Aluminum Scrap & Recycling

In the first step of the aluminum recycling process, a professional works with two different types of aluminum scrap — new and old scrap. New scrap is extra aluminum material produced as an offshoot of the manufacturing and fabrication processes. For instance, extrusions or offcuts of aluminum sheets are considered new scrap. Because its composition is known, new scrap can be recycled safely by aluminum smelters.

Old scrap is aluminum that has been used by consumers and discarded. Examples of old aluminum scrap include car cylinder heads, electrical cabling, window frames and used beverage cans. The composition of old scrap may be contaminated and is typically unknown, meaning smelters cannot safely accept the material. 

In addition to these two types of aluminum scrap collected during the first stages of the aluminum recycling process, smelters can collect aluminum from other community areas. These include local and regional authorities, scrap merchants, households and other sources. 

Aluminum scrap is sorted in the second step of the aluminum recycling process. Aluminum smelters group all uncoated aluminum and all coated — lacquered or painted — aluminum together. 

Non-aluminum materials are removed in this stage. This done by feeding the aluminum through a sorter — which separates out other distinctive materials like glass and plastic — and a magnet, which removes other metals like steel.

In the third step, sorted aluminum scrap is compacted by being crushed into bales. This process ensures reduced handling, storage and freight costs. 

Any coated aluminum scrap is processed in a gas-fired rotary furnace. This process removes any coating on the aluminum scrap before it’s transferred to the remelter or large furnace. Uncoated aluminum scrap is directly loaded into a remelter, where it converts into molten form after being heated at high temperatures. 

Melting aluminum typically generates a byproduct known as white dross, which contains about 15% to 80% aluminum mixed with impurities. Recyclers generally skim off the white dross to recover its aluminum content. 

In the last step of the aluminum recycling process, molten aluminum is cast at high temperatures to form ingots or pieces of the aluminum cast into suitable shapes for processing. Ingots are then transferred to aluminum manufacturing or processing plants to be made into new products. 

Recycling aluminum saves 90% of the energy required to mine and process primary aluminum. This number is so large partly because extracting bauxite and using it to produce new aluminum is incredibly energy intensive, using approximately twice the amount of energy required to create new plastic. Using recycled aluminum reduces energy consumption and all the environmental harms that go along with it. 

Reducing energy consumption also means decreasing fossil fuel use. Recycling aluminum instead of creating more primary aluminum reduces the harms associated with fossil fuel burning and leaves more of this finite resource available for future use.

Minimizing fossil fuel consumption contributes fewer pollutants to the atmosphere and lowers levels of the greenhouse gas emissions that cause climate change. One wrinkle here is that recycling itself requires fossil fuel consumption and produces carbon emissions, so recycled aluminum water cans, for instance, are not entirely environmentally blameless. However, compared with new plastic water bottles and the carbon costs for producing them, aluminum cans still reduce emissions substantially.