Sciencemadness Discussion Board

"Reclaimed" battery acid - purification & uses

RogueRose - 5-1-2016 at 19:23

I am curious about what may be contained in battery acid obtained from old lead-acid batteries. What kind of impurities may there be (I'm guessing lead and maybe some antimony??) and is there anything else present in used acid from a Lead-acid battery. I guess we would have to assume that there may be some contaminates from the occasional person trying to revitalize the battery with whatever the current battery saver is.

Is it possible to purify the acid through some filtration and or possible distillation?

I'm also wondering what may be some uses of the acid if it is not possible to clean it to a level usable for say battery acid or possibly drain cleaner (assuming there is no lead, had it ever been present).
As far as volume, I'm talking about about 55gals of liquid/acid from old batteries.

JJay - 5-1-2016 at 19:49

You could concentrate and distill the sulfuric acid to purify it. That's not my idea of a good time--it would be dangerous, smelly, toxic, and there would be lots of nasty fumes, but that's a large quantity of sulfuric acid.... There are almost undoubtedly heavy metal contaminants, and there could be some organic matter as well.

RogueRose - 5-1-2016 at 22:42

Quote: Originally posted by JJay  
You could concentrate and distill the sulfuric acid to purify it. That's not my idea of a good time--it would be dangerous, smelly, toxic, and there would be lots of nasty fumes, but that's a large quantity of sulfuric acid.... There are almost undoubtedly heavy metal contaminants, and there could be some organic matter as well.


I'm trying to figure out whether a weekly influx of 55 gals of old bat acid is going to be a net liability or if it can be processed/reclaimed to a useable/sellable product.

Obviously with the scale I'm talking about, it will become a small industrial production or I'm wondering if there are companies that will buy chems like this and they handle the purification of the product.

JJay - 5-1-2016 at 22:56

You could produce pretty high-grade acid through distillation; whether that is cost effective for you on that scale, I can't say. An environmental company that deals with such things on a regular basis can probably do it more efficiently, but I don't know offhand if they pay money for or charge money for taking battery acid.... I am guessing that you can probably work out a favorable arrangement.

j_sum1 - 5-1-2016 at 23:13

I would begin by working with a small amount and analysing it. Find out how much lead is dissolved. Find out how much Pb remains after distillation. Investigate other possibilities for processing it -- you might for example react with scrap copper and crystallise some copper sulfate. Or you might get hold of some nitrates and produce nitric acid. 55 gallons per week of H2SO4 is a lot. If you decide to go for it you will need a dedicated equipment set up and you will need to have thought through waste disposal thoroughly.

Remember that, at least in the US, OTC sulfuric acid does contain a lot of impurities (or so I am lead to believe.) It is still a useful product for many applications. Your main goal would be to get rid of anything toxic or hazardous. No scratch that. Your main goal is to work out if there is a market for what you can reasonably produce from the acid.

RogueRose - 6-1-2016 at 03:44

Quote: Originally posted by j_sum1  
I would begin by working with a small amount and analysing it. Find out how much lead is dissolved. Find out how much Pb remains after distillation. Investigate other possibilities for processing it -- you might for example react with scrap copper and crystallise some copper sulfate. Or you might get hold of some nitrates and produce nitric acid. 55 gallons per week of H2SO4 is a lot. If you decide to go for it you will need a dedicated equipment set up and you will need to have thought through waste disposal thoroughly.

Remember that, at least in the US, OTC sulfuric acid does contain a lot of impurities (or so I am lead to believe.) It is still a useful product for many applications. Your main goal would be to get rid of anything toxic or hazardous. No scratch that. Your main goal is to work out if there is a market for what you can reasonably produce from the acid.


Thanks for the thoughtful replies! I agree with you on all the points. I'm wondering if there are any uses for not-so clean H2SO4. One quick Q - If the acid were distilled, does the water come over first or will the acid/water mix come over all at once. I'm wondering if it is possible to skip the step of boiling it down to concentrate it. That would be nice!

I guess if I find a good application that doesn't need concentrated SA then the concentration step can be either greatly reduced or maybe even eliminated.

Thanks again!