Sciencemadness Discussion Board

Reducing lead

tumadre - 2-6-2005 at 22:27

I have 40-60 pounds of pbo, pbso4 and pbo2.
What is the easiest way to reduce all this at the same time? This material is from several car batteries that I removed the h2so4 from after obtaining them from a junkyard.

12AX7 - 3-6-2005 at 01:22

And you can't use them for anything? :o I'd mix with magnesium and blow something up. :P

If you don't mind the fumes, smelting is simple enough - mix charcoal with oxides and sulfates (sulfides will need to be roasted, but it doesn't sound like that's a problem), heat to around yellow heat (mind the fumes, lead oxides are volatile at this temperature) and periodically drain off the metallic lead.

This is usually done in a cupola style blast furnace, you can look up some designs on foundry sites. If you don't want to go the direct route, you can always mix crushed materials in a crucible and heat to redness (or higher, if needed).

I think soda (and/or lime at higher temps) can optionally be used as flux, but with clean "ore", that shouldn't be an issue?

Tim

Mr. Wizard - 3-6-2005 at 08:30

I know of a guy who built a rotary kiln smelter to burn old batteries and recover the Lead. He ran it and made such a stink it caused the authorities to respond. They warned him the first time, and the second time more serious action was taken. He ran it in an industrial area, after normal working hours. The amount of SO2 and SO3 involved with a battery burning is a terrible thing to be around, not to mention the Lead and Antimony fumes. I know it's obvious, but if you want more Sulfuric Acid in the electrolyte and less Sulfate in the plates, charge the battery up before you pull it apart.

unionised - 4-6-2005 at 07:55

Repeated boiling of PbSO4 with Na2CO3 soln will convert it to PbCO3. That way you don't have SO2 fumes to deal with.

Pyridinium - 4-6-2005 at 12:32

Quote:
Originally posted by Mr. Wizard
They warned him the first time, and the second time more serious action was taken.


One warning and you'd think he'd have stopped. Burning storage batteries??? That is nuts. Although you have to admire anyone who builds their own rotary kiln.

Did he take any steps to collect or process the SO2 and SO3, or did it all just go into the air? That would have been a tragic waste!

TheBear - 4-6-2005 at 13:41

A bit off topic:

I managed to spill some lead solder on my gas stove which I use in the lab. The amount of solder isn't big, perhaps 0.5 g, should I consider replacing the stove due to the poisonous fumes? Or am I being too concerned? Exactly how nasty are these fumes, I know lead is an accumulative poison but most of the time when I use the stove the fume hood is running and wenting all fumes outside.

[Edited on 4-6-2005 by TheBear]

runlabrun - 4-6-2005 at 16:09

if its lead on a steel stove top you could just get a hand-held gas torch burner and melt it then collect it up, the lead will melt way before the steel.

-rlr

12AX7 - 4-6-2005 at 16:27

Bah, don't mind lead. Just peel and scrape it off, wipe down with a damp rag if necessary and let that be that. The vapor pressure of lead is vanishingly small near the melting point.

Tim

Mr. Wizard - 4-6-2005 at 20:26

"One warning and you'd think he'd have stopped. Burning storage batteries??? That is nuts. Although you have to admire anyone who builds their own rotary kiln.

Did he take any steps to collect or process the SO2 and SO3, or did it all just go into the air? That would have been a tragic waste!"

The guy built a 'battery burner' , for the lack of a better description. It was a rotating metal tube about 75-80 cm inside diameter and about 9 meters long at about a 11 degree angle on rollers. He would put in whole batteries at the top while it was rotating and they would tumble down against metal paddles as he burned propane into the bottom of the tube. I think the plan was to use the case material to fuel it once it got hot enough, and collect the molten scrap lead at the bottom. I can verify it made a stink that covered a few square kilometers. He thought he only got caught by accident, but the next time they smelled the stink, very late at night, the authorities knew right where to go. I think he had so much time and money in it, he didn't want to quit, and he was hard headed as well. He didn't care about the SO2 just the Lead. Once you have 'sensitized' your neighbors to a certain type of activity, they suspect you forever.;)