Intro: Extracting Manganese Dioxide From Batteries
Manganese dioxide is extremely useful to chemists and pyro hobbyists alike, being used to make potassium permanganate as well as some types of thermite. It is a black, water-insoluble solid and is commonly used in schools to demonstrate the actions of catalysts, as it also catalyzes the breakdown of hydrogen peroxide.
We will be extracting it from carbon-zinc electrode batteries, which contain a fair bit of the stuff on the inside, along with several other useful components.
Step 1: Materials/tools:
1. Several D batteries
Make sure these are fresh, or you'll end up with impurities marring the finished product. An AA battery could also work, but D batteries give a lot more manganese dioxide per battery.
2. A pair of needle nose pliers
I didn't have one for this project, so I just went with regular wire clippers instead.
Manganese dioxide will stain your hands, so wear a decent pair of gloves. These also protect you from the sharp metal edges you'll be handling.
4. A disposable working surface (such as newspaper, plastic)
As previously mentioned, manganese dioxide can be hard to remove, so put some newspaper or a plastic sheet on your work area.
5. A medium-sized container of some sort, enough to hold double the volume of the D batteries.
6. Filter paper
You will need to rinse the manganese dioxide after extracting it.
7. A screwdriver or some sort of stick
8. Precision cutter
Step 2: Step 1: Unwrapping the Battery
Look for a chink in the casing of the battery's outside. Taking the pliers, work from the top of the battery and remove the casing through this chink. In most batteries, the casing is crimped such that one layer is under the other, but there are variations across brands. Find what works for you, as using brute force can be frustrating and time-consuming. Remove the entire casing and discard it.
Step 3: Step 2: Removing the Sheath
There should be a plastic sheath underneath the casing. It's tempting to just go straight in and tear it out, but this is harder than it looks. Make an incision with a precision cutter down the length of the sheath. This will make it easier to remove. Once the sheath is off, the negative terminal of the battery (the end that goes inwards) should fall out. Discard both of these. The positive terminal should stay on.
Step 4: Step 3: Removing the Positive End
You should be looking at a metal case with the positive terminal on top, separated by a ring of rubber. Grasp the positive terminal firmly with the pliers and twist left and right to remove it, exposing the carbon core. This is basically a carbon electrode. Remove it using the same method as you did with the positive terminal. The rubber ring should also come off. You should now have exposed a layer of cardboard.
Step 5: Step 4: Managanese Dioxide!
Remove the cardboard with the pliers. If your gloves are still off, put them on now. Things are about to get messy. Using the screwdriver, pry out the black paste underneath. This is the impure manganese dioxide. There will also be a layer of cardboard surrounding the manganese dioxide paste. Try not to take any of it with the manganese dioxide chunks, as this will lead to contamination by the paper. Once the paste is mostly removed, take out tue remaining cardboard pieces and discard them. The casing is zinc metal, and you may want to retain it for any projects in the future. The carbon electrode is also useful.
Step 6: Step 5: Hold On, We're Not Done Yet!
Now, there's quite a bit of stuff mixed in with what you just extracted. Most of it should be harmless to your purposes, and the main issue is the water. It would seem easy to just bake it off, but there's potassium hydroxide in it as well. You'll need to rinse that off first. Add sufficient mineral water to the paste to produce a thin, runny black liquid. Run this through a coffee filter.
Step 7: Step 6: Baking
After the liquid is done filtering, you should have a black paste. Bake this in the oven for about half an hour to completely purge any water from the paste. There you have it. Manganese dioxide.