Sciencemadness Discussion Board

Bulk acid from batteries (deep cycle, marine & car) - possible contaminates?

RogueRose - 30-9-2016 at 22:46

I was told a local company drains their batteries before shipping them for recycling (or maybe rebuilding??) to save on freight and hazmat fees. Battery acid at NAPA is like 31% or so (IDK if that is by weight or volume). I was kind of interested in a drum (price was right!!) but I am worried that maybe the previous owners of the batteries watched some YT videos where they tell you "get 5 more years from your battery by adding : MgSO4, (NH4)2SO4, AlSO4, or even FeSO4 (all fertilizer grade).


So. of Mr yokle had 10 2v forklift batteries that had like 5 gallons of acid each and he decided to treat them with one of the above, what can be expected of the quality and contamination of the battery acid.

What I fear worst is someone adding Alum (don't know exact type, they always just say "alum" to make a "dry cell" deep cycle that "never dies" and "brings battery back from dead".


So, I'm wondering if I were to acquire a 25 gallon drum of this (no charge) how can I verify whether it has a lot of adulterants in it that are unwanted.?

I did find something interesting recently about CuSO4. I had tried dehydrating in convection oven after 3 filtering's and re-crystallization. I used a glass "dish" (casarole like dish - 13x9x 3" deep) and covered with Al foil to block direct heat from elements. I would get "burnt spots" on top of the dish with green, dark green, tan brown and even BLACK! IT formed a crust and underneath was the beautiful blue pentahydrate crystals. The discolored crystals seemed to return to normal (color) when water was added. So getting anhydrous is tough. I did try heating 3lbs pentahydrate in about 2L of 70% H2SO4 and it seemed to turn to a SUPER-FINE white powder. If this is the anhydrous (which seems to be as it turned blue with water), how can it be cleaned so there is no acid left in the powder?

wg48 - 1-10-2016 at 04:55

I would think it would be difficult to determine all possible contaminants but why bother. If nothing else it will have a few mg of lead sulphate per liter so just distilling it will remove that and any other salts and if you really want to know the contaminants you can analyse the crude left after distillation.

You will need to filter it first in my experience there is lots of solid contaminates in the acid.

j_sum1 - 1-10-2016 at 05:13

Distillation is probably the way to go. But read up on it first because the temp is high, thermal stress will be an issue and the whole process is not straightforward.

OTOH, free sulfuric acid is nothing to be sniffed at.

Sulaiman - 1-10-2016 at 06:25

The only danger that comes to me is Arsenic,
the lead is 'strengthened' with antimony,
and antimony often contains arsenic, I think.
selenium and/or calcium may be present also as lead 'strengtheners'
barium and other stuff is in the electrode paste.
https://en.wikipedia.org/wiki/Lead%E2%80%93acid_battery


P.S. even antimony can be nasty if nascent hydrogen is available to form stibine.

[Edited on 1-10-2016 by Sulaiman]

diddi - 1-10-2016 at 22:58

I tried that path and it was useless in a chemistry setting. good for cleaning . that's about it