It’s easy to melt aluminum cans and foil to recycle the pure metal. Aluminum is useful because it’s lightweight, safe for use around food and skin, malleable, and corrosion-resistance. Pour the molten aluminum into molds to make cookware, jewelry, sculptures, or ornaments.
Melting Point of Aluminum
Recycling cans and foil is simple, but it’s an adult-only project because you need a high temperature. The melting point of aluminum is 660.32 °C or 1220.58 °F. This is much higher than the heat produced by an oven or grill (which is why aluminum is great for cookware), but lower than the melting point of iron (1535°C or 2795 °F) or stainless steel (around 1500 °C or 2750 °F). To reach the melting point of aluminum, you need a butane torch (1430 °C or 2610 °F), a propane torch (1995 °C or 3623 °F), or a kiln.
Materials for Melting Aluminum
Basically, all you need are some aluminum cans, an iron or steel container, and a heat source. Be sure you wear protective clothing because molten metal is hot!
- Aluminum cans or foil
- Butane or propane torch or electric kiln
- Cast iron skillet or steel bowl
- Heat-resistant gloves
- Metal tongs
- Molds for the melted aluminum
It isn’t necessary to clean the cans before melting them, unless they are covered in dirt or sand. Organic material, like leftover soda or plastic coatings, will burn off during the melting process.
How to Melt Aluminum
- Crush the cans and crumple foil to get as much as possible into your bowl or skillet. Expect to get about one pound of aluminum for every 40 cans.
- Safety first! Put on safety glasses and heat-resistant gloves. Tie back long hair and wear long pants and shoes with covered toes.
- If you’re using a kiln, heat it to 1220 °F or slightly higher (being careful to stay under the melting point of steel or iron, whichever you are using). Place the container of aluminum in the kiln. It will melt almost immediately once it reaches its melting point, but allow at least 30 seconds for all of the aluminum to melt. While wearing heat-protective gloves, use tongs to carefully remove the container from the kiln.
- If you’re using a torch, place the container of aluminum on a heat-safe surface. Heat the aluminum, taking care to avoid blasting the container. This is especially important if you’re using a propane torch because propane can burn at a temperature hot enough to melt iron and steel!
- Once you have molten aluminum, pour it into your mold (search YouTube for creative ideas). You can place the mold full of aluminum into a bucket of cold water, but use caution because the heat will produce a lot of steam. Otherwise, allow the mold to cool and solidify on its own. It will take about 15 minutes for the metal to harden.
- You may have some leftover aluminum in your container. You can knock it out of the container by tapping it against a hard surface. Another option is to free it by changing the temperature of the container (either by heating or cooling it). This works because aluminum and the container have a different coefficient of expansion values.
Recycling Aluminum
Around 36% of aluminum in the U.S. comes from recycled metal, while Brazil leads the world in aluminum recycling by re-using 98.2% of the metal. Recycling requires 5% of the energy needed to purify the element from its ore.
References
- Greenwood, Norman N.; Earnshaw, Alan (1997). Chemistry of the Elements (2nd ed.). Butterworth-Heinemann. ISBN 978-0-08-037941-8.
- Morris, J. (2005). “Comparative LCAs for curbside recycling versus either landfilling or incineration with energy recovery”. The International Journal of Life Cycle Assessment, 10(4), 273–284.
- Oskamp, S. (1995). “Resource conservation and recycling: Behavior and policy”. Journal of Social Issues. 51 (4): 157–177. doi:10.1111/j.1540-4560.1995.tb01353.x
- Schlesinger, Mark (2006). Aluminum Recycling. CRC Press. ISBN 978-0-8493-9662-5.