Chemistry is my new hobby (very new) so forgive me if I make mistakes in terminology, or worse.
Step 1: Materials
1. Steel wool. (I use Grade #0000 Other grades will work but I use the finest for faster results)
You can get this at any paint store, including the paint department at Wal-Mart.
2. A flat, non-reactive, non-porous, clean surface to work on. (I use the glass tray from an old microwave.)
3. 2 spray bottles. (1 if you don't use salt)
One of these should be non-transparent because it will hold hydrogen peroxide and any light will quickly cause decomposition of the peroxide. You can buy small dark bottles of peroxide at most drug stores, including Wal-Mart.
4. Table Salt. (optional)
A cup or so will last a while for most people.
5. 3% (or higher) Hydrogen Peroxide.
6. A plastic spoon (or something like it)
7. A magnet that will fit in your spoon (or whatever) without protruding over the edge.
Step 2: Preparing the steel wool
I use regular non-scented dish soap and water and just wash and rinse it several times. You can also use Acetone, if you have any, for the final rinse.
Let the steel wool dry well before moving on. I use my kitchen oven to dry it. If you decide to use your oven, BE CAREFUL, especially if you used Acetone to rinse. As counter-intuitive as it may be, steel wool ignites pretty easily and burns pretty hot. In fact, a 9V battery will ignite it almost instantly.
Step 3: The Setup
Spray the wool with the peroxide that you have in the dark bottle. (You DID use a dark bottle didn't you?) Just enough to thoroughly soak it. Any puddling around the wool is wasted peroxide and will only serve to prolong the time it takes the wool and surface to dry.
I'm not exactly sure if it contaminates the product or not, but I use a sodium catalyst to speed the process up. I have been using this method from the beginning and it hasn't caused any problems with the Iron Oxide as my experiments with it go. If you chose to do this, simply mix some table salt and warm water in the other spray bottle and shake it well. Spray just enough to cover the steel wool completely. Less is more. Remember this isn't necessary to begin with so don't dilute the peroxide.
You can see some rust forming the the image. This was sprayed just minutes before the picture was taken. The oxide should come to the surface of the steel wool pretty quickly depending on how well you cleaned the wool and if you chose to use a catalyst.
Let this set overnight, or until it has dried completely and rust can be shaken out of the remaining iron.
Step 4: Harvesting
After the wool is dry and you are confident that oxidization has slowed to a crawl (I leave it overnight between steps) you can begin to extract some product and repeat the last step.
With a solid, flat, non-porous object (I use a flat-bottomed glass), crush the wool, as if you are trying to make a powder of it, until the bulk of the rust is release from the remaining steel wool.
Remove what part of the steel wool that you can manually and shake all the rust that you can from it before setting it to the side.
Now that the bulk of the remaining wool is removed, crush the pile of (mostly) rust again to make a powder as fine as you can get it.
Unless you are really good at manually removing the steel wool, you will still have a lot of iron in the pile. The best way that I have found to separate the remaining iron from the desired product is to use a magnet in a spoon (I'm working on an electromagnet with a variable power supply that will be much better, but for now this works). With the magnet in the plastic spoon, hover over the pile just enough to attract the iron particles but not enough to attract the oxide. The distance will depend on the magnet and the spoon that you use but with practice it become easy and surprisingly effective. When you have lifted all the iron that the magnet is capable of attracting, simple remove the magnet from the spoon, dropping the iron in a separate pile, and start over. Do this until the only thing left in the pile in Iron(II) Oxide, then scrape this up and put it in an appropriate container.
Place all your iron wool and small particles back on your oxidization surface (microwave tray in my case) and go back to step 3, spraying and waiting again.
Repeat this until you have converted all of the steel wool to Iron(II) Oxide. It has taken me between 2 and 4 days. This seems like a lot until you consider that it would take the same amount of time to do a much larger batch. Theoretically, with enough steel wool and peroxide, any volume of iron oxide could be produced in this amount of time.
Thank you for reading my first instructable. I hope it is of some help. I would like to give credit to my son Christian, who has been an invaluable member of my "lab team" and has helped a great deal in developing this method. :)