Aluminum is a common and useful metal, known for its corrosion resistance, malleability, and for being lightweight. It's safe enough to be used around food and in contact with skin. It's much easier to recycle this metal than it is to purify it from ores. You can melt old aluminum cans to get molten aluminum. Pour the metal into a suitable mold to make jewelry, cookware, ornaments, sculptures, or for another metalworking project. It's a great introduction to home recycling.
Key Takeaways: Melt Aluminum Cans
- Aluminum is an abundant and versatile metal that is easily recycled.
- The melting point of aluminum is low enough that it can be melted with a hand-held torch. However, the project goes more quickly using a furnace or kiln.
- Recycled aluminum can be used to make sculptures, containers, and jewelry.
Materials for Melting Aluminum Cans
Melting cans is not complicated, but it's an adult-only project because high temperatures are involved. You'll want to work in a clean, well-ventilated area. It's not necessary to clean the cans before melting them since organic matter (plastic coating, leftover soda, etc.) will burn off during the process.
- Aluminum cans
- Small furnace of the electric kiln (or another heat source that reaches the appropriate temperature, such as a propane torch)
- Steel crucible (or other metal with a melting point much higher than aluminum, yet lower than your furnace-could be a sturdy stainless steel bowl or a cast iron skillet)
- Heat-resistant gloves
- Metal tongs
- Molds into which you'll pour the aluminum (steel, iron, etc.-be creative)
Melting the Aluminum
- The first step you'll want to take is to crush the cans so that you can load as many as possible into the crucible. You'll get about 1 pound of aluminum for every 40 cans. Load your cans into the container you're using as a crucible and place the crucible inside the kiln. Close the lid.
- Fire up the kiln or furnace to 1220°F. This is the melting point of aluminum (660.32 °C, 1220.58 °F), but below the melting point of steel. The aluminum will melt almost immediately once it reaches this temperature. Allow half a minute or so at this temperature to assure the aluminum is molten.
- Put on safety glasses and heat-resistant gloves. You should be wearing a long-sleeve shirt, long pants, and covered toe shoes when working with extremely hot (or cold) materials.
- Open the kiln. Use tongs to slowly and carefully remove the crucible. Do not place your hand inside the kiln! It's a good idea to line the path from the kiln to the mold with a metal pan or foil, to aid in clean-up of spills.
- Pour the liquid aluminum into the mold. It will take about 15 minutes for the aluminum to solidify on its own. If desired, you can place the mold in a bucket of cold water after a few minutes. If you do this, use caution, since steam will be produced.
- There may be some leftover material in your crucible. You can knock the dregs out of the crucible by slapping it upside down onto a hard surface, such as concrete. You can use the same process to knock the aluminum out of the molds. If you have trouble, change the temperature of the mold. The aluminum and mold (which is a different meta) will have a different coefficient of expansion, which you can use to your advantage when freeing one metal from another.
- Remember to turn off your kiln or furnace when you're done. Recycling doesn't make much sense if you're wasting energy, right?
Did You Know?
Re-melting aluminum to recycle it is far less expensive and uses less energy than producing new aluminum from the electrolysis of aluminum oxide (Al2O3). Recycling uses about 5% of the energy needed to make the metal from its raw ore. About 36% of aluminum in the United States comes from recycled metal. Brazil leads the world in aluminum recycling. The country recycles 98.2% of its aluminum cans.
- 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. p. 248. ISBN 978-0-8493-9662-5.