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Extracting lead from car batteries? Answered

I have a couple of battered old car batteries. There is no local scrap dealer that will take them so I was wondering if it would be possible to extract the lead myself and sell it for scrap. I have searched on google and cannot find anything about this and I suspect it would be dangerous and impractical. However I thought there's no harm in asking here. I was imagining that I could open the battery up and pour the acid into some kind of strong alkali, neutralising it to make it safe for disposal. But then, I certainly wouldn't like to try this without some advice first.


As NM and others have commented, it is quite difficult to handle lead safely.  For U.S. readers, here is OSHA's information on lead exposure.  And here is an HTML version of the MSDS.

The bottom line?  If you have not had training in how to handle lead (what PPE, what exposure levels are safe, what mitigation strategies to employ, etc.), you really should not be attempting this.  Like rewiring your main breaker panel, this is one of those "do not DIY!" projects.

I tore down a couple batteries yesterday... I like to reclaim the acid so I place the battery into a heavy walled plastic lug on a board. The board is just in case I miss/glance when I strike the bottom edges and corners of the battery with a chisel and drain it. Once drained, I submerge the battery in a mix of sodium bicarbonate and water untill it stops reacting.

Once the battery stops reacting, I just chisel the puppy open and start pulling out the guts to melt down.

I see a comment below about an explosive reaction with sodium hydroxide... No idea, I use good old baking soda (sodium bicarbonate) and never had a problem, even if added directly to sulfuric acid.

I've got one, which I was thinking of making an Instluctable from. But I hsaven't finished yet,.


Looking forward to it, lemonic...? :)

Dilute the dickens out of that battery acid with water; adding an alkali to battery acid will make it "explode", scattering toxic, burning material everywhere. I watched a chem student try to neutralize a spilled beaker of sulfuric acid with sodium hydroxide, ducking behind a lab bench as I screamed "NO!" Had it not been for an alert grad student to pull her under the lab shower, she would have been scarred for life. The reaction was violent and instantaneous. Mix the water in slowly - old acid can be very concentrated, and the heat of hydration can boil the solution. Once well diluted, neutralize slowly with a well-diluted alkali solution, and dispose of the precipitated salts properly. Save your eyes.

Never, ever add water to a concentrated acid!!
You mention the sodium hydroxide reaction - it only tells me the person doing it was brainless and used a concentrated mix.
With your suggestion of adding water the water can boil into steam instantly - something you don't want....
The only half-way safe way I can recommend is to use a battery hygrometer or similar to remove the acid from the battery and then to add the acid to some really cold water and doing this slowly.
In any case I would not even attempt to get lead from old batteries as far too many toxins are involved, not to mention the hazards for the enviroment.

Yes - she, a freshman Chem student, just reacted without thinking at all; she had spilled 4M lab acid out of a glass reagent bottle by knocking it over. And grabbed a bottle of 4M Sodium Hydroxide to neutralize it. Do the math, and you'll know what the explosion was. I was about 12 feet away, knew what was in the bottles, knew what was about to happen when I saw her tip the NaOH, and ducked; the sound was like an arcing short in a high voltage line. Unforgettable.

But this is battery acid - not concentrated sulfuric. People add water to batteries all the time - but you still do it slowly, as I suggested, to minimize total heat of hydration release and spatter. That said, if you were diluting concentrated Sulfuric - or any other strong acid - you absolutely would add the acid to the water, not vice versa.

Incidentally, I'm talking about IF the acid is still in the battery, and you're filling it through the caps. In an open container, proper practice always dictates that the acid be added to the diluent water. You only get one set of eyes.

Take old batteries to a car parts place. They'll give you a receipt which is good for deferring cost of a new battery.

Googled cost of lead.

About 10 cents a pound.

3 batteries might net u 10 bucks.

.  It is very difficult to handle lead in a safe manner, especially if you plan on melting the lead. If you melt it, you have lead fumes to worry about (plus fuel costs). If you don't melt it, you still have gloves and other protective clothing to dispose of.
.  The sludge (lead sulfide/sulfate/sulf?) may be difficult to process into elemental Pb without creating pollutants and/or using a lot of energy.
.  For small amounts, it just isn't worth the risk. Looks like scrap Pb is selling for about 0.50 USD/lb (but I didn't look very closely).

Egads, is that my problem ?   When I was younger, I not only played with raw mercury,  but made a whole bucket load of sinkers out of a large lead brick......*sigh* 

I used to sell lead by the pound, as flashing for roofs and windows.  We used to unroll the lead sheet with bare hands, cut it with a knife, and roll it up again.

The metal is mostly dangerous if formed into pellets and fired at high velocity.

To process the sludge, I'd dry it, then heat it in air (say, in a clay plant-pot in the coals of a barbecue) to turn the sulphides into oxides, then stir in some powdered unburned charcoal, add a lid and heat again.

If you've remembered to put a collecting vessel under the hole in the plant-pot, you'll collect molten metallic lead.

OK, it's a bit smelly when you roast off the sulphides, but just do it outdoors.

That is excellent info not easily found! Thank you.

Modern batteries have very thin plates that sulfate all the way through. With this info I can turn old batteries into new home made ones (that will live longer).

back in my teens, when I melted the lead for sinkers,  I did it in the basement ....*sigh*

Lead melts at about 620F, but vaporizes at 3100F. That's a lot of safety margin. It's safe to melt, but I do suggest doing it in a well-ventilated area with personal protective equipment (smock, gloves, face guard).

All in all, it would be far better environmentally to hand them off to a garage or other business that can better dispose of them than to attempt to personally recycle the batteries. As evidenced by lemonie's comment about "lots of lead-sludge"

The amount of money you would garner by selling the recovered lead is imo far outweighed by the environmental damage you're likely to do in the process of extracting them.

I'll agree, if the thing is old it'll be sludgy... but I have a facility for the sludge (or so I've been told).


well, if that's the case, but the author said he had no recycling facilities nearby...

eh...No offense intended, but I still feel that  the profits from such work still  far under-weigh the potential for environmental damage, especially if one needs to ask how to reclaim the lead in a garage setting. I'm of the mind to leave the battery recycling to the professionals, since their facilities are mandated by fed law (in the US) to maintain a certain level of "hygiene" that few individuals will be able to match. I expect the laws are equally or more stringent in the UK and elsewhere in the EU.

(on a personal note: I realize the material disposal laws are less strict for individuals than they are for corporate level players, at least in the USA, but imo, using that excuse in cases like toxic battery packs is really stretching the loophole. a dried 1/2" deep can housing the bit of house paint is one thing, and it's exactly  the quasi draconian situation the law was designed to prevent .  but batteries are entirely another. Yeah, one battery is nothing, but multiply that by 300+ million individuals and you get one huge, steaming pile of             sheesh)

blahblah mode off.

I wanted the lead and acid. Yes I'll agree with you otherwise.


I figured as much, and what's more, I'm aware of your abilities, so I have a certain confidence that you're not going to pour it down the drain or into a field because you can't find an appropriate disposal site. Not to say that the author would either, but in a general sense I don't trust people to do the right thing when no-one's looking or the law has a loophole that says they can (even if they shouldn't).

And obviously, there's a cool factor to learning directly about the innards of the beasties  Gotta love empiricism ;-)

I might finish the job off today... It had been dumped and was cracked, so I view this as a clean-up of sorts.


I'm most of the way through doing this. Draining is OK, extracting is hard work, my problem is that I've got a lot of lead-sludge that needs disposing of...



I think you missed the step where the lead ingot turns to gold bullion.


8 years ago

Cheers folks. I will definately not attempt it.

Yeah I did read a couple of those stories during my search. Rest assured I am not going to attempt this unless I can find a totally safe method. Both for me and the environment.