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Archive for April, 2010

Car Battery Salvage

As a follow up to my Lantern Battery Salvage, I thought I’d do an article on car batteries and the useful things that can be found in them. Car batteries are a little hard to come by; I got mine from a lawn mower that was being scrapped, but you could also check your local dump for one. Keep your eyes open though, because they can be almost as useful in pieces as they are whole. From a good battery you can get lead, lead dioxide, and sulfuric acid. Each of these is useful in some way.

1. The first thing I did was charge the battery to its full capacity, as a dead battery contains no sulfuric acid, lead, or lead dioxide, only lead sulfate. Old batteries should be avoided too, for the reason that as they get older less and less of the lead sulfate converts back into its components.

2.Once it was charged I drilled a hole into the base of each cell and drained the sulfuric acid into a glass jar. I dripped a little onto the wooden deck I was working on which didn’t worry me until I noticed that the screws were fizzing. After washing it off with baking soda water there was a white mark where the acid had bleached it back to it’s original color. I decided it might be a good idea to continue on the gravel driveway.

3.  Next, I used a Dremel Tool to cut off the top and reveal the plates. If the battery is charged then the positive terminal is connected to lead dioxide and the negative terminal to lead. In my battery the lead dioxide was a powder pressed onto a grid and the lead was in a plastic bag. If the battery is uncharged then all of the plates will be lead sulfate.

4. It took about an hour to pull the plates out and separate the chemicals from the battery. I didn’t use gloves for this because my leather gloves tore open, and the acid stung like hell and stained my fingers for a couple days.

5. To purify the sulfuric acid I let the lead settle and filtered it. I will probably boil it later to concentrate it.

So to sum up, I got two jars of sulfuric acid, lead, and lead dioxide, all of dubious purity. I had planned of making a lead dioxide anode but electroplating is more trouble than it’s worth and the other method I’d heard of – mixing lead dioxide with epoxy- gives too much resistance to be viable.

Just as a demonstration of the sulfuric acid, these are the gloves and pants that I was wearing during all of this.

Categories: Chemicals, Chemistry