# Sulfuric Acid from Dead Car Batteries



## kernels (Jul 23, 2016)

Hi guys, 

When it comes to precipitating lead from solutions with sulfuric acid, would it be OK to use some acid recovered from DEAD car batteries, or does the process that kills the batteries also affect the sulfuric acid in them making it unfit for this purpose ? 

Thanks!


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## Barren Realms 007 (Jul 23, 2016)

The solution is fine to use for processing.


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## myfalconry76 (Jul 23, 2016)

Go to the local recycling yard, the by my place has let me drain as many batteries as I want for free.


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## jason_recliner (Jul 23, 2016)

The only caveat is that electrolyte in dead batteries is almost entirely water; most of the sulphur will be in the lead plates as lead sulphate PbSO4.

Once you gather it all up and filter it well, you can weigh a known volume to determine the S.G. and thus its concentration. And from there, decide whether it's worth evaporating up to a workable concentration, say 30%. Read about the hazards of SO3 first!

It would be an interesting exercise.

On the other hand, if you have an automotive hydrometer you can test, on the spot, whether each cell is even worth collecting.
Edited to add link


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## kernels (Jul 24, 2016)

Great, thanks for the advice guys, I will probably invest in the automotive hydrometer as I have a relatively large number of batteries waiting in storage for scrap prices to improve a little bit, should be able to get some semi useful acid!


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## rickbb (Jul 25, 2016)

As cheap as battery acid is I have to wonder if it's worth the trouble.


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## resabed01 (Jul 25, 2016)

Take the batteries in for scrap lead and with the money buy some acid. I bought a 20l container of battery acid from NAPA for about $35 some years ago.


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## kernels (Jul 25, 2016)

Yeah, it's weird how in some places Nitric is hard to find, but no problem for me to buy online, Sulfuric seems to be harder to buy than Nitric here in New Zealand. I will contact a few chem suppliers. Thanks guys.


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## Geo (Jul 26, 2016)

With evaporation and dilution, the sulfuric acid can be collected made usable.


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