4
Lead Sulfate - PbSO4 - MP 1,989F Decomposes to PbO + SO3, Dissolves in HNO3, HCl, H2SO4 & forms plumbate complexes with NaOH
and KOH
From what I can see the most difficult to break down will be the sulfate as it decomposes at almost 2,000F into PbO (Of course the SO3 is a bit of an
issue - but processed outside). I found that PbO can be broken down to pure lead with carbon monoxide. My question is whether I can add powdered
charcoal to moulten PbO and blow air across while stirring to create the CO (IDK how else to generate CO).
If there are any lead dioxides (II or IV) they should decompose to PbO as it is heated, is that correct?
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Sulaiman
International Hazard
Posts: 3631
Registered: 8-2-2015
Location: 3rd rock from the sun
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I think that there is antimony in the lead, and carbon black, barium sulfate and lignosulfonate in the paste.
https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery
CAUTION : Hobby Chemist, not Professional or even Amateur
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AJKOER
Radically Dubious
Posts: 3026
Registered: 7-5-2011
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Powdered charcoal I suspect will very quickly be burned off at elevated temperatures.
Perhaps pieces of coal, but that would introduce impurities (like sulfur, silica, iron, alumina and small amounts of mercury).
Always have direct gasification with CO, H2 or possibly methane (see this educational link to an experiment employing methane on heated copper (ll)
oxide at and its rapid reaction: http://www.rsc.org/learn-chemistry/wiki/Expt:Reduction_of_copper(II)_oxide_with_methane ).
[Edit] Here is a reference, per a google extract, which appears to suggest adding 1% ZnO (or, in our case, perhaps just Zn) to a PbO reduction in CH4:
"Kinetic study and mathematical modeling of the reduction of ZnO-PbO mixtures by methane", H Ale Ebrahim, E Jamshidi - Industrial & engineering
chemistry …, 2005 - ACS Publications, ... Our experiments also indicated a relatively slow PbO reduction by methane ... PbO pellets with 1% ZnO were
produced (with PbO* symbol) and reduced by methane ... quickly 13 because ZnO can convert methane into CO + 2H 2 , which would then reduce PbO."
[Edited on 2-12-2016 by AJKOER]
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