The Battery Project

Ben recently posted about the “science project” he and I did to dispose of a bunch of old batteries. He provided some great photos, but didn’t go into much detail about what we actually did. I’d like to describe the procedure we used.
First of all, let me explain how this project happened in the first place. Disposing of used batteries is a bit complicated for most people. First you have to do some research to find out where and when you can turn them in for recycling (at your local waste management authority’s household hazardous waste collection, or a business near you that accepts used batteries for the Rechargeable Battery Recycling Corporation). Then you have to pack up all your dead batteries and make a special trip to drop them off. But if you work at IBM, getting rid of your used batteries is much simpler, because IBM sites have special receptacles for batteries in employee break areas, right next to the recycling bins for aluminum cans and plastic bottles. So you just have to take your batteries to work with you.
Last summer, while visiting Marie’s family in Charleston, I noticed that they had a gallon pickle jar in their garage that was completely full of batteries. Marie’s brother Harold explained that he had been collecting them for some time (because he knew that they shouldn’t be put into the trash), but he wasn’t sure how to actually dispose of them. I told him about the receptacles where I work and said I would take care of them, and we brought the jar home with us.
But those IBM receptacles have a label warning that leaking batteries are not accepted. It was obvious that some of the batteries in Harold’s jar had leaked, and the stuff that leaked out of them had gotten all over the rest of the batteries. Most, if not all, of the batteries in the jar were probably fine for recycling, but they would have to be cleaned first. And that task was daunting enough that I put it off for several months, while the jar sat on our kitchen table.
Finally, I decided it was time to deal with the problem. But cleaning these batteries would involve more than just washing them off. I would have to chemically neutralize the leaked material. And not all of that was the same, because the batteries were of different types.
So the first step was to sort them out. This involved putting on a pair of latex gloves, unscrewing the lid of the jar, pulling out batteries one at a time, and sorting them into two plastic dishpans: one for alkaline batteries and the other for acid batteries. When I finished, there was a small amount of liquid in the bottom of the jar. Since the vast majority of the batteries had been alkaline, I concluded that the liquid was alkaline as well. I diluted it with a cup or two of water and then poured in some vinegar (a mild acid). This caused the liquid to begin fizzing — a chemical reaction was taking place, producing bubbles of gas — which meant that I had been right. It was alkaline. I kept adding vinegar and mixing until the fizzing stopped, indicating that the alkaline stuff had been neutralized. I diluted it with a lot more water and then poured it down the drain.
Now to deal with the batteries themselves. I took the dishpan containing the alkaline batteries, added enough water to cover them, and then added some vinegar. More fizzing. Ben continued adding vinegar while I stirred up the batteries with my gloved hands, until the fizzing stopped. I poured off the neutralized liquid, refilled the dishpan with warm soapy water, and washed the remaining crud off the batteries. Pulling out a few at a time, I rinsed them clean and handed them to Ben for drying; he put them into a cardboard box.
When all the alkaline batteries were clean and dry, we repeated the process with the acid batteries, using baking soda (a mild alkaline) instead of vinegar. Then I washed out the pickle jar with soap and water. The result was a clean jar and a cardboard box full of clean batteries. I inspected the batteries and found that none of them seemed to be leaking now. A few (like the 9-volt one that Ben took several photos of) had enough surface corrosion that I thought the IBM collection program probably wouldn’t want them. I set these aside for disposal at the Wake County collection site. The pickle jar went into our recycling bin with the rest of our glass jars, plastic bottles, and empty cans.
I could theoretically have taken the whole box of batteries to work at once, but it was really heavy. So I decided to spread them out over several days. I filled four quart-size Ziploc storage bags with batteries and took one of them to work with me each day until they were all gone. After three days of this, the receptacle in our first-floor break room was too full to take any more, but fortunately our building has another break room on the third floor. The receptacle there was almost empty, so I dumped the last bag of batteries in. The labels on these receptacles include a phone number to call when one is full; I called and reported that the first-floor one needed to be emptied.
Thus ends the saga of the Giant Jar of Batteries.

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