Sciencemadness Discussion Board - Extracting lead from car batteries

Extracting lead from car batteries

Zinc - 16-5-2008 at 13:23

We have accumulated a large amount of old car batteries. They are in all sizes. From small that weight around 6-7 kg to large ones that are 60-70 kg heavy. We have already poured the acid from them. Now as they contain a lot of lead in them we would like to extract it. What would be the best method to do that? I was thinking of cutting the top off with an angle grinder, remove the top with all of the plates attached and then remove one by one with a saw (not with an angle grinder because it would spread lead dust all over the place). Also as there is PbO2 in there also what would be the best method from keeping it from flying all over the place while removing the lead plates?

ShadowWarrior4444 - 16-5-2008 at 13:35

Blowing them up would certainly extract the lead from them! (joke in poor taste)

More seriously: If they are completely discharged, which I would hope they are before you start sawing at them, most of the lead should be the form of lead sulfate. If they’ve been discharged for a while, the lead sulfate should be crystalline and non-conductive. Then I'd suppose you would need to look up lead sulfate and the reactions necessary to reduce it to the metal. (I can't remember many at the moment.) You could engage in a bit of vitriol burning! [Possibly to recover the sulfuric acid.]

Zinc - 16-5-2008 at 14:04

Quote:

Originally posted by ShadowWarrior4444
Blowing them up would certainly extract the lead from them! (joke in poor taste)

I have considered that. And I think it is a very good idea!! But the problem is that the cost of the explosive would reduce the profit from selling the lead for scrap. But one battery is reserved for that (we will blow it up underground to reduce the noise and to prevent the parts from flying away)

Quote:

Originally posted by ShadowWarrior4444
More seriously: If they are completely discharged, which I would hope they are before you start sawing at them, most of the lead should be the form of lead sulfate. If they’ve been discharged for a while, the lead sulfate should be crystalline and non-conductive. Then I'd suppose you would need to look up lead sulfate and the reactions necessary to reduce it to the metal. (I can't remember many at the moment.) You could engage in a bit of vitriol burning! [Possibly to recover the sulfuric acid.]

I charge them before removing the acid to increase the acid concentration and the amount of lead in them. So they certainly contain some metallic lead.

Yes it would be nice to reduce the lead dioxide and sulfate to lead but I think that the cost of doing that would reduce the profit from the lead. But I will save the oxide and sulfate. It would be a nice experiment to reduce them to lead

tumadre - 16-5-2008 at 14:22

OMG *thinking back to my childhood lead experiences...

Alright. band saw, if you have one, or an 18 inch long hack saw works too, for removing the tops of the battery.

If most of these cells are in really bad shape, you may not be able to separate the grid from the active material, if you can, you should separate the two, (make it easier to melt)

Are you thinking of reducing all the lead oxide/sulphate with aluminum?

12AX7 - 16-5-2008 at 14:26

Heap in a lead smelter with all the other ore. The stack scrubbers will take care of particulates, sulfur oxides and the combustion will take care of the burning battery case (which is probably HDPE).

The easiest way to do this is to give the battery to a *battery recycler*, which is the recommended disposal method for lead-acid batteries, and all other batteries for that matter.

Tim

Zinc - 16-5-2008 at 14:44

I don't have a band saw but I have a hack saw so then I will use that.

I could give them to the recycler but then they only give you 4 cents per kilogram and for lead 62 cents per kg.

vulture - 16-5-2008 at 15:02

Quote:

Have you ever considered that lead is a toxic heavy metal and that you will severely contaminate the ground(water) in this way? I'm getting really fed up by your irresponsible behaviour. :mad:

It seems like you're using home chemistry as a front for relieving your adolescent urges. Try sports or a girlfriend for that instead of giving us a bad name. :mad:

ShadowWarrior4444 - 16-5-2008 at 15:07

Quote:

Originally posted by vulture

Quote:

Have you ever considered that lead is a toxic heavy metal and that you will severely contaminate the ground(water) in this way? I'm getting really fed up by your irresponsible behaviour. :mad:

It seems like you're using home chemistry as a front for relieving your adolescent urges. Try sports or a girlfriend for that instead of giving us a bad name. :mad:

You could at the very least attempt to design weapons, Zinc. Blowing things up for fun can be a thrill, but it is quite cheap; now designing various cannons and missile systems is fun, and can be profitable. (Its been a nice hobby of mine, along with a vast variety of other things.)

My personal favorite (for now) is probably the bromine-water-pistol. *giggles wildly*

Zinc - 16-5-2008 at 15:14

Quote:

Originally posted by vulture
Have you ever considered that lead is a toxic heavy metal and that you will severely contaminate the ground(water) in this way?

Yes I have considered that. That is why It will be done far away from any cultivated land. And we will remove the lead (and other parts) from the ground. And those 200-300 g of powdered lead oxide and sulfate that remain wont do any harm to the tones and tones of earth in which they will rest. It is a too small quantity to do any harm to the ecosystem.

[Edited on 16-5-2008 by Zinc]

Mr. Wizard - 16-5-2008 at 16:24

A couple of points:
1 Charge the batteries before draining the acid. You get pure lead from the sulfate on one electrode and less SO2 + SO3 into the air. If you want to collect the H2SO4 you get more of it.
2 Flush the cells with clean water after dumping the H2SO4, you can get more of the acid out. Boiling the flushed water will concentrate the acid.
3 Use an air chisel on the battery case. Use eye, ear, and respiratory protection. An air chisel will make short work of the case. It is easy to keep the edge of the chisel out of the plate material. The air chisels are very cheap.
4 Be aware the battery plates will produce SO2 and acid fumes when melted. It stinks and will irritate the hell out of anybody down wind. They will call the authorities. It won't take a Sherlock Holmes to find the source.
5 The Lead will not be pure, it will be contaminated with Antimony and Calcium which are used in the battery. The Calcium metal will liberate Stibnine gas if the dross or scum scraped from the molten metal is allowed to get wet.
6 Be careful adding wet or damp stuff to molten Lead. A little moisture forced below the surface of the molten Lead will launch a geyser of molten metal upward. Nothing wet into a hot pot should be the rule.

BromicAcid - 16-5-2008 at 16:43

Zinc, what country do you live in? In the state I used to live in you had to pay a deposit when you bought a battery, when you brought in a used battery to a scrap metal broker they bought it from you directly for the cost of deposit ($5.00) however after lead went up they started giving more, I think now it's up to $10 per battery.

Regardless, it might be worth it just to turn them in and avoid the hassle. The only easy lead to recover on a battery are the two contacts on the top, the rest is all holed up in the sulfates, dioxides, etc. You end up with a nasty paste and really not many recyclers just take random pastes. I know form experience how difficult it can be to disect one of these batteries and how messy it can be, really, consider just turning them in, that way you don't make a buch of waste to get rid of as well.

not_important - 16-5-2008 at 16:43

Quote:

Originally posted by Mr. Wizard
...
5 The Lead will not be pure, it will be contaminated with Antimony and Calcium which are used in the battery. The Calcium metal will liberate Stibnine gas if the dross or scum scraped from the molten metal is allowed to get wet.
...

I don't believe both are used together, if true it would be fairly simple to sort the batteries into Ca and Sb piles, and process them separately.

Second, this will only be true if there is metallic calcium in the dross, and well as a soluble antimony compound. Treating the dross with alkaline solution likely would prevent such a problem, that needs research. But you could also treat the dry dross with an oxidising flux, say Na2CO3 + NaNO3, to oxidise any metallic calcium.

-------------------------------------

There's a reason you don't get a lot for selling batteries to recyclers, in part because they need to control the release of SOx, lead, and HCl from any PVC used in the batteries.

With the proper installation you can drain and wash the batteries, then smelt them whole or after shredding. The plastics reduce the lead compounds to the metal, SO2 and HCl are scrubbed from the off gases. The slag is high in lead, and needs careful disposal or treatment as a source of lead - an "ore" - to recover most of the lead.

Saerynide - 16-5-2008 at 17:33

Be very careful opening lead acid batteries. If they are over charged, they can spray acid when you open them. Many a pour soul have gotten H2SO4 in their face as a result. I was about to open one a few years ago, but I realized I value my eyes and my face very much, and Id rather just buy the lead.

MagicJigPipe - 16-5-2008 at 17:40

Quote:

Have you ever considered that lead is a toxic heavy metal and that you will severely contaminate the ground(water) in this way? I'm getting really fed up by your irresponsible behaviour.

One lead battery. In the ground. How many thousands of tons of lead do you think are shot (by guns) into the ground in the United States? I'm pretty sure metallic lead in the ground isn't the main problem with groundwater pollution. Surely it's the salts and organics. That's only speculation though.

The pollution caused by burying a single battery in the ground is negligible especially if it is picked up afterwards. I understand your concern, vulture, but I don't think you should become "fed up" with him over this. I'm sure you've done irresponsible things in your life. Let's just try not to be like those old guys sitting around saying, "When I was a boy we had to walk to school, uphill both ways in the snow. You kids these days have no responsibility." Let's just inform him and be done with it, okay?

The only reason I would say "don't do it" is if it contained significant quantities of soluable lead salts.

Also, bromicacid, it's the same in my state. You get the 10 dollar deposit when you bring the old battery back. Me, I'd rather have the 10 bucks than the lead or the "satisfaction" of blowing it up underground.

EDIT
I changed my post above to better say what I really meant.

[Edited on 5-16-2008 by MagicJigPipe]

12AX7 - 16-5-2008 at 19:46

Quote:

Originally posted by vulture
Have you ever considered that lead is a toxic heavy metal and that you will severely contaminate the ground(water) in this way?

Actually, lead stays very well in place, bound to soil and as the carbonate, sulfate, sulfide, etc. I highly doubt groundwater will be a problem, even in the small area affected.

However, if the land is used much (e.g., cropland), THAT will be a problem.

Tim

BromicAcid - 16-5-2008 at 20:00

Regardless, lead is an EPA regulated metal. >5 ppm extractable lead relegates dirt as hazardous waste (per the TCLP). If a law enforcement agency ever wanted to get something on a chemist on this forum all they'd have to do is start digging around in their backyard and this sort of thing would give them plenty of ammunition.

tumadre - 16-5-2008 at 21:24

>5 ppm extractable lead relegates dirt as hazardous waste (per the TCLP).

funny, the concentration of lead in the earth's crust is 14.

ShadowWarrior4444 - 16-5-2008 at 21:31

Quote:

Originally posted by tumadre
>5 ppm extractable lead relegates dirt as hazardous waste (per the TCLP).

funny, the concentration of lead in the earth's crust is 14.

Under the new standards, lead is considered a hazard when equal to or exceeding: 40 micrograms of lead in dust per square foot on floors; 250 micrograms of lead in dust per square foot on interior window sills and 400 parts per million (ppm) of lead in bare soil in children's play areas or 1200 ppm average for bare soil in the rest of the yard.

-Residential Lead Hazard Standards
TSCA Section 403
(http://www.epa.gov/lead/pubs/leadhaz.htm)

BromicAcid - 16-5-2008 at 21:31

Exactly, and the permissable amount in dirt for areas where children can play is a few hundred ppm. But first this is the TCLP test, not just an overall lead test but extractable test, and additionally this only applies to materials that are being treated as hazardous waste.

http://www.ehso.com/cssepa/TCLP.htm

Quote:

40 CFR §261.24, outlines the 40 contaminants the TCLP analysis tests for (See Table 1—Maximum Concentration of Contaminants for Toxicity Characteristic). If a “Solid Waste” fails the test for one or more of these compounds, the waste is considered to be a characteristic hazardous waste – unless there is an exemption that applies. Bear in mind, too, that a characteristic waste may still also be a “listed” hazardous waste.

D008
Lead (Pb)
5.0 ppm

Again, I am talking about extractable lead with a TCLP test, but if you're tearing apart batteries the possibility for contamination is great and if someone classifies your contaminated soil as waste material, you could be in trouble.

[Edited on 5/17/2008 by BromicAcid]

MagicJigPipe - 16-5-2008 at 21:33

I was just about to say something about that. What about the lead sulfate, sulfide and carbonate that's exists throughout the Earth's crust? I'm sure there's even a little natural elemental lead.

I doubt he is detonating his explosives on land that is used for crops but I could be wrong.

Also, how would the government determine if the lead was either put there by someone else or natural? I mean with absolute certainty (not that that matters). I would not put it past them to pull something like that out of their asses though. I wonder how many "non-chemist's" back yards have an unacceptable amount of Pb? I bet more than you'd think.

EDIT
I forgot to mention sinkers used for fishing. I mean, these go directly in the water. I think lead is so insoluble that it's not a big deal.

[Edited on 5-16-2008 by MagicJigPipe]

BromicAcid - 16-5-2008 at 21:40

Regardless, the fact remains that contamination is a possibility, expecially if you are just dumping the acid. And although the environment could technically take one for the team, it is something that would be frowned upon.

My previous statements still stand with regards to just recycling the things and getting it over with, it's not something I normally say. Normally I am gung-ho about doing things at home, making my own reagents, and I would call someone saying the same things as me unmodivated and not participating in discussion in the spirit of this forum, but really, it seems there would be eaiser ways to make the money.

ShadowWarrior4444 - 16-5-2008 at 21:55

I don't particularly have a problem with disassembling old batteries for reagents, whether from a car or those pretty graphite electrodes from dry cells. Blowing one up *may* be a waste, unless you were testing a novel weapon system based on a car battery, or car battery housing.

As for the TCLP test: It is meant to replicate landfill conditions, testing for leaching of toxic materials in such conditions, and is therefore used to discern whether waste is suitable for dumping in those conditions. It is quite likely that blowing that lead battery up in a desolate location is several times more environmentally thoughtful than sending it off to a dump. (Though, recycling trumps both.)

[Edited on 5-17-2008 by ShadowWarrior4444]

vulture - 17-5-2008 at 01:25

Quote:

You are comparing apples with oranges (again). Lead metal is quite inert in the environment, unless it's in a highly acidic environment. However, and I can't believe I have to mention this on a chemistry forum, a lead battery contains sulfuric acid, with dissolved lead and lead sulfate. Not to mention the PbO2 that's quite reactive toward organic matter. That is ALL going to end up in the soil as more or less soluble lead salts in the end. Do you think that pollution is acceptable?

Quote:

The pollution caused by burying a single battery in the ground is negligible especially if it is picked up afterwards.

He's going to BLOW IT UP. You think the lead will stay nicely in place?

Quote:

I was just about to say something about that. What about the lead sulfate, sulfide and carbonate that's exists throughout the Earth's crust? I'm sure there's even a little natural elemental lead.

Lead ores are insoluble and usually immobile in soil. You can't compare it to a lead acid battery. Furthermore, the concentration for lead stated here, is an average. Usually it'll be much lower and much higher in places were ore is found. Have you ever been to places were high concentrations of lead ore are found? I have. Not much grows there.

Zinc - 17-5-2008 at 10:17

Today we tried to remove the lead from a small car battery. We first broke up the outside layer of plastic with a hammer. I saw something that I thought were lead plates. Upon removing one I notices that it is a grid from lead wire and a gray powder filing the empty space between the strings. Then we burned off the remaining plastic, collected the grids with the powder and the powder that fell out. Upon melting some of the powder we saw that it is actually impure lead powder. We collected all the powder and the grids in a metal container in which we will melt it to cast lead ingots. And would be a good idea to add some charcoal powder to the lead while melting it to reduce any oxides in it?

MagicJigPipe - 17-5-2008 at 14:05

I know that a battery contains PbO2. I know PbO2 is used as the cathode but isn't most of this "reacted" to PbSO4 in a discharged battery (which should be virtually insoluble and is a component of some lead ores if I'm not mistaken)? Also, I don't consider any pollution acceptable, just some worse than others.

Zinc, I don't think it would hurt to try and reduce the oxides in the lead. It would certainly make a more pure product. However, I believe lead forms an oxide coating similar to aluminum (this is from memory so I could be wrong) which is (part of) the reason why it is virtually inert to sulfuric acid. For that reason I think even if the lead was pure I would add some carbon just to reduce the oxides that were formed while (s)melting.

That is, if you're going for chemically pure lead and not just lead to be used for bullets, sinkers, structures etc...

12AX7 - 17-5-2008 at 16:09

Charcoal will reduce lead above red heat, so you'll have to superheat it quite a bit. A flux may help (seperate metal from oxide and oxide reduction), for which borax might be suitable. I don't think you want to mess around with a silica based slag which melts up around yellow heat (gague being silica based, this is of course the choice of primary lead smelters). A steel crucible should be fine (lead does not dissolve iron appreciably), but may react with molten or dissolved oxides (slag, etc.).

Tim

Zinc - 18-5-2008 at 02:52

Quote:

Originally posted by vulture
He's going to BLOW IT UP. You think the lead will stay nicely in place?

Yes it will. As I said it will be buried. So the parts will remain in the ground and we will recover them.

JohnWW - 18-5-2008 at 11:23

Some other uses of Pb: It could be rolled into sheets and used as flashing in roofing, or for a corrosion-resistant roof made entirely of Pb sheet; oxidized by heating in air to PbO and this used in glass-making to make heavy "crystal" glass (about 30 to 35% PbO, especially useful for paperweights and heavy glass vessels less easily tipped over) or as a white paint and glaze pigment if TiO2 cannot be obtained; or oxidized further to Pb3O4 ('red lead"), and this used as a pigment in paints and glazes, as a fungicide, and as a seed coating to discourage birds from eating the seeds.

Mr. Wizard - 19-5-2008 at 09:44

I found this link yesterday.
http://www.pyrobin.com/files/thermit(e)%20journal.pdf

It had a section on using lead sulfide ore (Galena) with aluminum to produce pure lead. I don't recommend doing this with lead battery components as it may be a little TOO successful and fast. But the interesting part was if they used a little extra aluminum with the sulfide it remained as ball on top of the lead after the reaction, and was 'hard'. They are actually trying to produce Aluminum Sulfide. Here is the text:

"The presence of sulphide of lead as an impurity is guarded against by keeping a slight excess of aluminium in the charge, which excess of metal will be found after casting the molten product as a hard, brittle, and easily detachable button on the surface of the lead. Aluminium will not alloy with lead, but it will form alloys with iron, silicon, copper, silver, gold, &c. The excess of metallic aluminium therefore performs the double function of keeping the sulphide of aluminium pure, and of removing all iron, copper, &c., from the lead, giving to the latter remarkable purity and softness. Further, by judiciously mixing the aluminium and the galena, this excess button removes any precious metals which may be contained in the sulphide of lead, much in the same manner as zinc desilverizes lead in the Parkes process. (The addition of a small percentage of aluminium to the zinc used in the Parkes process permits of a higher temperature being used ; it prevents the format on of oxide or zinc and effects better separation of the precious metals."

So lead can be purified by mixing it with molten aluminum. This is a little inconvenient as the temperature is above what a normal lead pot will produce, but it is easily available with aluminum casting equipment. I wonder what the vapor pressure of lead is at the melting point of aluminum? I know from personal experience that any zinc in a lead pot will cause problems. The zinc causes the lead to have a 'skin' which interferes with mold filling and pouring.

[Edited on by Mr. Wizard]

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