Production Of Aluminum Powder.
Aluminum Powder is a key reagent in many pyrotechnic reactions. It is can be used in the production of ferroaluminum thermite, flash powder, and fireworks. While aluminum powder can be purchased online, it can be difficult obtain locally. Below are some steps that can be taken to produce aluminum powder:
Etch-A-Sketches contain a very small amount of very fine aluminum powder. Breaking one of these open is an ideal way to obtain a small but high quality amount of aluminum powder. If you are looking for a large amount this method will require a lot of Etch-A-Sketches.
- Remove the plastic covering, depending on the model you have you may have to pry it off or it may be held on by screws. This should reveal a glass faceplate.
- Use caution when forcing the glass plate off, as the aluminum powder will stick to everything it touches. Under the glass plate you will see the inner working of an Etch-A-Sketch plastic beads, and aluminum powder.
- Use a small amount of water to wash the aluminum powder and plastic beads into a container. This will allow the beads to float and easily be removed.
- Decant the excess water and sent the container in the sun to dry.
If you have old aluminum tubing or bars laying around you can use a file and manually file down the aluminum into powder. This method can be cheap and yield good quality aluminum powder, however be prepared to work.
- Aluminum rods and tubing can be found at the local hardware
store or even in your backyard if you hang on to odds and ends
- Most files will work, as aluminum is a softer metal. If you
cannot locate one, they can be purchased from the local hardware store.
- It is recommend that you do your filing over
a plaster container to catch all the powder. A 13’ by 6’ plastic container
should do the trick.
The last method is the cheapest and the best if you want to produce large amounts of aluminum powder. The resulting powder will be rather low quality though. You will need aluminum foil, an old blender, rock tumbler, and steel balls (sling shot ammo works great).
- Tear the aluminum foil in to tiny strips about 1cm by
2cm. This will be slightly time consuming but the aluminum foil does not need
to be perfectly torn. A penknife can be used to quickly cut strips.
- Put some of the strips in the blender and turn it on puree.
Slowly feed in the remaining strips of aluminum foil until there the aluminum is
granular. This will destroy your blender blades and you probably won’t want to
be making any smoothies in blender after.
- After foil has been puréed shake it into the rock tumbler. The
size of the tumbler will limit the amount you can produce at one time. Consult
the user’s manual for information about capacity. Once the powder is loaded,
add the steel balls. Again the size of the tumbler will dictate how many balls
you can add, but you should have at least 25 for an average sized tumbler.
- Turn on tumbler and let set for about 2 weeks, depending how
fine you wish powder to be.
- Open the tumbler every day or every other day to allow the aluminum to oxidize.
- The mesh, fineness, of the grain can be increased by using a mortar
and pestle to grind the powder down more.
In all of these methods it should be noted the powder produced is not pure aluminum. It is Aluminum(III) Oxide Al2O3 also known as Alumina. Due to its nature, pure aluminum reacts with oxygen to immediately form a coating of aluminum oxide by the following reaction:
4Al3+(s) +3O2 (g) → 2Al2O3 (s)
This coating protects the aluminum inside from further oxidation and renders the aluminum oxide skin relatively inert at low temperatures. If alumina is heated to high temperatures, about 1000 degrees Celsius, it becomes reactive with other compounds and will expose the aluminum it is protecting.
You can store your aluminum powder in a variety of containers as your aluminum powder will not be reactive with glass or plastics. I use mason jars as they can be sealed to keep out water and new air. This allows you the benefit of stopping any oxidation that maybe continuing, this is small benefit though because almost all of the powder will have oxidized. When storing, be aware that the flash point of pure aluminum powder is 760 degrees Celsius.
Please be aware that there is a certain risk you absorb when following the procedures. You are responsible if your blender breaks, tumbler over heats, or you incur some form of body harm. Also if you intend to use aluminum powder for any explosives, please be aware that I am not responsible for your actions and any bodily harm you incur. You should check into your local laws that govern the possession and use of explosives.